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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]

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]

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]

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]

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: 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]

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]

The high potential of the protective coatings for metal machining applications using the physical vapor deposition (PVD) processes is one to be valued, and will accelerate development of the multicomponent coating design and increase the cutting efficiency. In this study, nanostructured AlTiCrMoN coatings in a multilayered structure were fabricated using cathodic-arc deposition (CAD). Controlling the cathode current of both CrMo and AlTi alloy targets in a nitrogen environment, multilayered AlTiN/CrMoN coatings were deposited. The AlTiN and AlTiN/CrMoN multilayered coatings exhibit a face-centered cubic (fcc) structure with columnar morphologies. The highest hardness of 35.6 ± 1.5 GPa was obtained for the AlTiN coating; however, the H3/E*2 and H/E* values were the lowest (0.124 and 0.059, respectively). The multilayered AlTiN/CrMoN coatings possessed higher H3/E*2 and H/E* values of up to 0.157 and 0.071, respectively. The present study investigated the cutting performance of end mills in the milling of SUS316L stainless steel. The cutting performance was evaluated in terms of cutting length and tool wear. Because of high resistance to adhesive and abrasive wear, the end mills coated with multilayered AlTiN/CrMoN showed less flank wear than monolithic AlTiN. The introduction of CrMoN sublayers improved the cutting tool life of AlTiN. [ABSTRACT FROM AUTHOR]

The extension of tool life is a crucial goal for heat resistant forming tools. Therefore, the industry is interested to reduce the friction and wear for these tools. The employment of metals, polymeric composites, and ceramics as solid lubricants increases the production as well as maintenance costs. Thus, the thin film technology and especially new self-lubricating coatings will become increasingly important. Titanium aluminum vanadium nitride as a self-lubricating coating has a high potential to improve the tribological behavior of heat resisting tool surfaces and has good mechanical properties such as a high hardness (more than 40GPa). In this study, TiAlVN coatings were deposited on HS6-5-2C high speed steel substrates by using a magnetron sputtering system. After annealing at 650°C, a V2O5 (Magnéli phase) which adds self-lubricating qualities to the coatings could be detected in the TiAlVN layer. Due to the influence of adhesive and cohesive damage processes, resulting from the residual stress behavior in the layer close to the substrate area, it is critical to measure residual stresses in order to increase the wear resistance. In addition to the phase analyses, residual stress measurements were investigated by means of x-ray diffractometry as well. An experimental method, based on the traditional sin2ψ-method and utilizing a grazing-incidence diffraction geometry was used in order to enhance the irradiation volume of thin film samples. This resulted in a higher intensity for high-angle Bragg peaks than for the Bragg–Brentano geometry. Furthermore, the mechanical and tribological properties of the TiAlVN coatings were characterized at elevated temperatures. The required results were provided by a high temperature ball-on-disk device and a nanoindenter. [ABSTRACT FROM AUTHOR]