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In tribological applications, the degradation of alloy nitride coatings is an issue of increasing concern. The drawbacks of monolayer hard coatings can be overcome using a multilayer coating system. In this study, single-layer TiAlNbN and multilayer TiAlNbN/AlCrN coatings with AlCrN layer addition into TiAlNbN were prepared by cathodic arc evaporation (CAE). The multilayer TiAlNbN/AlCrN showed B1 NaCl structure, and the columnar structure continued from the bottom interlayer of CrN to the top multilayers without interruption. After AlCrN addition, the TiAlNbN/AlCrN coating consisted of TiAlNbN and AlCrN multilayers with a periodic thickness of 13.2 nm. The layer thicknesses of the TiAlNbN and AlCrN were 7 nm and 6.2 nm, respectively. The template growth of the TiAlNbN and AlCrN sublayers stabilized the cubic phases. The introduction of bottom CrN and the TiAlNbN/CrN transition layers possessed com-position-gradient that improved the adhesion strength of the coatings. The hardness of the deposited TiAlNbN was 30.2 ± 1.3 GPa. The TiAlNbN/AlCrN had higher hardness of 31.7 ± 3.5 GPa and improved tribological performance (wear rate = 8.2 ± 0.6 × 10−7 mm3/Nm) than those of TiAlNbN, which were because the multilayer architecture with AlCrN addition effectively resisted abrasion wear. [ABSTRACT FROM AUTHOR]

Titanium (Ti) and Ti alloys possess extensive applications in the medical field due to their non-toxic, biocompatible, and antibacterial properties. This study investigates the biocompatibility enhancement of a Ti-based alloy, Ti-6Al-4V, through a multi-step process involving cathodic arc ion plating of a TiZrTa thin film and subsequent laser-textured oxidation (LTO). LTO treatment produced a structured microtopography with regular groove patterns, including straight lines (L-s), circles (L-c), and checkboards (L-ch), resulting in surface oxidation and the formation of various oxides on the TiZrTa coating. Microstructure analyses revealed substantial alterations in surface topography induced by laser texturing. Antibacterial assessments against Staphylococcus aureus (S. aureus) showed that the films with LTO treatment did not exhibit significant advantages after 12 or 24 h of coculture because the laser-textured portions consisted of a combination of the film and the substrate, and the antibacterial effect was not obvious. Coatings with LTO treatment significantly improved L-929 mouse fibroblasts cell viability at 48 h, particularly for samples with a 50 μm spacing of straight and circular patterns (L-s and L-c). After two weeks of MG-63 human osteosarcoma cell culture, the viability of all samples reached similar levels. It suggested that the TiZrTa-coated Ti-6Al-4V exhibited good biocompatibility with both cells. This study contributed to the understanding of surface modification techniques for enhancing the biocompatibility of Ti-based alloys in biomedical applications. • A TiZrTa thin film with LTO treatment was applied onto Ti-6Al-4V alloys. • LTO produced regular groove patterns and resulted in superior hydrophilicity. • LTO-treated thin films did not have obvious antibacterial improvement of S. aureus. • LTO-treated thin films improved the cell viability of both L-929 and MG-63 cells. [ABSTRACT FROM AUTHOR]

Developing a TiAlN-based hard coating with a multilayer structure comprising multiple nitride components shows potential to enhance the overall performance of high temperature applications. In this study, multi-target cathodic arc evaporation was utilized to deposit multilayer coatings comprising of nanostructured AlCrN/TiAlNbN and AlCrBN/TiAlNbSiN. The focus of this study is to analyze how the different coatings undergo structural changes due to the growth of oxide scale and diffusion processes that take place during oxidation when subjected to high temperatures of 900 °C, and the roles of B and Si addition in their oxidation resistance were examined. The deposited AlCrN/TiAlNbN coating showed a typical columnar structure with nanolayer stacking (average bilayer periodic thickness ~ 14.8 nm). The surface formed an oxide layer rich in titanium oxide, while the internal oxide layer of the AlCrN/TiAlNbN coating that underwent oxidation contained mixed metal oxides with a dominant composition of Al 2 O 3 , which hindered additional oxidation. The AlCrBN/TiAlNbSiN coatings, which had average bilayer periodic thickness 11.4 nm ~12.2 nm, showed fine-fibrous growth morphologies and refining effects of B and Si in the AlCrBN/TiAlNbSiN coatings, and they possessed better high temperature oxidation resistance thang that of AlCrN/TiAlNbN. Due to the formation of a protective oxidized layer with a combination of metal oxides, which minimizes the inward diffusion of oxygen during oxidation, the AlCrBN/TiAlNbSiN coating with a thicker AlCrBN layer exhibited the highest resistance to oxidation compared to the other coatings studied. [Display omitted] • AlCrBN/TiAlNbSiN multilayer coatings were deposited using cathodic arc evaporation. • Different oxidation behaviors of the multilayer coatings are studied. • The AlCrBN/TiAlNbSiN coatings showed fine-fibrous growth and refining effects. • A bilayered oxide scale was formed on the AlCrN/TiAlNbN after oxidation. • The multilayer structure of the AlCrBN/TiAlNbSiN is effective in preventing oxidation. [ABSTRACT FROM AUTHOR]

Ternary transition metal nitrides, such as AlTiN, TiSiN and TiBN, have been attracting great interest as hard protective coatings due to their high hardness, wear resistance, and thermal stability. In this study, AlTiSiN and AlTiBN coatings were synthesized by cathodic-arc evaporation using ternary AlTiSi and AlTiB alloy targets. During the coating process of AlTiSiN and AlTiBN, TiN was deposited as an interlayer to enhance adhesion strength between the coatings and substrates. After deposition, the AlTiBN coating was conducted by an oxidation post-treatment at high temperature of up to 800 °C in vacuum and in a controlled atmosphere of Ar and air to synthesize a top oxide layer and improve the tribological performance. The microstructure of the synthesized coatings was studied by a field emission scanning electron microscope (FE-SEM) and a field emission gun high resolution transmission electron microscope (FEG-HRTEM). Ball-on-disc wear tests were conducted to evaluate the tribological properties of the coatings. The AlTiSiN and AlTiBN coatings possessed higher hardnesses and lower wear rates than AlTiN. After oxidation post-treatment, the AlTiBN coating contained an oxide layer composed of nanocrystalline Al 2 O 3 and TiO 2. The result of ball-on-disc wear tests showed that the lowest wear rate was obtained for the AlTiBN coating after oxidation post-treatment, which was significantly better than that of the AlTiN, AlTiSiN and AlTiBN. • AlTiN, AlTiSiN and AlTiBN coatings were deposited by CAD. • After deposition, the AlTiBN coating was conducted by an oxidation post-treatment. • AlTiSiN and AlTiBN coatings had higher hardnesses and lower wear rates than AlTiN. • The lowest wear rate was obtained for the AlTiBN after oxidation post-treatment. [ABSTRACT FROM AUTHOR]

By adding V atoms to TiN, the tribological and mechanical properties of TiVN coatings are improved. Multilayered coatings, rather than monolayered ones, may further enhance the mechanical properties and thermal stabilities of TiVN. Therefore, an approach was employed in this study to synthesize gradient-and-multilayered CrMoN/TiVN coatings through vacuum arc ion plating. During the impact fatigue test that utilized a cyclic loading device, the correlation between cyclic impact resistance and coating structures of the deposited coatings were evaluated. Vacuum annealing and high temperature oxidation at temperatures exceeding 600 °C were used to assess the thermal stability of the coatings. Although the as-deposited TiVN coating achieved the highest hardness of 30.2 ± 2.5 GPa, the CrMoN/TiVN multilayer coating only experienced a slight decrease to 29.1 ± 2.2 GPa, which exceeded the solid solution quaternary CrMoTiVN mixture rule prediction. When compared to the high-hardness monolayered TiVN and the low-hardness CrMoN, the CrMoN/TiVN multilayer coatings demonstrated the best resistance to cyclic impact. The TiVN coating displayed the worst oxidation resistance, as shown by the emergence of elongated vanadium-rich Ti-V oxide slats on the surface after oxidation. The CrMoN coating exhibited higher oxidation resistance than TiVN, and small granular chromium oxides formed on the surface beyond 700 °C. The addition of CrMoN to TiVN to form CrMoN/TiVN resulted in improved oxidation resistance by inhibiting the oxidation of TiVN. A different oxidation behavior was found for the CrMoN/TiVN coatings. The design of gradient-and-multilayered CrMoN/TiVN coatings is proven to be advantageous for applications that aim to enhance the thermal stability and cyclic impact resistance of mechanical tools. • Gradient-and-multilayered CrMoN/TiVN coatings through vacuum arc ion plating • The CrMoN/TiVN multilayer coatings had the best resistance to reciprocating impacts. • The growth of CrMoN/TiVN nano-multilayers exhibited coherent multilayer interfaces. • The addition of CrMoN in multilayers resulted in improved oxidation resistance. • Different oxidation behaviors were found for the CrMoN/TiVN coatings. [ABSTRACT FROM AUTHOR]

The flexibility of the physical vapor deposition (PVD) method in obtaining coatings with a delicate control at a nanometric level provides superior properties. Among these coatings, transition metal nitride coatings based on Ti, Si, Al and V, such as TiAlN, TiSiN and TiVN, have been attracting great interest for industrial applications as protective coating materials due to their high hardness, wear resistance and tribological performance. In this study, TiVN, TiSiN and multilayered TiVN/TiSiN coatings were deposited onto tungsten carbide tools using cathodic-arc evaporation (CAE) system. During the coating process of TiVN/TiSiN, TiN was deposited as an interlayer to enhance adhesion strength between the coatings and substrates. The main objective of the present work is to investigate the effect of TiVN on the microstructure, mechanical properties and tribological performance of the deposited TiVN/TiSiN coatings by regulating the bias voltage during the coating process. The multilayered TiVN/TiSiN coatings exhibited higher hardness of 35–37 GPa, indicating higher resistance against plastic deformation compared to TiVN and TiSiN. The result of ball-on-disc wear tests and end milling tests of 7000 series Al alloys showed that the lowest wear rate and the longest tool life were obtained for the multilayered TiVN/TiSiN coating deposited at high bias voltage of 180 V, which was significantly better than that of the monolayered TiSiN. [ABSTRACT FROM AUTHOR]

Development of oxide films on metallic implants with a desirable combination of mechanical properties and biocompatibility can greatly improve its functionality and application to the medical implant field. The present work is aimed to fabricate titanium (Ti) or zirconium (Zr) oxide films with porous structures onto Ti substrates by micro-arc oxidation (MAO) procedure. Before the MAO treatment, a series of Ti Zr alloy films were deposited on polished pure Ti substrates using a cathodic arc deposition system with different deposition cathode current ratios of Zr/Ti. The post-MAO-treated surface layers were characterized for its composition, crystalline structure, bonding states, surface morphology, and wettability. The results showed that porous crystalline titanium and zirconium oxides were formed using the MAO treatment for the Ti Zr films. To evaluate the bioactivity, cell viability and gene expression of human osteosarcoma cell line (MG-63) and human skin fibroblast cell line (SKF) cultured on different Ti Zr oxide films were determined. The results of MTT tests showed that the higher cell viability of MG-63 and SKF cells was found in MAO-treated Ti Zr films with higher Zr content. Gene expression data by RT-PCR and agarose gel electrophoresis showed that MG-63 cells and SKF cells exhibited notable osteogenic gene expression, such as Runx2, ALP, Dlx-5, OCN, BMP-2 and BMPR1A. The cell adhesion-related genes, such as fibronectin, collagen types I and III, and laminin were also remarkably expressed in the gel imaging. It suggested that the MAO-treated Ti Zr films were suitable for bone tissue- or soft tissue-derived cell growth and differentiation. The design and fabrication of Ti Zr oxide films with specific composition and porous surface layer with MAO treatment may provide a better material environment for cell bonding, living, and differentiation in dental and orthopedic implants. [ABSTRACT FROM AUTHOR]

Wear resistant hard coatings are highly demanded in modern manufacturing industry to ensure good performance of cutting and forming tools. In this study, TiVN, CrAlSiN and multilayered CrAlSiN/TiVN coatings were synthesized by cathodic-arc evaporation (CAE). TiV and CrAlSi alloy cathodes were used for the deposition of multilayered CrAlSiN/TiVN coatings. The cathode current and bias voltage of both TiV and CrAlSi cathodes were controlled at 70 A and − 120 V, respectively. By controlling the rotation speed of 4 rpm, a stepwise columnar structure containing periodic CrAlSiN and TiVN layers was found in this multilayered CrAlSiN/TiVN coating. The modulation period of the deposited CrAlSiN/TiVN coatings was 9 nm. The CrAlSiN/TiVN coatings possessed higher hardness of 33 GPa as compared to TiVN and CrAlSiN (24 GPa26 GPa). After oxidation at 500 °C, the TiVN revealed the presence of TiO 2 , V 2 O 5 and VO 2 on the surface. Small fraction of oxygen displaced nitrogen. Titanium and vanadium oxides were formed. The XPS, XRD and SEM analyses only suggested small amounts of titanium and vanadium oxides on the surface of the multilayered CrAlSiN/TiVN after oxidation at 500 °C. To study the impact fracture resistance, an impact test using a cyclic loading was conducted. The multilayered CrAlSiN/TiVN coating exhibited the best impact resistance (higher than 4 × 10 5 impacts) at room temperature and 500 °C, indicating the best resistance to impact fracture, among the studied coatings. The multilayered structure with TiVN and CrAlSiN is responsible for the enhanced mechanical properties, oxidation resistance and impact resistance. [ABSTRACT FROM AUTHOR]

A cathodic-arc evaporation system with plasma-enhanced duct equipment was used to deposit TiZrN, TiZrCN, and TiZr/a-C coatings. Reactive gases (N 2 and C 2 H 2 ) activated by the Ti and Zr plasma in the evaporation process was used to deposit the TiZrCN and TiZr/a-C coatings with different C and nitrogen contents. The crystalline structures and bonding states of coatings were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. The microbial activity of the coatings was evaluated against Staphylococcus aureus (Gram-positive bacteria) and Actinobacillus actinomycetemcomitans (Gram-negative bacteria) by in vitro antibacterial analysis using a fluorescence staining method employing SYTO9 and a bacterial-viability test on an agar plate. The cell compatibility and morphology related to CCD-966SK cell-line human skin fibroblast cells on the coated samples were also determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, reverse-transcriptase-polymerase chain reaction, and scanning electron microscopy. The results suggest that the TiZrCN coatings not only possess better antibacterial performance than TiZrN and TiZr/a-C coatings but also maintain good compatibility with human skin fibroblast cells. [ABSTRACT FROM AUTHOR]

Multicomponent and multilayer coatings have been attracting significant research interest, and these coatings allow the deposition of graded layers with a continuous variation of the concentration of the components to fulfill specific requirements at the substrate interface or that at the surface. On the basis of the binary compounds TiN, CrN and ZrN, various deposition strategies were developed to improve or adapt the hard coatings to a specific tribological problem. In this study, a cathodic arc deposition technology was used to deposit the AlTiSi/CrV/Zr and multilayer nitride coatings of AlTiSiN/CrVN/ZrN. By controlling the rotation speed of the substrate, hierarchical gradient and multilayered structures containing periodic AlTiSiN, CrVN and ZrN layers were found in the multilayer nitride coatings. Microstructure, mechanical properties and cutting applications were discussed. The highest hardness was obtained for the multilayered AlTiSiN/CrVN/ZrN coating with modulation period of 13.5 nm. The presence of multicomponent AlTiSiN/CrVN/ZrN with nanolayer structure mainly attributed to the formation of strong metal‑nitrogen bonding enhanced the hardness of the coatings. For the field test of cutting, a glass-reinforced epoxy laminate material was machined by the coated WC-Co end mills using a milling machine at high cutting spindle rotational speed of 40,000 rpm. The obtained results showed that the periodic thickness of the multilayer structure had a direct effect on the mechanical properties and cutting performance of the coatings. The design of nanostructured AlTiSiN/CrVN/ZrN hard coatings improved the overall tribological performance and showed applicability of these coatings in high speed cutting of glass-reinforced epoxy laminate materials. • Multilayered AlTiSiN/CrVN/ZrN coatings were deposited using cathodic-arc deposition. • The AlTiSiN/CrVN/ZrN coating with modulation period of 13.5 nm had the highest hardness. • Good adhesion strength was obtained with composition-gradient interlayers and multilayer structures. • The design of nanostructured AlTiSiN/CrVN/ZrN improved the cutting performance. [ABSTRACT FROM AUTHOR]

The surface characteristics of biomaterials play an important role in their interaction with biological systems. Tantalum (Ta) oxides and their coatings have been proved to increase their applications in the biomedical fields such as medical devices and dental implants by improving their osseointegration and corrosion resistance. In this study, Ta and amorphous tantalum oxide coatings were deposited by using magnetron sputtering. A hydrophilic crystalline β-Ta 2 O 5 coating was obtained by rapid thermal annealing of the deposited tantalum oxide coating at 700 °C. In this study, Staphylococcus aureus and Actinobacillus actinomycetemcomitans ( A. actinomycetemcomitans ) are Gram-positive and Gram-negative bacteria, respectively, that exhibit physiological commensalism on the human skin and oral areas. Both bacteria were chosen as the model for in vitro anti-bacterial analyses by a fluorescence staining method employing Syto9. The cytocompatibility of human skin fibroblast cells (CCD-966SK) on the coatings was also determined using an MTT assay. It showed that the amorphous tantalum oxide coatings possessed good antibacterial performance, while the hydrophilic crystalline tantalum oxide coatings exhibited outperformed human skin fibroblast cellular biocompatibility. [ABSTRACT FROM AUTHOR]

Recently, multicomponent CrAlSiN and TiAlSiN coatings have been developed in order to gain high hardness and good thermal stability. In this study, the influence of TiAlN, CrAlSiN and TiAlSiN coatings on the wear behavior and cutting performance of the carbide cutting tools was investigated in dry machining of a Ti–6Al–4V alloy. TiAlN, CrAlSiN and TiAlSiN coatings were deposited on tungsten carbide milling inserts by using cathodic arc evaporation. The deposited TiAlN, CrAlSiN and TiAlSiN possess high hardness of 31 ± 1 GPa, 36 ± 2 and 35 ± 2 GPa, respectively. After annealing at 700 °C in air, the hardness of the CrAlSiN and TiAlSiN still keeps as high as 35–36 GPa, while the hardness of TiAlN decreases to 26 GPa. The main wear modes for the TiAlSiN-, TiAlN coated- and uncoated tools are abrasion and adhesion. The nanocrystalline TiAlSiN coatings retard the tool wear as compared to the TiAlN-coated tools. At a high cutting speed of 350 m/min, the tool life of the CrAlSiN coatings exceeds the TiAlSiN-, and TiAlN-coated and uncoated tools by 2.9, 4.2 and 9.5 times, respectively. The CrAlSiN coatings show high wear resistances in dry machining of Ti–6Al–4V alloys, and thus possess the best cutting performance. [ABSTRACT FROM AUTHOR]

Abstract: Tantalum is considered a highly biocompatible metal with high corrosion resistance. Metal-doped amorphous carbon films are gaining interest as an effective surface modifier for medical devices. In this study, tantalum (Ta), TaC/amorphous carbon (a-C), and Ta-containing amorphous hydrogenated carbon films (Ta-C:H) were synthesized using a twin-gun magnetron sputtering system to improve biological properties and explore potential applications for surgical implants or devices. Reactive C2H2, activated by the tantalum plasma in the magnetron sputtering process, was used to deposit the Ta-C:H coatings. The deposited TaC/a-C coatings, in which TaC was embedded in the amorphous carbon matrix as a nanocomposite film, exhibited favorable cell viability of the human osteosarcoma cell line (MG-63), similar to uncoated titanium. Among the examined materials, Ta-C:H coatings exhibited the highest biocompatibility for WS1 human fetal skin fibroblast cells derived from soft tissues and demonstrated the highest biological performance. [Copyright &y& Elsevier]

Tantalum (Ta) is a promising metal for biomedical implants or implant coating for orthopedic and dental applications because of its excellent corrosion resistance, fracture toughness, and biocompatibility. This study synthesizes biocompatible tantalum carbide (TaC) and TaC/amorphous carbon (a-C) coatings with different carbon contents by using a twin-gun magnetron sputtering system to improve their biological properties and explore potential surgical implant or device applications. The carbon content in the deposited coatings was regulated by controlling the magnetron power ratio of the pure graphite and Ta cathodes. The deposited TaC and TaC/a-C coatings exhibited better cell viability of human osteosarcoma cell line MG-63 than the uncoated Ti and Ta-coated samples. Inverted optical and confocal imaging was used to demonstrate the cell adhesion, distribution, and proliferation of each sample at different time points during the whole culture period. The results show that the TaC/a-C coating, which contained two metastable phases (TaC and a-C), was more biocompatible with MG-63 cells compared to the pure Ta coating. This suggests that the TaC/a-C coatings exhibit a better biocompatible performance for MG-63 cells, and they may improve implant osseointegration in clinics. [ABSTRACT FROM AUTHOR]

Abstract: This study used a twin-gun magnetron sputtering system to deposit ZrO2-silver (Ag) coatings on biograde pure-titanium implant materials, and the Ag content in the deposited coatings was controlled by the magnetron power. The films were then annealed using rapid thermal annealing at 350°C for 2min to induce the nucleation and growth of nanoparticles on the film surface. Staphylococcus aureus (S. aureus) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) were used for in vitro antibacterial analyses. The cytocompatibility, mRNA expression, and adhesive morphology of human gingival fibroblast (HGF) cells on the coatings were also determined. The obtained results suggest that ZrO2-Ag composite coatings containing less than 10.6at.% Ag show hydrophobicity, good viability and proliferation of HGF cells, and antibacterial effects on S. aureus and A. actinomycetemcomitans. Moreover, the antibacterial performance of ZrO2-Ag coatings is superior to that pure-titanium whilst maintaining biological compatibility. [Copyright &y& Elsevier]

The phenomenon of glass-to-mold sticking is a major problem for industrial glass forming processes. Recently, multicomponent CrAlSiN films attracted considerable industrial interest because of their excellent tribological performance and high oxidation resistance at high temperatures exceeding 800°C. Metal plasma ion implantation has being successfully developed for further improving wear, corrosion and physical properties of engineering materials. In this study, Mo and carbon ions were implanted into the multicomponent CrAlSiN film by using a metal-plasma ion implantation apparatus. The accelerating voltage of metal ions was set at 40kV with implantation doses of 1×1017 ions/cm2 for Mo and 2×1017 ions/cm2 for carbon. After Mo and carbon ion implantation, molybdenum carbides were found in the implanted layer of CrAlSiN. The wettability of the ion implanted CrAlSiN films by molten glass at 500°C in controlled air under 1.7Pa was measured by using a sessile drop method. Mo and carbon ion implanted CrAlSiN films showed the lowest wettability of all tested samples, which is attributed to a reduced adhesion of molten glass at high temperature. The ion implanted CrAlSiN films showed an anti-sticking characteristic superior to the as-deposited CrAlSiN films. Results of this study demonstrate the potential of metal plasma ion implantation in improving the anti-sticking behavior of the CrAlSiN films by molten glass. [ABSTRACT FROM AUTHOR]

In this study, multilayered AlTiN/ZrN and AlTiN/CrN/ZrN coatings with CrN layer addition were prepared by cathodic arc evaporation (CAE) system using AlTi target, Cr target and Zr targets. According to the XRD and TEM experimental results, the coatings are all B1 NaCl structure, and the columnar structure continues from the bottom CrN to the top multilayered coating and the growth of the columns is not interrupted. After CrN addition, the AlTiN/CrN/ZrN coating consisted of ZrN, AlTiN and CrN multilayers. By increasing the cathode current of Cr, thicker CrN layers were obtained. The nanoindentation results showed that the AlTiZrN had the highest hardness of 30.4 GPa and residual stress of −3.1 GPa, mainly due to the contribution of ZrN into AlTiN. The multilayered Al 12 Ti 7 Cr 12 Zr 22 N and Al 8 Ti 5 Cr 21 Zr 17 N coatings with different CrN layer thicknesses had lower hardness values. Compared to the low hardness of CrN (~18 GPa), the multilayered AlTiN/CrN/ZrN coating still possessed high hardness enough. In addition, after CrN addition, the multilayered Al 12 Ti 7 Cr 12 Zr 22 N and Al 8 Ti 5 Cr 21 Zr 17 N coatings had lower residual stresses (−1.6–2.6 GPa). The low residual stress of the hard coating is beneficial for tribological applications. For the ball-on-disc tribological tests, although the AlTiN/ZrN coating had the highest hardness but it had the highest wear rate (4.96 × 10−6 mm3/Nm). The multilayered Al 12 Ti 7 Cr 12 Zr 22 N coatings with thin CrN layer addition and small Cr content had the best wear performance with the lowest wear rate of 4.21 × 10−7 mm3/Nm. The results showed that the special multilayered AlTiN/CrN/ZrN hard coating possessed better wear performance than that of AlTiN/ZrN coating, which was due to the fact that the multilayer architecture with CrN addition effectively released the internal stress to resist abrasion wear. • Multilayered AlTiN/CrN/ZrN coatings with CrN layer addition were deposited. • The multilayered AlTiN/ZrN had the highest hardness and residual stress. • The multilayered AlTiN/CrN/ZrN coating had the lowest residual stress by CrN addition. • The multilayered AlTiN/CrN/ZrN with thin CrN layer possessed the lowest wear rate. [ABSTRACT FROM AUTHOR]

Abstract: Composite metal nitride–metal (MeN–Me) physical vapor deposited (PVD) films (e.g. TaN–Cu, TiN–Cu, ZrN–Ag, etc.) are often considered for applications such as tribological and antibacterial coatings. In this study, ZrN, ZrO2–Ag and ZrNO–Ag coatings with different Ag contents were deposited by reactive magnetron sputtering. Monoclinic ZrO2 and fcc Ag composite structures were obtained when Zr and Ag were cosputtered to react with oxygen. ZrNO–Ag showed a porous structure containing monoclinic ZrO2, fcc Ag and Zr2ON2. Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) and Staphylococcus aureus (S. aureus), major pathogens frequently found in the implant-associated infections, were cultured on the coated samples. The antibacterial effects were determined using in vitro anti-bacterial analyses by a fluorescence staining method employing Syto9 and bacterial viability agar tests. In addition, the biocompatibility of human gingival fibroblast (HGF) cells on coatings was also evaluated by a MTT test assay. It showed that the nanostructure and Ag content of the ZrO2–Ag and ZrNO–Ag coatings were correlated with the biocidal property. The ZrN coating deposited by magnetron sputtering did not improve the bacterial reduction of A. actinomycetemcomitans and S. aureus. The ZrO2–Ag and ZrNO–Ag coated samples had lower bacterial retention, and the ZrNO–Ag coatings with silver content of 11.8at.% possessed the best antibacterial performance with excellent HGF cell compatibility as well. [Copyright &y& Elsevier]

The phenomenon of glass-to-mold sticking is a major problem for industrial glass forming processes. Ternary TiAlN coatings attracted considerable industrial interest because of their excellent tribological performance and high oxidation resistance at high temperatures. Recently, multicomponent CrAlSiN and TiAlSiN coatings have been developed in order to gain high hardness and good thermal stability at temperatures exceeding 800°C. In this study, CrAlSiN, TiAlSiN and AlTiN coatings were deposited on tungsten carbide substrates by using a cathodic-arc deposition system with lateral rotating arc cathodes. Titanium, chromium and AlSi (12at.% of Si) cathodes were used for the deposition of CrAlSiN and TiAlSiN coatings. All the deposited CrAlSiN, TiAlSiN and AlTiN coatings showed a B1-NaCl crystal structure. The deposited CrAlSiN and TiAlSiN coatings exhibited nanocrystalline structure and possessed hardness as high as 35–37GPa after annealing at 700°C in air. The wettability of the CrAlSiN, TiAlSiN and AlTiN coated tungsten carbides by molten glass at temperatures between 300°C and 700°C in controlled air under 1.6Pa was measured by using an improved sessile drop method. The CrAlSiN showed a low oxidation rate and a non-wetting characteristic superior to TiAlSiN and AlTiN coatings. [ABSTRACT FROM AUTHOR]

Abstract: Transition metal nitrides, such as ZrN and TiAlN, have been used as protective hard coatings due to their excellent tribological properties. In this study, ZrN, TiAlN and multilayered TiAlN/ZrN coatings were synthesized by cathodic-arc evaporation with plasma enhanced duct equipment. Zirconium and TiAl (50at.% of Al) alloy cathodes were used for the deposition of TiAlN/ZrN coatings. During the coating process of multilayered TiAlN/ZrN, ZrN was deposited as an interlayer. With different cathode current ratios (I[TiAl]/I[Zr]) of 0.75, 1.0, and 1.33, the deposited multilayered TiAlN/ZrN coatings possessed different chemical contents and modulation periods. The nanolayer thickness and alloy content of the deposited coating were correlated with the evaporation rate of cathode materials. Modulation period and layer thickness ratio of TiAlN/ZrN increased with increasing I[TiAl]/I[Zr] cathode current ratio. The multilayered TiAlN/ZrN coatings possessed higher hardness of 33–38GPa than that of the monolayered ZrN(30GPa) and TiAlN(31GPa) coatings. To study the correlation between impact fracture resistance and hardness/modulus ratio, an impact test was conducted using a tungsten carbide ball as an impact indenter. The multilayered TiAlN/ZrN coating with the lowest modulation period (25nm) and the highest layer thickness ratio of TiAlN/ZrN (0.92) exhibited the best impact resistance (higher than 1×105 impacts) and the highest H3/E⁎2 ratio value of 0.443GPa, indicating the best resistance to plastic deformation, among the studied TiAlN, ZrN and multilayered TiAlN/ZrN coatings. [Copyright &y& Elsevier]

Objective: The purpose of this study was to verify the antibacterial performance and cell proliferation activity of zirconium (Zr)–carbon (C)–nitride (N) coatings on commercially pure titanium (Ti) with different C contents. Materials and Methods: Reactive nitrogen gas (N2) with and without acetylene (C2H2) was activated by Zr plasma in a cathodic-arc evaporation system to deposit either a zirconium nitride (ZrN) or a Zr–C–N coating onto Ti plates. The bacterial activity of the coatings was evaluated against Staphylococcus aureus with the aid of SYTO9 nucleic acid staining and scanning electron microscopy (SEM). Cell compatibility, mRNA expression, and morphology related to human gingival fibroblasts (HGFs) on the coated samples were also determined by using the MTT assay, reverse transcriptase–polymerase chain reaction, and SEM. Results: The Zr–C–N coating with the highest C content (21.7 at%) exhibited the lowest bacterial preservation (P<0.001). Biological responses including proliferation, gene expression, and attachment of HGF cells to ZrN and Zr–C–N coatings were comparable to those of the uncoated Ti plate. Conclusions: High-C-content Zr–C–N coatings not only provide short-term antibacterial activity against S. aureus but are also biocompatible with HGF cells. [ABSTRACT FROM AUTHOR]

Abstract: Bacterial adhesion and colonization are considered to play key roles in the pathogenesis of peri-implant disease, which is an inflammatory process leading the destruction of both soft and hard tissue around a Titanium (Ti) implant. The osseointegration of Ti implants is influenced by their composition and surface treatment. Zirconia (ZrO2) coatings have been shown to improve implant osseointegration in various biomedical fields, including orthopedic devices and dental implants. This study used a twin-gun magnetron sputtering system to deposit ZrO2–Sliver (Ag) and ZrO2–Copper (Cu) coatings on biograde pure-Ti implant materials. The effects of Ag and Cu on the antibacterial properties of the coated Ti samples were investigated using Staphylococcus aureus (S. aureus) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), which are found frequently in implant-associated infections. The in vitro antibacterial analyses employed a fluorescence staining method using SYTO9 and bacterial-viability tests on agar plates. Incorporating Ag and Cu into ZrO2 changed the structure of crystalline ZrO2, and the nanostructures of the resulting ZrO2–Ag and ZrO2–Cu coatings were found to be correlated with the antibacterial performance. The adherence of S. aureus and A. actinomycetemcomitans was less for ZrO2 samples with a small doping of Cu than for uncoated Ti. The ZrO2–Ag coating with an Ag content of 10.6at.%, which showed hydrophobicity, exhibited the lowest bacterial retention and viability of S. aureus and A. actinomycetemcomitans. The results suggest that ZrO2–Ag and ZrO2–Cu coatings improve the antibacterial performance relative to pure-Ti implant materials. [Copyright &y& Elsevier]

Abstract: Titanium (Ti)-based materials have been used for dental and orthopedic implants because of their excellent biological compatibility, superior mechanical strength, and high corrosion resistance. The hypothesis of this present study was to manufacture the Zn-doped TiO2 layer possessing the biocompatibility and antibacterial ability on the surface of Ti specimens. TiO2, ZnO, and Ti(Zn)O2 coatings were deposited on polished pure Ti substrates using a cathodic arc deposition system. Murine osteoblasts (MC3T3-E1) and human Staphylococcus aureus (S. aureus) were cultured onto the surface with different deposited coatings, respectively. The biocompatibility was examined by cell viability and osteogenic gene expression. The antibacterial ability was determined by SYTO9 nucleic acid staining. A porous Zn-doped TiO2 coating was successfully produced. The ZnO exhibited a fibrous structure with nanorods showing a hydrophobic feature (contact angle approximately 89°). These material properties affected the following biological performance. The antibacterial testing found no apparent difference between the uncoated Ti plate and the TiO2 coating. However, significantly lower numbers of S. aureus were observed on ZnO and Ti(Zn)O2 coatings compared to that on the uncoated Ti. The biocompatible testing exhibited that TiO2 and Ti(Zn)O2 coatings enhanced greater cell viability and proliferation than the uncoated Ti plate and ZnO coating. The osteogenic gene expression of Dlx-5 and osterix also improved for the TiO2 and Ti(Zn)O2 coatings. However, a significant inhibition of cell viability was found for the ZnO coating. These findings suggested that the composite Ti(Zn)O2 coating with a lower content of Zn (7.6±1.3at.%) not only improved antibacterial activity, but also maintained the biocompatibility to bone cells. [Copyright &y& Elsevier]

Titanium (Ti)-based materials are widely used in biomedical implant components and are applied successfully in various types of bone-anchored reconstructions. However, in dental implants the Ti materials contact not only bone but also gingival tissues, and are partially exposed to the oral cavity that includes bacteria. This study used titania and silver (TiO/Ag) compound coatings and zinc oxide (ZnO) films to enhance the antibacterial activity of the Ti-based implant. The hydrophobicity of each sample was examined by measuring the contact angle. Streptococcus mutans and human gingival fibroblast (HGF) was cultured on the coated samples, and the antibacterial effects and cell compatibility were determined using a Syto9 fluorescence staining and MTT methods. For the TiO/Ag samples, depositing Ag on the plate at a higher power (which increased the proportion of Ag) increased the contact angle and the hydrophobicity. The bacterial count was lowest for the 50 W TiO/Ag sample, which contained 5.9% Ag. The contact angles of the ZnO samples did not show the same tendency. The antibacterial effect was higher on ZnO-coated samples since bacterial count was threefold lower on ZnO samples as compared to control samples (Ti plate). From the MTT assay test, the mean optical density values for TiO/Ag-coated samples after 72 h of HGF adhesion were similar to the value obtained from the uncoated Ti. However, biocompatibility was lower on ZnO films than in control samples. Conclusively, the antibacterial activity was higher but the cell compatibility was lower on ZnO films than on TiO/Ag coatings. [ABSTRACT FROM AUTHOR]

Abstract: Titanium (Ti)-based materials have been used for dental/orthopedic implants due to their excellent biological compatibility, superior mechanical strength and high corrosion resistance. The osseointegration of Ti implants is related to their composition and surface treatment. Better biocompatibility and anti-bacterial performances of Ti implant are beneficial for the osseointegration and for avoiding the infection after implantation surgery. In this study, nanocomposite ZrCN/amorphous carbon (a-C) coatings with different carbon contents were deposited on a bio-grade pure Ti implant material. A cathodic-arc evaporation system with plasma enhanced duct equipment was used for the deposition of ZrCN/a-C coatings. Reactive gas (N2) and C2H2 activated by the zirconium plasma in the evaporation process were used to deposit the ZrCN/a-C coatings. To verify the susceptibility of implant surface to bacterial adhesion, Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), one of the major pathogen frequently found in the dental implant-associated infections, was chosen for in vitro anti-bacterial analyses. In addition, the biocompatibility of human gingival fibroblast (HGF) cells on coatings was also evaluated by a cell proliferation assay. The results suggested that the ZrCN/a-C coatings with carbon content higher than 12.7at.% can improve antibacterial performance with excellent HGF cell compatibility as well. [Copyright &y& Elsevier]

Abstract: Metal plasma ion implantation has being successfully developed for improving the electronic and optical properties of semiconductor materials. Prior to deposition, a TiO2 colloidal suspension was synthesized by microwave-induced thermal hydrolysis of the titanium tetrachloride aqueous solution. The TiO2 thin film was optimized to obtain a high-purity crystalline anatase phase by calcinations at 550°C. The TiO2 coating was uniform without aggregation, which provided good photo conversion efficiency. Ag ion implantation into the as-calcined TiO2 thin films was conducted with 1×1015 ~1×1016 ions/cm2 at 40keV. The peak position and intensity of the photoluminescence and UV–Vis absorption spectra are quite sensitive to Ag doping. The optical characterization showed a shift in optical absorption wavelength towards infrared ray side, which was correlated with the structure variation of the Ag+ implanted TiO2. Due to the strong capability of forming compounds between the energetic silver ions and TiO2, the photoluminescence emission and UV–Vis absorption efficiencies were improved. [Copyright &y& Elsevier]

Abstract: AlxTi1−xN and CrN have been widely used as a protective coating material in many types of tools and mechanical components because of high wear performance and high temperature resistance. In this study, the high temperature oxidation behavior of Al0.63Ti0.37N and multilayered Al0.63Ti0.37N/CrN coatings was studied. These coatings were synthesized by a cathodic-arc deposition system with plasma enhanced duct equipment. The nanolayer thickness and alloy content of the deposited multilayered coating were correlated with the emission rate of alloy cathode materials. The multilayered Al0.63Ti0.37N/CrN coating revealed a laminate structure with stacking of Al0.63Ti0.37N and CrN layers, and the periodic thickness (Λ) was 16nm. For the high temperature oxidation test, the coated samples were annealed in the temperature range of 700–1000°C in air for 2h. The multilayered Al0.63Ti0.37N/CrN possessed much thinner oxide layer thickness than Al0.63Ti0.37N. Even after oxidation at 1000°C, the multilayered Al0.63Ti0.37N/CrN still retained their crystalline structure. An interface effect served as a barrier, and retarded the diffusion of oxygen into the multilayered Al0.63Ti0.37N/CrN. Thus, the multilayered Al0.63Ti0.37N/CrN showed a high temperature oxidation resistance superior to the Al0.63Ti0.37N. [Copyright &y& Elsevier]

The aim of this study was to evaluate the effects of cortical bone thickness and trabecular bone elastic modulus on the strain in the bone surrounding an immediately loaded implant. We also examined the correlations between bone structure and the following indices of primary implant stability: insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ). The ITV, PTV, and ISQ were measured in 24 artificial jaw bone models representing cortical bone with four thicknesses (0, 1, 2, and 3 mm) and trabecular bone with four elastic moduli (137, 47.5, 23, and 12.4 MPa). Two loading conditions were applied (force of 130 N applied vertically and at 45° laterally), and the strains in the crestal region were measured by rosette strain gauges with a data acquisition system. When the cortical bone thickness and the elastic modulus of trabecular bone decreased, the bone strains increased by 10.3-52.1% and 39-73.1%, respectively, for vertical loading and by 35-62% and 42.4-56.2% for lateral loading. The cortical bone thickness has a stronger correlation ( R=0.95-0.71) with ITV, PTV, and ISQ than the elastic modulus of trabecular bone ( R=0.89-0.59). The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the elastic modulus of trabecular bone; however, these parameters are not totally linearly correlated with ITV, PTV, and ISQ. The placement of an immediately loaded implant in cases with thin cortical bone and/or weak trabecular bone can induce extreme bone strains and may increase the risk of implant failure. Huang H-L, Chang Y-Y, Lin D-J, Li Y-F, Chen K-T, Hsu J-T. Initial stability and bone strain evaluation of the immediately loaded dental implant: an in vitro model study. Clin. Oral Impl. Res. , 2011; 691-698 doi: 10.1111/j.1600-0501.2010.01983.x [ABSTRACT FROM AUTHOR]

Abstract: Hydrogenated amorphous silicon (a-Si:H) films show considerable potential for the fabrication of thin film solar cells. In this study, the a-Si:H thin films have been deposited in a parallel-plate radio frequency (RF) plasma reactor fed with pure SiH4. The plasma diagnostics were performed simultaneously during the a-Si:H solar cell deposition process using an optical emission spectrometer (OES) in order to study their correlations with growth rate and microstructure of the films. During the deposition, the emitting species (SiH*, Si*, H*) was analyzed. The effect of RF power on the emission intensities of excited SiH, Si and H on the film growth rate has been investigated. The OES analysis revealed a chemisorption-based deposition model of the growth mechanism. Finally, the a-Si:H thin film solar cell with an efficiency of 7.6% has been obtained. [ABSTRACT FROM AUTHOR]

Abstract: Nickel incorporated amorphous hydrogenated carbon (Ni/a:C–H) thin films were deposited onto the Si substrates via biased target ion beam sputtering of nickel combined with reactive ion beam deposition of a:C–H using CH4/Ar gas mixture. The effects of Ni doping and target bias voltage on the microstructure and mechanical properties of the as-deposited films were investigated by means of X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, transmission electron microscopy and nanoindentation. It was found that the Ni content in the films gets increased with increasing target bias voltage, and most of the Ni atoms react with C atoms to form NiC x phases in the Ni/a:C–H films. Moreover, the nickel carbide nanoparticles attain crystallinity even at low deposition temperature and get embedded in the cross-linked carbon matrix. It was found that the presence of Ni3C nanoparticles tends to increase the content of sp2 carbon, thus decreasing the hardness of Ni/a:C–H films as compared with that of a:C–H films. Additionally it was found that the nickel incorporated films do not show any adverse effect on the osteoblast cellular adhesion. Overall, these carbidic nanocrystals initiate direct graphitization and intend to change diamond-like to graphite-like carbon structure in Ni/a:C–H films with promising biocompatibility. [ABSTRACT FROM AUTHOR]

Abstract: Titanium-based materials have been used for dental implants due to their excellent biological compatibility, superior mechanical strength and high corrosion resistance. The osseointegration of titanium dental implants is related to their composition and surface treatment. A better anti-bacterial performance of the abutment seated in the prosthetic crown is beneficial for the osseointegration and for avoiding the infection after implantation surgery. In this study, TaN-Ag coatings with different Ag contents were deposited on a bio-grade pure Ti dental implant material. A twin-gun magnetron sputtering system was used for the deposition of TaN-Ag coatings. The Ag content in the deposited coatings was controlled by the magnetron power ratio of Ag/(Ta+Ag) targets. To verify the susceptibility of implant surface to bacterial adhesion, Staphylococcus aureus, one of the major pathogen frequently found in the implant-associated infections, was chosen for in vitro anti-bacterial analyses. In addition, the biocompatibility of human gingival fibroblast (HGF) cells on coatings was also evaluated. A composite structure of crystalline TaN and Ag nanoparticles was identified. The TaN-Ag coating with the highest Ag content of 21.4at.% possessed the lowest bacterial retention and viability of S. aureus. From the MTT assay test, the mean optical density values for the TaN and TaN-Ag coated samples after 72h of HGF adhesion were greater than the value obtained from the uncoated Ti. The results suggested that the TaN-Ag coatings improve antibacterial performance with compatible biological response. [ABSTRACT FROM AUTHOR]

Abstract: Nano-crystalline TiO2 thin films were synthesized by using sol–gel and spin-coating techniques on glass substrates for photo-catalytic applications. Prior to deposition, a TiO2 colloidal suspension was synthesized by microwave-induced thermal hydrolysis of the titanium tetrachloride aqueous solution. In this study, the deposited TiO2 coating with a grain size of 13±2nm was uniform without aggregation. Co ion implantation into the as-calcined TiO2 thin films was conducted with fluences of 1×1015–1×1016 doses/cm2 at 40keV. In addition to the emission of TiO2, the photoluminescence study showed the presence of another Co-related optical center at 405nm in the Co-implanted TiO2 thin films. Due to the strong capability of forming impurity compounds between the energetic cobalt ions and TiO2, the photoluminescence emission and UV–Vis absorption efficiencies were improved. [Copyright &y& Elsevier]

Abstract: Graded and multilayered AlxTi1-xN/CrN coatings were synthesized by cathodic-arc evaporation (CAE) with plasma enhanced duct equipment. Chromium and AlTi alloy cathodes were used for the deposition of AlxTi1-xN/CrN coatings. During the coating process of graded AlxTi1-xN/CrN, an Al0.63Ti0.37N top layer was deposited on an interlayer of Al0.63Ti0.37N/CrN, which was obtained by regulation of cathode power. With different cathode current ratios (Al0.67Ti0.33/Cr) of 0.75, 1.0, and 1.33, the deposited multilayered Al0.63Ti0.37N/CrN coatings possessed different chemical contents and periodic thicknesses. The nanolayer thickness and alloy content of the deposited coating were correlated with the evaporation rate of alloy cathode materials. Periodic thickness and layer thickness ratio of Al0.63Ti0.37N/CrN increased with increasing I [AlTi]/I [Cr] cathode current ratio. High resolution transmission electron microscopy showed that lattice distortion and dislocations are found at the interface between Al0.63Ti0.37N and CrN layers in the multilayered Al0.63Ti0.37N/CrN. Hardness enhancement is a consequence of dislocation blocking. The multilayered Al0.63Ti0.37N/CrN coatings possessed higher hardness (35–36 GPa) and better fracture toughness (K IC =1.65–2.05 MPa m1/2) than those of the graded Al0.63Ti0.37N/CrN. [Copyright &y& Elsevier]

Abstract: Nanosrystalline CrAlSiN and CrTiAlSiN coatings were deposited by using a cathodic-arc deposition system with lateral rotating arc cathodes. Titanium, chromium and Al89Si11 cathodes were used for the deposition of CrAlSiN and CrTiAlSiN coatings. For the high temperature oxidation test, the coated samples were annealed at 900 °C in air for 2 h. The oxidation characteristics of the deposited coatings were also studied by thermal-gravimetric analysis (TGA). In this study, chemical composition and bonding states of the deposited and annealed CrAlSiN and CrTiAlSiN coatings were evaluated by X-ray photoelectron spectroscopy (XPS). All the deposited Cr0.36Al0.57Si0.07N and Cr0.40Ti0.22Al0.36Si0.02N coatings showed B1-NaCl crystal structure and possessed nano-grain sizes of 8–12 nm. The oxide scale formed on the Cr0.40Ti0.22Al0.36Si0.02N coatings consisted of major TiO2 at the surface region, followed by a mixed layer of Al2O3 and Cr2O3 phases. TiO2 grew at an accelerated rate on to the aluminum and chromium oxide layers after oxidation at 900 °C. The oxidation rate of the Cr0.36Al0.57Si0.07N coated sample was much lower than that of Cr0.40Ti0.22Al0.36Si0.02N. A dense protective layer, mainly consisted of Al2O3 and Cr2O3, retarded the diffusion of oxygen into Cr0.36Al0.57Si0.07N. It indicated that Cr0.36Al0.57Si0.07N with higher Al, and Si contents possessed superior oxidation resistance than Cr0.40Ti0.22Al0.36Si0.02N. [Copyright &y& Elsevier]

Abstract: Multicomponent coatings based on different metallic and non-metallic elements possess the combined benefit of individual components leading to further improvement of coating properties. In this study, monolayered Ti–Al–N, multilayered Ti–Al–N/TiN, gradient Ti–Al–Si–N, and multilayered Ti–Al–Si–N/TiN coatings were synthesized by using a cathodic-arc evaporation (CAE) system. In addition to Ti, Ti33Al67 and Al88Si12 cathodes were used for the deposition of Ti–Al–N, and Ti–Al–Si–N coatings, respectively. The gradient Ti0.50Al0.43Si0.07N, and multilayered Ti0.50Al0.43Si0.07N/TiN with nanograins separated by disordered grain boundaries possessed lower residual stress (−2.8~−4.8 GPa) than that of monolayered Ti–Al–N (−6.8 GPa) and multilayered Ti–Al–N/TiN coatings (−5.7 GPa). The highest hardness was obtained for the gradient Ti0.50Al0.43Si0.07N (38±2 GPa) with Ti/(Ti+Al+Si) content ratio being 0.5. On the contrary, the multilayered Ti0.50Al0.43Si0.07N/TiN possessed the highest H 3/E ⁎2 ratio of 0.182±0.003 GPa, indicating the best resistance to plastic deformation, among the studied coatings. [Copyright &y& Elsevier]

Abstract: Recently, nanocomposite coatings have attracted much interest because of their excellent mechanical performance and chemical stability. In this study, Cr–N–C–O nanocomposite coatings were synthesized by cathodic-arc evaporation with plasma enhanced duct equipment. Nitrogen and CO2 reactive gases were introduced to react with chromium to form Cr–N–C–O nanocomosite coatings during the deposition process. The plasma in a cathodic arc evaporation process used for the deposition of Cr–N–C–O coatings was studied by an optical emission spectrometer (OES). With the introduction of nitrogen and CO2 reactive gases into the chamber, high density of evaporated chromium catalyzes the decomposition of nitrogen and CO2 reactive gases, and induces the formation of Cr–N–C–O films. The emission intensity of Cr atoms decreased with increasing N2/(N2 +CO2) flow rate ratio. It showed the deposition rate increased at higher CO2 flow rate. A nanocomposite structure of coexisting CrN, Cr2N and Cr2O3 crystallites and amorphous carbon phases was found in the Cr–N–C–O coatings. [Copyright &y& Elsevier]

Transition metal nitride coatings, such as CrN, AlCrN and AlTiN, have excellent mechanical properties such as high strength, hardness, wear resistance and thermal stability. In this study, AlCrN and AlCrBN thin films were deposited by cathodic arc evaporation (CAE) using binary AlCr and ternary AlCrB alloy targets. The adhesion strength of the films to the substrate was effectively improved using composition-gradient interlayers. To study the thermal stabilities, the AlCrN and AlCrBN coatings were annealed at high temperature up to 900 °C, and their oxidation resistance, mechanical properties and thermal stabilities were studied. AlCrN and AlCrBN coated WC-Co samples were tested using pin-on-disk wear test configuration to evaluate the tribological performance. According to experimental results, the AlCrBN is composed of a face-centered cubic B1 (FCC) nanocrystalline structure, which can effectively inhibit the growth of grains, resulting in formation of a compact structure of grain refinement, and hinder the plastic deformation, thus obtaining high hardness and excellent wear resistance. The addition of 0.6 at.% B into the AlCrN decreased the grain size to 8.7 ± 0.8 nm from 13.7 ± 1.1 nm of AlCrN. Due to the addition of B element, the grains of AlCrBN coatings were refined to form a compact structure. Oxygen (O) did not penetrate and oxidize easily along the grain boundaries during annealing at high temperature. In addition, the AlCrBN coatings maintained a certain hardness (27.9–30 GPa) after high temperature oxidation, and the AlCrBN coating after annealing at 900 °C had the lowest wear rate (1.25 × 10−7 mm3/Nm). The AlCrBN coating annealed at high temperature still possessed predominant tribological properties, excellent thermal stability and good adhesion. This study demonstrates the feasibility of improving the life and performance of WC-Co tools by the application of cathodic arc deposited AlCrBN coatings using ternary AlCrB alloy targets. • AlCrBN coatings were deposited using ternary AlCrB alloy targets. • The addition of small fraction of B into the AlCrN decreased the grain size. • The AlCrBN coating had good thermal stability and oxidation resistance. • The AlCrBN coating showed improved wear resistance especially after annealing at 900 °C. [ABSTRACT FROM AUTHOR]

Background: the clinical application of orthopedic or dental implants improves the quality of the lives of patients. However, the long-term use of implants may lead to implant loosening and related complications. The purpose of this study is to deposit titanium (Ti)-niobium (Nb)-zirconium (Zr)-tantalum (Ta) alloys on the surface of Ti-6Al-4V to increase structural strength and biocompatibility for the possible future application of implants. Materials and methods: Ti, Nb, Zr, and Ta served as the materials for the surface modification of the titanium alloy. TiNbZr and TiNbZrTa coatings were produced using cathodic arc evaporation, and a small amount of nitrogen was added to produce TiNbZrTa(N) film. Annealing and oxidation were then conducted to produce TiNbZrTa-O and TiNbZrTa(N)-O coatings. In this study, biological tests and finite element analyses of those five alloy films, as well as uncoated Ti-6Al-4V, were performed. Human osteosarcoma cells (MG-63) and mouse fibroblast cells (L-929) were used to analyze cytotoxicity, cell viability, and cell morphology, and the bone differentiation of MG-63 was evaluated in an alkaline phosphatase experiment. Furthermore, for measuring the gene expression level of L-929, reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was conducted. The three-dimensional (3D) computational models of the coated and uncoated sample films were constructed using images of transmission electron microscopy and computer-aided design software and, then, the stress distributions of all models were evaluated by finite element analysis. Result: the cytotoxicity test revealed that the surface treatment had no significant cytotoxic effects on MG-63 and L-929 cells. According to the results of the cell viability of L-929, more cell activity was observed in the surface-treated experimental group than in the control group; for MG-63, the cell viability of the coated samples was similar to that of the uncoated samples. In the cell morphology analysis, both MG-63 and L-929 exhibited attached filopodia and lamellipodia, verifying that the cells were well attached. The alkaline phosphatase experiment demonstrated that the surface treatment did not affect the characteristics of early osteogenic differentiation, whereas RT-qPCR analysis showed that surface treatment can promote better performance of L-929 cells in collagen, type I, α1, and fibronectin 1. Finally, the results of the finite element analysis revealed that the coated TiNb interlayer can effectively reduce the stress concentration inside the layered coatings. Conclusions: TiNbZrTa series films deposited using cathodic arc evaporation had excellent biocompatibility with titanium alloys, particularly in regard to soft tissue cells, which exhibited an active performance. The finite element analysis verified that the TiNb interlayer can reduce the stress concentration inside TiNbZrTa series films, increasing their suitability for application in biomedical implants in the future. [ABSTRACT FROM AUTHOR]

Abstract: The high-temperature oxidation behavior of the CrN and Cr–Al–Si–N coatings was studied. These coatings were deposited on silicon substrates by using a cathodic-arc deposition system with lateral rotating arc cathodes. Chromium and Al88Si12 cathodes were used for the deposition of Cr–Al–Si–N coatings. The deposited Cr0.38Al0.56Si0.06N exhibited higher hardness of 41±2GPa and higher H3/E*2 ratio of 0.468GPa than CrN due to the introduction of Al and Si to form a nanocrystalline structure. For the high-temperature oxidation test, the coated samples were annealed at 800°C in air for 2h. The Cr0.38Al0.56Si0.06N possessed much lower oxidation rate as measured by the oxide layer of the coatings. The addition of Al and Si in the coating may inhibit the formation of Cr2N phase and grain coarsening as found in the deposited CrN coating. In addition, the coexisting Al2O3 and SiO2 near the surface retarded the diffusion of oxygen into the Cr0.38Al0.56Si0.06N. The deposited Cr0.38Al0.56Si0.06N showed an oxidation behavior superior to the CrN. The high-temperature oxidation resistance of the CrN coatings can be improved by the formation of nanocomposite Cr–Al–Si–N. [Copyright &y& Elsevier]

Abstract: The plasma in a cathodic arc evaporation process used for the deposition of Cr1−x O x films was studied by an optical emission spectroscopy (OES). With the introduction of Ar and oxygen into the chamber at deposition pressures from 0.7 Pa to 2.7 Pa, high density of evaporated chromium catalyzes the decomposition of oxygen reactive gas, and induces the formation of Cr1−x O x films. Optical emission spectra including atomic and ionized Cr, excited and ionized oxygen revealed that excitation, ionization and charge transfer reactions of the Cr–O plasma occurred during the Cr1−x O x deposition process. A simplified empirical model which incorporates the relevant atomic processes in the gas phase with the chemical composition and deposition rate of the deposited Cr1−x O x coating was developed. Rhombohedral Cr2O3 and tetragonal CrO2 were observed in the Cr1−x O x coatings deposited at higher pressure than 1.3 Pa. The Cr1−x O x coating depicted a dense and compact microstructure with well-attached interface. [Copyright &y& Elsevier]

Abstract: The monolayered TiSiN and multilayered TiSiN/CrN were synthesized by cathodic arc evaporation. The Ti/Si (80/20 at.%) and chromium targets were used as the cathodic materials. With the different I [TiSi]/I [Cr] cathode current ratios of 1.8, 1.0, and 0.55, the multilayered TiSiN/CrN coatings possessed different multilayer periods (Λ) of 8.3 nm, 6.2 nm, and 4.2 nm. From XRD and TEM analyses, both the monolayered TiSiN and multilayered TiSiN/CrN revealed a typical columnar structure and B1-NaCl crystalline, no peaks of crystalline Si3N4 were detected. Among the multilayered TiSiN/CrN coatings, the multilayered coating with Λ =8.3 nm possessed higher hardness of 37±2 GPa, higher elastic modulus of 396±20 GPa and the lower residual stress of −1.60 GPa than the monolayered (Ti0.39Si0.07)N0.54 coating(−7.25 GPa). Due to the higher Cr/(Ti+Cr+Si) atomic ratio, the multilayered TiSiN/CrN with Λ =5.5 nm possessed the lowest friction coefficient. But the lowest of wear rate was obtained by the multilayered TiSiN/CrN with Λ =8.3 nm, because of higher H3/E⁎ 2 ratio of 0.323 GPa. The monolayered TiSiN possessed the highest wear rate of 2.87 μm2/min. Therefore, the mechanical and tribological property can be improved by the design of multilayered coating. [Copyright &y& Elsevier]

Abstract: Chromium carbide and chromium oxide coatings deposited by physical vapor deposition methods have been successfully applied in molding industries for their excellent tribological performances. In addition, nanocomposite coatings have recently attracted interest because of their high hardness, wear resistance, and good thermal and chemical stability. In this study, Cr–C–O/a-C nanocomposite coatings were synthesized by cathodic-arc evaporation with plasma enhanced duct equipment. A pure CO2 reactive gas was introduced to react with chromium to form Cr–C–O/a-C nanocomposite coatings during the deposition process. The atomic content ratio of O/(C+O) increased with increasing CO2 deposition pressure. A nanocomposite structure of coexisting Cr2O3 and Cr7C3 crystallites and amorphous carbon phases was found in the Cr–C–O/a-C coatings. The nanoindentation test revealed the nanocomposite Cr–C–O/a-C coatings with the highest atomic content ratio of O/(C+O) possessed the highest hardness of 23 GPa. [Copyright &y& Elsevier]

Abstract: Ti1−x Si x N coatings were synthesized by cathodic arc evaporation with plasma-enhancing filter duct, using Ti80Si20 alloy target as cathodes. Optical emission study revealed that excitation, ionization and charge transfer reactions of the Ti-Si-N plasma occurred during the Ti1−x Si x N deposition process. The chemical content of Si varied from 3.3 to 6.0at% in Ti1−x Si x N depending on the nitrogen partial pressure of the reaction chamber. All the Ti1−x Si x N coatings displayed a NaCl structure and a preferred (200) orientation parallel to the substrate surface. Among the studied Ti1−x Si x N coatings, the Ti1−x Si x N with 6at.% Si possessed the highest hardness of 45GPa and H 3/E*2 ratio of 0.527GPa, indicating the best resistance to plastic deformation. We found that the structure and mechanical properties of the Ti1−x Si x N films were correlated with the nitrogen pressure and silicon content of the coatings. [Copyright &y& Elsevier]

Abstract: Ternary TiCrN and nanocomposite TiCr(C,N)/amorphous carbon (a-C) coatings with different carbon contents (0–26.6 at.%) were synthesized by cathodic arc evaporation with plasma enhanced duct equipment. The structural, chemical, and mechanical properties of the deposited films were studied by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and nanoindentation measurement. The atomic content ratios of carbon/(Ti+Cr) and carbon/nitrogen increased with increasing C2H2 flow rate. A nanocomposite structure of coexisting metastable hard TiCr(C,N) crystallites and amorphous carbon phases was found in the TiCr(C,N)/a-C coatings, those possessed smaller crystallite sizes than the ternary TiCrN film. XPS analyses revealed the concentration of a-C increased with increasing carbon content from 8.9 at.% to 26.6 at.%. Exceeding the metastable solubility range of carbon within the TiCrN lattice, the carbon formed a-C phase in the deposited coatings. The nanocomposite TiCr(C,N)/a-C coatings exhibited higher hardness value of 29–31 GPa than the deposited TiCrN coating (26±1 GPa). It has been found that the structural and mechanical properties of the films were correlated with the carbon content in the TiCr(C,N)/a-C coatings. [Copyright &y& Elsevier]

Abstract: Monolayered AlTiN and Multilayered AlTiN/CrN coatings were synthesized by a cathodic-arc deposition process, using TiAl (with 50/50 and 33/67 at.%) and Cr elemental cathodes. The atomic ratio of Al/(Ti+Al) in the AlTiN coatings was reduced to 0.44 and 0.61, respectively, compared with the corresponding Ti50Al50 and Ti33Al67 cathode materials. The multilayered AlTiN/CrN films showed smaller crystallite size, larger lattice strain, higher hardness, higher residual stress, and better adhesion strength as well than the monolayered AlTi films. The multilayered Al0.35Ti0.22N0.43/CrN coating exhibited the highest hardness of about 38 GPa and the highest H 3/E*2 ratio value of 0.188 GPa, indicating the best resistance to plastic deformation, among all the coatings studied. [Copyright &y& Elsevier]

Abstract: Chromium doped a-C:H (Cr-C:H) films were synthesized by using a cathodic-arc activated deposition (CAAD) process with different bias voltage. Chromium plasma with intensive ion energies catalyzes the decomposition of hydrocarbon gas (C2H2), and induces the formation of hydrogenated DLC films with a mixture of sp2 and sp3 carbon bonds. The deposited carbon films consist of nanocomposite Cr-C:H films on top of a graded chromium nitride interlayer. It has been found that the structural and electrical properties of the films were correlated as a function of bias voltage. The formation of larger cluster of sp2 coordinated carbon atoms under high bias voltage results in a more enhancement of the electrical conductivity. The nature of the heterojunction is confirmed by the spreading resistance characteristics of the Cr-C:H film/CrN/Si junction showing a behavior dependant on the structure changes. [Copyright &y& Elsevier]

Abstract: Three kinds of diamond-like carbon (DLC) films, which contain different metals (Ti, Cr, Zr) and different interface designs, were deposited on biomedical titanium alloy (Ti–6Al–4V, ASTM F136) by using a cathodic arc evaporation system. Preliminary results showed that the DLC films are hydrogenated, amorphous and dense in structure. Scratch tests and Rockwell indentation tests reveal that the graded structures can improve the adhesion of DLC films. The Raman analyses showed that the Cr-containing DLC films possess lower I D/I G ratio, lower G-peak positions, and higher coating hardness. The pin-on-disk wear test in different environments (air and simulated body fluid) revealed that all the DLC films improve the wear performance of the substrates, and the wear coefficient is lower in simulated body fluid than that in air. In addition, the Cr-containing DLC films exhibited the lowest friction coefficient of 0.06 in simulated body fluid and 0.16 in air with the counterface of UHMWPE. Because of their dense structure, good adhesion and superior corrosion resistance in SBF, the Cr-C:H/CrN films exhibited significantly low friction in SBF. The ICP-MS analysis revealed the release of Cr ion is 2.22–10.03 ppm from the Cr-contained DLC films, which is less than that from Co–Cr–Mo alloy (106.17 ppm), showing that the Cr-containing DLC films meet the requirement of biomedical applications. The potentiodynamic test revealed that the corrosion resistance of the ASTM F136 titanium alloys is increased substantially by the metal-containing DLC coating. [Copyright &y& Elsevier]

Abstract: Metal plasma ion implantation has been successfully developed to improve the wear, corrosion, and physical properties of various engineering materials. In this study, Ti ions were implanted into electroless nickel coating at 100 keV and 5×1016–3×1017 ions/cm2 using a metal plasma ion implantation apparatus. Within the implanted region, the hardness of the electroless nickel coating is increased from 14 to 18–22 GPa by Ti ion implantation at doses of 1×1017–3×1017 ions/cm2. The electrochemical behavior of the Ti-implanted electroless nickel in a 3.5 wt.% NaCl solution was investigated by the potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS). The corrosion resistance of Ti-implanted electroless nickel was improved by the formation of chemically inert titanium oxides and Ti–Ni alloys in the ion-implanted layer, which leads to the increase of polarization resistances in the EIS analysis. At the dose of 3×1017 ions/cm2, the Ti-implanted electroless nickel possesses the best corrosion resistance due to the highest polarization resistance (3.05×105 Ω/cm2) and the lowest capacitance (1.5×10−5 F/cm2). Results of this study demonstrate the potential of metal plasma ion implantation in improving the corrosion resistance of the electroless nickel with enhanced mechanical properties. [Copyright &y& Elsevier]

Abstract: Multilayered TiAlN/CrN as well as monolayered CrN and TiAlN coatings were synthesized by cathodic arc evaporation with plasma enhanced duct equipment, using Cr and Ti50Al50 alloy cathodes. Optical emission spectra including atomic and ionized Ti, atomic Al and Cr, excited and ionized nitrogen (N2, N2 +, and N2 2+) revealed that excitation, ionization and charge transfer reactions of the Ti–Al–N and Cr–N plasma occurred during the multilayered TiAlN/CrN coating process. The preferred orientation was changed from (200) in CrN and TiAlN monolayered coatings to (111) plane in the multilayered TiAlN/CrN coatings. The multilayered TiAlN/CrN films had smaller crystallite size than the monolayered CrN and TiAlN films. The multilayered TiAlN/CrN coating with periodic thickness of 18 nm exhibited the highest H 3/E*2 ratio value of 0.193 GPa, indicating the best resistance to plastic deformation, among the studied CrN, TiAlN and multilayered TiAlN/CrN coatings. The multilayered TiAlN/CrN coatings also showed the best adhesion strength during scratch tests. It has been found that the structural and mechanical properties of the films were correlated with the multiple cathode design and nanolayer thickness. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped Cr–C:H/N films were synthesized by using a cathodic-arc activated deposition process. Chromium plasma with intensive ion energies catalyzes the decomposition of hydrocarbon gas (C2H2), and results in the deposition of amorphous carbon films. Nitrogen was introduced to form nitrogen-containing Cr–C:H/N films, which contained a mixture of sp2 and sp3 carbon bonds. The deposited carbon films consist of nanocomposite Cr–C:H/N films on top of a graded chromium nitride interlayer. It has been found that the structural and electrical properties of the films were correlated as a function of nitrogen doping. The nature of the heterojunction is confirmed by the spreading resistance characteristics of the Cr–C:H/N film/Si junction showing a behavior dependant on the nitrogen doping induced structure changes. With increasing nitrogen concentration, the increasing π states of sp2 hybridization results in a more pronounced enhancement of conductivity. [Copyright &y& Elsevier]