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This work investigates the influence of molecular iodine introduced as a charging agent into the suspensions based on the BaCe 0.8 Sm 0.19 Cu 0·01 O 3 (BCSCuO), BaCe 0·5 Zr 0·3 Y 0.1 Yb 0.1 O 3-δ (BCZYYbO) and BaCe 0.89 Gd 0.1 Cu 0·01 O 3-δ (BCGCuO) proton-conducting electrolytes at concentrations up to 1.0 g/L on their electrokinetic properties. The peculiarities of changes in zeta potential, pH, conductivity of the suspensions, the thickness and morphology of the coatings depending on the amount of iodine added are determined. It has been established that when the iodine concentration increases to 1 g/L, the electrical charge of the particles and the sign of the zeta potential undergo a reversal. Additionally, there is a natural decrease in the pH value towards the acidic side and a corresponding increase in the suspension conductivity. The research has demonstrated that in the suspension with a high iodine content (1 g/L), cathodic and anodic deposition can occur simultaneously under electrophoretic deposition (EPD) conditions at low voltage values (below 8 V). However, as the voltage increases, only cathodic deposition occurs. Therefore, the impact of altering the type of the EPD is threshold in nature relative to the magnitude of the EPD voltage. It has been shown that in order to practically implement EPD of ceramic coatings from modified suspensions of microsized powders of doped BaCeO 3 and BaCeO 3 –BaZrO 3 proton-conducting electrolytes, it is necessary to select a small amount of added iodine (0.1–0.2 g/L) to initiate a stable deposition process and to ensure continuity and uniformity of the coatings. This article discusses possible mechanisms of zeta potential inversion, electrophoretic mobility, and the EPD nature under conditions of high concentrations of iodide ions in the suspension bulk. The experiments have demonstrated the viability of the EPD process for the formation of a uniform BCSCuO coating (∼10 μm) on a supporting NiO–BCSCuO anode substrate using an iodine-modified suspension. This coating was subsequently sintered into a dense ceramic film at 1450 °C. In addition to the fundamental significance, the study results have implications for the practical use to improve and simplify the thin-film SOFC technology. [Display omitted] • Electrokinetic properties of proton-conducting electrolyte suspensions are studied. • The influence of iodine on zeta potential, pH of the suspensions is investigated. • The possible mechanisms of zeta potential inversion and the EPD nature are discussed. • EPD of thin-film doped BaCeO 3 and BaCeO 3 –BaZrO 3 electrolytes is implemented. • Dense BCSCuO film on porous NiO–BCSCuO anode by direct EPD at 1450 °C is obtained. [ABSTRACT FROM AUTHOR]

Bi 0.5 Na 0.5 TiO 3 -based ferroelectric materials with strong ferroelectricity and high Curie temperature have great application prospects in modern microdevices. In this paper, 0.92BNT-0.08BT ceramic coating was prepared by supersonic plasma spraying. The phase, microstructure, electrical properties and domain response of 0.92BNT-0.08BT ceramic coating were analyzed. The findings demonstrate that the 0.92BNT-0.08BT ceramic coating is without obvious structural defects and has a completely structure with good interface bonding. 0.92BNT-0.08BT ceramic coating has good electrical properties, the dielectric constant is 417, the dielectric loss is 0.3, and the remnant polarization is 16.6 μC/cm2. The piezoelectric force microscopy (PFM) results show that the 0.92BNT-0.08BT ceramic coating generally exhibits irregular and inhomogeneous striped nanodomains, with significant changes in amplitude and phase response under different electric fields. The results using switching spectroscopy-piezoresponse force microscopy (SS-PFM) show that the local piezoelectric coefficient (PR max) of the 0.92BNT-0.08BT ceramic coating reaches 754.3 p.m./V at a voltage of 20 V, and the ferroelectric domains exhibit a clear switching behavior. [ABSTRACT FROM AUTHOR]

Ceramic coating is a well-established method for enhancing the wear and corrosion resistance of metal components. Al 2 O 3 coating has been extensively utilized in industrial applications. However, existing ceramic coating processes often yield coatings that are relatively thin with limited wear and corrosion resistance. Furthermore, achieving efficient and high-quality coatings on complex metal surfaces poses significant challenges. The poor wettability between ceramics and metals further complicates the bonding at their interface. Chromium (Cr), a commonly used alloying element in steel, exhibits excellent interfacial wettability with iron (Fe), making it an ideal transition material for the Al 2 O 3 /Fe interface. In this study, complex Al 2 O 3 -based ceramic shells were fabricated via Binder Jetting. The Cr coating was coated on the surface of the shell, and then the Fe-based metal liquid was poured into the Al 2 O 3 -based ceramic shell to achieve metallurgical bonding at the Al 2 O 3 /Fe interface by temperature control treatment. The performance of the Al 2 O 3 ceramic matrix and the microstructure of the Al 2 O 3 /Fe interface with the Cr intermediate transition layer were investigated. The results indicate that when the solid loading of the Cr coating is 60 wt%, a uniform, and stable Cr coating can be formed on the surface of the sintered Al 2 O 3 -based ceramic. The bending strength of the Al 2 O 3 -based ceramic matrix increased from 113.79 MPa to 134.69 MPa. The Cr coating significantly improved the wettability between the Al 2 O 3 -based ceramic and the Fe-based metal, reducing the wetting angle from 98.9° to 78.4°. The interface between the Al 2 O 3 -based ceramic and Fe-based metal formed FeCr 2 O 4 after infusion, resulting in a well-bonded interface without significant cracks. [ABSTRACT FROM AUTHOR]

The durability of thermal barrier coatings (TBCs) is significantly influenced both by the ceramic top coat and the bond coat. In this study, novel YbGdZrO ceramic coats were deposited on the surfaces of three types of Cr-modified (Ni, Pt)Al bond coats via electron beam physical vapor deposition (EB-PVD) technique. These Cr-modified (Ni, Pt)Al bond coats were fabricated by magnetic sputtering Cr onto the (Ni, Pt)Al bond coats with varying sputtering times of 30, 60, and 90 min. The results indicates that the thickness of the Cr-modified layer increases with the extension of sputtering time. A short deposition time of 30 min is adequate for achieving an appropriate Cr content in the (Ni, Pt)Al bond coats, which ensures selective oxidation of Al element within the bond coat and further enhances the metallurgical interfacial bonding strength with the ceramic coat by adapting to the concentration gradient diffusion. However, as the sputtering time is extended to 60 and 90 min, α-Cr begins to form in the Cr-modified (Ni, Pt)Al bond coats, which negatively affects the oxidation resistance of the bond coat. Consequently, the thermal shock life of the TBCs samples is significantly reduced with increasing sputtering time. The longest thermal shock lifetime is obtained on the bond coat with Cr plating time of 30 min owing to a differing thermally grown oxide formation and failure mechanism. [ABSTRACT FROM AUTHOR]

Ceramic coatings have much potential for steel tubulars' protection against high temperature corrosion of gases and liquids, often containing abrasive solid particles, and to enhance their integrity in severe power generation, mineral and oil & gas production environments. Combining self-propagating high-temperature synthesis (SHS) with high-speed centrifugal process, alumina-based coatings were produced onto the inner surface of tubulars for these applications. According to the developed SHS batch formulation and the designed centrifugal device and process, well-consolidated composite ceramic layers with a thickness of 1.5–3 mm have been obtained. The developed SHS process does not create hazardous gases, and it takes ∼30 s for the ceramic phase formation. A high-level compaction due to centrifugal forces and a liquid phase sintering approach provided a dense gradient ceramic structure formed by oxide grains cemented by a glassy phase and bonded with a steel substrate through a thin iron layer. The coatings were successfully produced onto the inner surface of carbon and stainless steels' tubes of up to 12 ft-lengths and standard dimensions from 2 to 3/8″ to 7.5" OD. The coatings were tested, for the first time, in wear and high-temperature corrosive environments, e.g., in steam–H 2 S–CO 2 gases and molten salts, with encouraging results due to high contents of Al 2 O 3 and some other oxides and consolidated ceramic structure. They can be recommended for applications in high-temperature (900 °C and greater) corrosive environments and erosive flows. [ABSTRACT FROM AUTHOR]

In this study, magnetron sputtered carbothermic reduced iron boride (FeB) coatings were developed on grey cast iron (GCI) substrates at different substrate temperatures. The impact of substrate temperature on structural, mechanical, and corrosion behavior was examined for two FeB deposition scenarios: FeB coatings deposited at room temperature (RT) and at 500 °C substrate temperature. The evolution of phases and microstructure was studied using XRD and FESEM, respectively. The mechanical properties, creep, deformation behavior, and adhesion strength (scratch test) of the deposited coatings were investigated using nanoindentation at ambient temperature. The highest hardness and Young's modulus of 16 GPa and 231 GPa respectively, were achieved at 500 °C due to microstructural enhancement. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to evaluate the corrosion behavior of the coatings. The results show that substrate temperature strongly influences the surface morphology of the coatings, which in turn governs the mechanical and corrosion behavior of the FeB coating. The FeB-coated GCI at 500 °C substrate temperature showed higher resistance to scratching, better mechanical properties, and improved corrosion resistance which is attributed to the enhanced adhesive strength, refined microstructure, and formation of protective oxide layers of FeB on the surface of the coatings. [Display omitted] • FeB coatings have a hardness of 11.8 GPa, an elastic modulus of 165 GPa at RT, and 15.6 GPa and 231 GPa at 500 °C. • The FeB coating showed conformal cracking at RT and tensile cracking at 500 °C, indicating better adherence at 500 °C. • At 500 °C, the FeB coating displayed improved corrosion resistance and reduced corrosion current density. • EIS data revealed higher charge transfer resistance and a larger semicircle arc for the FeB coating at 500 °C compared to RT. [ABSTRACT FROM AUTHOR]

This research aims to broaden the scope of self-lubricating wear-resistant coatings for applications in diverse industries such as automotive, metallurgy, power, and aerospace. Employing laser cladding technology, we successfully fabricated high-performance self-lubricating ceramic composite coatings. A comprehensive investigation was conducted to understand the inhibitory effect of Cu on the thermal decomposition of MoS 2 , and the study systematically explored the relationship between powder composition, coating structure, and organizational properties. The mechanisms behind friction reduction and wear resistance were unveiled, shedding light on the formation of the MoS 2 self-lubricating protective film. Research findings reveal that during the laser cladding process, Cu and Ni undergo solid solution, resulting in the formation of the Cu–Ni alloy phase and crystal refinement. The MoS 2 aggregation area exhibits a fine dendritic structure, while the dispersion area showcases coarse dendritic and cellular crystals. The addition of Cu and MoS 2 influences the content of the M x C y phase and the thermal decomposition of MoS 2. The incorporation of Cu increases the average coating hardness, whereas MoS 2 addition decreases it; nevertheless, the Cu/MoS 2 coating hardness is enhanced by at least 6.4 %. Cu significantly improves the coating's wear resistance, with a relatively smaller impact on friction reduction. MoS 2 functions as a friction-reducing phase during wear, effectively preventing the peeling of hard phases and reducing the friction coefficient. Cu is uniformly distributed in the coating, experiencing solid solution strengthening, reducing adhesive region areas, and minimizing wear debris generation. MoS 2 , although unevenly distributed, forms intermittent lubricating films on the surface. The lubricating film of the Cu/MoS 2 coating remains stable, preventing mutual contact of the friction surface and concurrently reducing the friction coefficient and wear amount. While the study successfully prepared a self-lubricating ceramic coating with excellent wear resistance, some surface quality defects persist. Further optimization of the preparation method was achieved through ultrasound-assisted technology. [ABSTRACT FROM AUTHOR]

Yttrium‐stabilized zirconia (YSZ) plays a crucial role in thermal barrier coatings widely used to protect metallic components in gas turbine engines against high‐temperature combustion product gases and harsh environments. The thermal conductivity of these coatings is a critical parameter influencing the gas turbine design, performance, and service life. In this study, a laser temperature gradient method is utilized to measure the thermal conductivity of porous YSZ coatings. The method employs specialized laser energy delivery to create a one‐dimensional temperature gradient through the sample thickness, closely simulating the operational condition. This approach provides an effective, direct means to determine the thermal conductivity of high‐temperature heat‐resistant porous ceramic materials. [ABSTRACT FROM AUTHOR]

Confluent, a company based in Scottsdale, Arizona, has announced a partnership with ATI to invest over $50 million in expanding ATI's Nitinol melt and materials conversion infrastructure. This investment aims to meet the growing demand for medical Nitinol in various device markets. Furukawa Electric in Japan has announced the reorganization of its metal wire business to maximize synergy effects and increase corporate value. Liebherr-Aerospace in Germany has inaugurated a new building for surface treatment, equipped with state-of-the-art technology for coating processes. NEOTech, a leading provider of electronic manufacturing services, has acquired advanced 3D Computed Tomography equipment to enhance its process validation and failure analysis capabilities. Finally, Oerlikon has established an advanced coating technology center in New York to accelerate the development of high-temperature materials and coatings for the aerospace and gas turbine industries. [Extracted from the article]

Element additions in ceramic coatings played a positive role in electrochemical corrosion process, and Cr and C were doped into TiAlN coating by cathode arc ion plating. The effects of Cr and C additions on the structures and electrochemical properties of TiAlN coatings in 3.5 % NaCl solution were comparatively investigated, and the corrosion mechanisms were discussed with the density functional theory calculation. The results show that the particle size of TiAlCrN/and TiAlCN/TiAlN/TiN coatings are 31.6 and 25.7 nm, respectively, and the corresponding bonding strength is 16.18 and 37.93 N, respectively. The corrosion resistance of TiAlCrN/TiAlN/TiN coating is higher compared with the TiAlCN/TiAlN/TiN coating, which is attributed to the stronger oxidation reactions of TiAlCrN/TiAlN/TiN coating. The donor density of passive film on the TiAlCrN/TiAlN/TiN coating is lower than that on the TiAlCN/TiAlN/TiN coating, showing the minor susceptibility of TiAlCrN/TiAlN/TiN coating to corrosion. Moreover, the band gap and DOS of Cr 2 N and Cr 2 O 3 on the TiAlCrN/TiAlN/TiN coating are larger than those of Al 3 C 4 on the TiAlCN/TiAlN/TiN coating, presenting the stronger corrosion resistance. [ABSTRACT FROM AUTHOR]

A liquid-repellent and corrosion resistant surface was fabricated on AZ31B Mg alloy by the usage of CeO 2 and TiO 2 nanoparticles (NPs), plasma electrolyte oxidation (PEO) method, and subsequent surface modification. The whole process included two main steps: a) applying PEO with CeO 2 –TiO 2 NPs on AZ31B and b) decreasing surface energy by using a fluorinating agent. Elements that were present on the surface were investigated by XRD and EDS analyses. Surface morphology and its roughness were scrutinized by FESEM images and AFM tests, respectively. Contact angles (CA) of water and some oils (Ethylene glycerol and Glycerol) on the prepared surface were measured. CAs of water and ethylene glycerol were reported at 175.6° and 151.4°, respectively. Also, the corrosion behavior of the prepared surface was assessed by EIS and potentiodynamic polarization analyses. Results showed that the corrosion rate of the neat AZ31B decreased noticeably from 127.78 to 0.027 mpy for superamphiphobic PEO-NPs AZ31B. The prepared sample showed high mechanical durability, which was scrutinized by water floatation, abrasive with grit SiC paper, adhesive tape peeling, and bending tests. After immersion of the sample in 5 wt% NaCl solution for various hours, results showed that the prepared sample had a noticeable corrosion resistance stability. [Display omitted] • A durable superamphiphobic surface was fabricated on AZ31B. • The prepared surface showed a remarkable water and oil repellency. • A prepared superamphiphobic surface promoted noticeably the corrosion resistance of AZ31B. • A superamphiphobic surface showed brilliant corrosion resistance stability and mechanical durability. [ABSTRACT FROM AUTHOR]

The NiCoCrAlY and NiCoCrAlYHf bond layer alloy was prepared by vacuum melting, followed by the deposition of a ZrO2-7%Y2O3 (7YSZ) ceramic coating on its surface using atmospheric plasma spraying. The cyclic oxidation process of the coating was systematically investigated through extensive analytical equipment and first-principles calculations and compared with conventional NiCoCrAlY coatings. It is demonstrated that NiCoCrAlYHf coatings exhibit greater resistance to oxidation and peeling than NiCoCrAlY coatings when thermally cycled at 1050 °C in air. The reason for this difference is that Hf doping can reduce the growth rate of the thermally grown oxide (TGO). In addition, the formation of HfO2 in the TGO layer, which delays the phase transition of Al2O3, reduces the growth of internal stresses in the coating and improves the adhesion of the TGO layer and bond strength of the interface. As a result, Hf doping significantly increases the oxidation lifetime of the coating, approximately 8 times that of NiCoCrAlY. [ABSTRACT FROM AUTHOR]

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Surface ablation temperature and linear ablation rate are two crucial indicators for ceramic coatings under ultrahigh temperatures service, yet the results collection of such two indicators in the process is difficult due to the long‐period material preparation and the high‐cost test. In this work, four kinds of machine learning models are applied to predict the above two indicators. The Random Forest (RF) model exhibits a high accuracy of 87% in predicting surface ablation temperature, while a low accuracy of 60% in linear ablation rate. To optimize the model, the novel features are constructed based on the original features by the sum of the importance weights in the model. Thereafter, the importance of the newly constructed features increases significantly, and the accuracy of the optimized RF model is improved by 11%, exceeding 70% in accuracy. By validation with available data and experiments, the optimized model demonstrates precise predictions of the target variables. [ABSTRACT FROM AUTHOR]

Ceramic protective coatings applied to metallic interconnects play a vital role in solid oxide cells (SOCs) preventing interconnect degradation. In this study, uniform, dense, and crack-free single-layer coatings of MnCo 2 O 4 , Mn 1.7 CuFe 0.3 O 4 , and dual-layer coatings of MnCo 2 O 4 /Mn 1.7 CuFe 0.3 O 4 spinel are deposited onto complex-shaped metallic interconnect using electrophoretic deposition (EPD) method. The porosity of sintered MnCo 2 O 4 and Mn 1.7 CuFe 0.3 O 4 coatings in reduction treatment (1000 °C for 2h in H 2), followed by subsequent oxidation treatment (900 °C for 2h in air) is approximately 50% less than that of these coatings sintered in oxidation treatment (900 °C for 4h in air). The results indicate that the thickness of the sintered MnCo 2 O 4 , Mn 1.7 CuFe 0.3 O 4 single-layer, and MnCo 2 O 4 /Mn 1.7 CuFe 0.3 O 4 dual-layer coatings in reduction + oxidation treatments is 46.2%, 28.2%, and 23.1% denser, respectively, compared to sintered in oxidation treatment. Raman spectroscopy and Energy Dispersive Spectroscopy (EDS) analysis showed that in sintered dual-layer coatings subjected to reduction treatment followed by a subsequent oxidation treatment, exhibit a much more efficient interdiffusion processes throughout the thickness of the coating yielding the formation of a mixed (Mn, Cu, Fe, Co) 3 O 4 spinel, comparing to dual-layer coatings undergoing only oxidation treatment. The dual-layer spinel coatings of MnCo 2 O 4 /Mn 1.7 CuFe 0.3 O 4 present promising candidate for protective coatings on metallic interconnects. • A uniform and crack-free coating applied onto complex-shaped interconnects using the EPD method. • MnCo 2 O 4 /Mn 1.7 CuFe 0.3 O 4 dual-layer coating is a promising candidate for protective coatings. • Dual-layer coating densification in reduction + oxidation is higher than oxidation treatments. • Dual-layer coating provides higher protection against Cr diffusion than single-layer coating. [ABSTRACT FROM AUTHOR]

In this study, Al 2 O 3 –20TiO 2 (AT) and Cr 2 O 3 –3TiO 2 –5SiO 2 (CT) coatings were prepared by atmospheric plasma spraying (APS), The microstructure, phase compositions and corrosion behavior were studied comparatively. The results indicated that both coatings had layered structure, with an average surface roughness RA around 6 μm, an adhesive strength around 35 MPa, and a porosity around 4 %. The AT coating mainly composed of γ-Al 2 O 3 and α-Al 2 O 3 , and the CT coating composed Cr 2 O 3 respectively. Moreover, the AT coating exhibited better corrosion resistance than the CT coating. In artificial seawater, the corrosion process was strongly related to the porosity. The corrosion rate (based on the corrosion current density) of the two coatings showed a same trend which decreased first and then increased. It was thought that the blocking of early corrosion products in holes was helpful to delaying the progress of corrosion. In contrast, the later corrosion products would promote the formation and propagation of cracks, accelerating the corrosion. In the simulated environment with high pressure and hydrogen sulfide seawater, the corrosion process was strongly related to the porosity as well as the brittleness of the coatings. The corrosion rate (based on the weight loss) of the AT coatings still remained the same trend as it in the artificial seawater. However, the CT coating showed a continuously increasing corrosion rate, due to higher porosity and brittleness resulted in a large number of cracks under external stress, which offered corrosion channels. [ABSTRACT FROM AUTHOR]

In this study, inorganic-organic coatings composed of titanium dioxide (TiO 2) as the ceramic component and poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) as the polymer matrix, hybridized with nano-TiO 2 particles, were developed for protecting mild steel (MS) from corrosion. Prior to TiO 2 coating deposition, the MS substrates were pretreated with a bioinspired sub-layer of polydopamine to improve the surface coating adhesion, followed by uniform co-deposition of PVDF-HFP with varying concentrations of embedded nano-TiO 2. The inclusion of nano-TiO 2 further reinforces and densifies PVDF-HFP, providing added corrosion protection. The fabricated coatings were characterized by microscopy, spectroscopy, and diffraction technique, while the corrosion protection properties were evaluated by impedance, potentiodynamic polarization, salt spray, and cyclic corrosion tests. Results showed that both the PVDF-HFP matrix and TiO 2 contents had substantial effects on the coatings' thermal stability, hydrophobicity, and surface mechanical properties. The coatings also exhibited satisfactory corrosion resistance, with increased impedance modulus to roughly sixteen orders of magnitude for the TiO 2 -PVDF-HFP coating containing 0.5 g/L TiO 2 , relative to the untreated MS substrate. This result can be attributed to the low surface energy of PVDF-HFP, coupled with the dense structure and added physical barrier of nano-TiO 2. Overall, these hybrid polymer/ceramic coatings are poised to help design other highly resilient and hydrophobic surface coatings with durable protection against corrosion. [ABSTRACT FROM AUTHOR]

Photocatalytic membranes (PM) have been investigated as an antifouling strategy for membrane separation processes. Coating ceramic membranes with photocatalytic layers can provide a highly active surface capable of degrading foulants and smaller molecules improving the membrane's performance when the surface is irradiated by a suitable light. Nevertheless, the coating process often leads to pore blockage due to the formation or deposition of thick layers of photocatalyst on membrane surfaces, which modifies the original membranes' average pore size and reduces membrane permeability. A facile sol-gel dip coating process was used to produce PM without modifying the original surface morphology of alumina microfiltration membranes. A 3.7-fold increase in permeate volume after 90 min of permeation of an acetaminophen solution in continuous filtration mode under UV light (λ = 365 nm LED, 10W) using titania as photocatalyst compared to the bare alumina membrane without irradiation. Furthermore, fouling modelling proved a reduction in the fouling constant, while fouling mechanisms were not modified. Raman analysis showed 100% anatase formed on the membrane surface. Although membranes could remove up to 87% TOC for oily wastewater filtration, antifouling capabilities for this type of effluent were not observed for the photocatalytic membranes mainly due to fouling inside the pores and light attenuation due to the thick fouling layer on the membrane surface. [ABSTRACT FROM AUTHOR]

The wettability of the proppant is crucial in optimizing the flowback of fracturing fluids and improving the recovery of the produced hydrocarbons. Neutral wet proppants have been proven to improve the fluid flow by reducing the interaction between the fluid and the proppant surface. In this study, a lightweight amphiphobic proppant (LWAP) was prepared by coating a lightweight ceramic proppant (LWCP) with phenolic resin, epoxy resin, polytetrafluoroethylene (PTFE), and trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane (TMHFS) using a layer-by-layer method. The results indicated that the LWAP exhibited a breakage ratio of 2% under 52 MPa (7.5 K) closure stress, with an apparent density of 2.12 g/cm3 and a bulk density of 1.21 g/cm3. The contact angles of water and olive oil were 125° and 104°, respectively, changing to 124° and 96° after displacement by water and diesel oil. A comparison showed that the LWAP could transport over a significantly longer distance than the LWCP, with the length increasing by more than 80%. Meanwhile, the LWAP displayed notable resistance to scale deposition on the proppant surface compared to the LWCP. Furthermore, the maintained conductivity of the LWAP was higher than that of the LWCP after displacement by water and oil phases alternately. The modified proppant could minimize production declines during hydrocarbon extraction in unconventional reservoirs. [ABSTRACT FROM AUTHOR]

This study investigates the fabrication, microstructural characteristics and plasma resistance of Y–Al–Si–O (YAS) glass-ceramics coated on alumina ceramics. YAS frits were initially prepared using a melt-quenching method, then homogenously milled and coated onto alumina ceramics. The melt-coating process was conducted at 1650 °C for 1 h. The composition and microstructure of the glass frits and coatings were thoroughly characterized using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. These analyses revealed a dense microstructure with a polycrystalline structure predominantly composed of Y3Al5O12 (YAG) phase and a minor phase of Y2Si2O7. The YAS coatings on alumina revealed a dense layer with strong adhesion to the substrate. Subsequently, the coatings underwent C4F6/Ar/O2 plasma treatment for 1 h. Plasma exposure tests demonstrated that the YAS-coated alumina exhibited significantly better etching resistance compared to uncoated alumina, with minimal surface damage observed on the YAS coating, confirming its protective properties against plasma. The superior plasma resistance of YAS coatings is attributed to the predominance of its YAG phase. This research offers a more stable and cost-efficient solution for protecting ceramics in demanding plasma environments. [ABSTRACT FROM AUTHOR]

M-YTaO 4 is one of the most promising candidates for the next-generation thermal barrier coatings. However, the CMAS-induced degradation of M-YTaO 4 is still in dispute. This work comprehensively investigates the CMAS corrosion of M-YTaO 4 at 1300 °C which provides new insights into the corrosion mechanism. CMAS attacks M-YTaO 4 forming a thick recession layer and the main corrosion product is accurately confirmed to be (Ca 2-x Y x)(Ta 2-y-z Mg y Al z)O 7 solid solution. The recession layer presented a small difference in Young's modulus with M-YTaO 4. No delamination cracking occurred during the thermal cycling process indicating good reliability. In addition, grain boundary infiltration of CMAS is first revealed in M-YTaO 4. The results have corrected the misjudgment of the corrosion mechanism and CMAS infiltration process in previous studies which provides guidelines for the design of M-YTaO 4 thermal barrier coatings. [ABSTRACT FROM AUTHOR]

The high solar reflectance and good colour performance are requisite for the practical application of the colour-cool pigment. In this work, Ce-doped Yb 3 Al 5 O 12 and (Y, Yb) 3 Al 5 O 12 ceramic pigments were prepared by the sol-gel method. Both Ce3+ and Ce4+ ions coexist in the doped pigments. Due to the 4f→5d electron transition of Ce3+, the Ce-doped pigments have a selective absorption at around 400–520 nm, which is responsible for the yellow hue. The content of the Ce3+ ion determines the colour performance of the pigment. The size effect from the smaller Yb3+ ion results in an increased content of Ce3+ in the Ce-doped pigments, leading to an improved colour performance. The incorporation of Y3+ ion can effectively decrease the absorption at 975 nm, thereby enhancing the solar reflectance to 80.6 %, while maintaining good colour performance (Yb 0.7 Y 2.1 Ce 0.2 Al 5 O 12 , L* = 91.40, a* = -4.89, b* = 45.33). In a simulation experiment, the ceramic glaze coating based on the prepared pigment showed a temperature reduction of 5.2 °C compared to the commercial yellow pigment ceramic coating. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a multifunctional material with a myriad of potential applications, from high-power electronics to friction applications to power generation. Grafting preceramic polymers (PCPs) from SiC nanoparticles would create a platform for forming SiC via a polymer derived route that would have advantages over simple particle-PCP slurries and may enable new additive manufacturing inks or spreadable coatings with controlled rheology. Grafting PCPs directly on SiC powders would greatly improve dispersion of these particles and yield a single component system. Moreover, PCP-grafted-SiC would be a new addition to the burgeoning field of polymer grafted nanoparticles (PGNPs). Herein, SiC nanoparticles were surface-modified in a grafting-from polymerization reaction to create polycarbosilane (PCS) grafted SiC. Surface grafting was verified through a number of analytical techniques and the synthesized materials were pyrolyzed at 1600 °C. The PCS-grafted SiC retained 66 % of its pre-pyrolysis mass, representing a significant improvement over PCS-grafted silica nanoparticles from our previous work (20 wt% yield). In addition to an increased ceramic yield, the grafting of PCS to SiC also resulted in the formation of a SiC phase not present in the simple physical mixture of SiC nanopowder in PCS. This study demonstrated that PCP-grafted nanoparticles (GNPs) can be synthesized utilizing non-oxide nanoparticle cores with desirable rheology, opening possibilities for future ceramic inks and coatings. [ABSTRACT FROM AUTHOR]

In this study, the (AlTiCrNbTa)O 2 high-entropy ceramic coating was fabricated by laser cladding with squash presetting. Prior to laser cladding, the atmospheric plasma sprayed NiCoCrAlY and Al 2 O 3 –TiO 2 coatings were deposited on steel substrate. The microstructure and element distribution of the (AlTiCrNbTa)O 2 coating were investigated by XRD, EDS, SEM and TEM in detail. The results showed that the feedstocks with various structures were successfully transformed into the (AlTiCrNbTa)O 2 high-entropy ceramic with single rutile structure through laser cladding. The (AlTiCrNbTa)O 2 coating had a thick and compact structure, which consisted of mainly uniform solid solution in rutile structure and partially segregated Al 2 O 3 with dendritic crystals structure. The (AlTiCrNbTa)O 2 coating combined tightly with the Al 2 O 3 –TiO 2 coating, and presented a high level of hardness (17.7 GPa) and elastic modulus (298.7 GPa). [Display omitted] [ABSTRACT FROM AUTHOR]

To optimize the use of hollow‐core photonic crystal fibers (HC‐PCF), their cores are filled with an atomic gas for an ultra‐enhanced interaction with an incident laser beam in applications such as atomic vapor microcells. One challenge in these gas‐filled HC‐PCFs is to control the physiochemical interactions between the gas medium and the silica inner surface of the fiber core surround. In this work, thus, the processing of ceramic coatings on glass substrates by chemical solution deposition is focused on. Also, the successful implementation of an original coating procedure for a deposition inside hollow‐core fibers with complex microstructures is described. It is indeed possible to form a thin, dense, inorganic, and amorphous layer with a low thickness, low roughness, and high transparency. To obtain such a result, several parameters must be controlled, including the concentration of the solution, the technique and the deposition time, as well as the heat treatment undergone by the fiber. In particular, the selected aluminosilicate coatings, which are nonporous and present a 20–30 nm thickness, demonstrate a considerable improvement of the lifetime properties of the fibers filled with rubidium vapor, without modifying its original guiding properties. [ABSTRACT FROM AUTHOR]

In this study, we examined how current density, sodium phosphate concentration, and the addition of copper sulfate to the supporting electrolyte affect PEO coatings on pure titanium. The chemical composition, morphology, and optical behavior of PEO coatings were extensively analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV–Vis diffuse reflectance spectroscopy (DRS). With an increase in current density from 6 to 18 A/dm2, the coating's pore size enlarges and the rutile phase content within the coatings increases. The coating created at 12 A/dm2 shows the highest photocatalytic activity and triggers a unique three-stage behavior in the voltage-time diagram. Adding 4 g/l of CuSO 4 to the electrolyte resulted in the formation of an unwanted Cu-based precipitates, causing electrolyte instability. To stabilize it, potassium hydroxide was removed, and the base electrolyte concentration was adjusted. To address this issue, potassium hydroxide was eliminated from the supporting electrolyte. Subsequently, the concentration of the base electrolyte was optimized. Also, the synergistic influence of CuSO 4 addition (4 g/l) to the supporting electrolyte at different concentrations of 5, 10, and, 15 g/l of trisodium phosphate on PA was investigated. The superior photocatalytic performance of the optimum coating created in the electrolyte containing 5 g/l trisodium phosphate and 4 g/l CuSO 4 is attributed to its enhanced porous structure, along with the heterojunction between the anatase and rutile phases. These features significantly boost the available surface area and facilitate the efficient separation and transfer of photogenerated charge carriers. Ultimately, a mechanism for MB photodegradation was proposed based on the findings from Mott-Schottky analysis and DRS. [ABSTRACT FROM AUTHOR]

Next‐generation high‐brightness lighting faces a big challenge in developing laser‐drivable color‐converting materials with effective thermal management. Herein, a new material architecture of Al2O3‐Y3Al5O12: Ce3+ (YAG: Ce) transparent composite ceramics coated with Al film (TCC@Al) is proposed. The as‐prepared material shows the highest thermal conductivity (29.3 W m−1 K−1) among YAG: Ce‐related transparent ceramics (TC) ever reported owing to the combination role of short‐range thermal conduction of Al2O3 microcrystals and long‐range thermal conduction of Al film. Temperature‐dependent photoluminescence (PL) spectra and femtosecond transient absorption (fs‐TA) spectra evidence the importance of thermal management, whereby the luminescent loss of TCC@Al is only 8.92% at 450 K and is far smaller than TC counterpart (15.86%). Importantly, no obvious luminescence saturation is detected upon 20 W mm−2 blue laser irradiation and the inhomogeneous angular color distribution is suppressed by the scatter of Al2O3 microcrystals, yielding uniform white light with ultra‐high luminous flux (LF) of 4294 lm@20 W mm−2 and luminous efficacy (LE) of 215 lm W−1. As a consequence, the present TCC@Al‐converted laser‐driven lighting prototype exhibits much better optical performance than the commercial TC‐based one. [ABSTRACT FROM AUTHOR]

Ceramic and glass insulators as the first generation of insulators are often affected by flashover disturbance during operation. Ceramic insulators coated with semiconducting glaze (SCG) material are then proposed to improve the insulation performance due to warmer surface characteristics that can trigger evaporation on the surface. In this paper, a comparison of insulation performances of semiconducting glaze, ceramic, and glass insulators is discussed from both electrical and non-electrical aspects under various conditions. This comparison aims to distinguish the leakage current characteristics of each insulator during operation. Leakage current tests are conducted to obtain leakage current characteristics of each insulator under artificial conditions of no fog, clean fog, and salt fog. Furthermore, pollutants that are a mixture of NaCl (as equivalent salt deposit density (ESDD)) and kaolin (as non-soluble deposit density (NSDD)) are sprayed onto the insulator surface to see how the pollutant affects the leakage current characteristics of each insulator. The properties of measured leakage current waves are then analyzed, including the waveform, magnitude, and harmonic components. In addition, the non-electrical tests consist of hydrophobicity tests and thermal tests. In the hydrophobicity test, the contact angle formed by a water droplet on the insulator surface is measured, and in the thermal test, temperature differences on the insulator surface before and after voltage applications are compared. The experiment results show that the SCG insulator has a larger leakage current than the other insulators, while the leakage current magnitude of the ceramic and glass insulators is similar. The surface temperature of the SCG insulator is also higher than that of the other insulators due to a larger leakage current. Additionally, the SCG insulator shows better hydrophobicity compared to the other insulators, where all types of insulators show decreased contact angle when pollutants are given. [ABSTRACT FROM AUTHOR]

The surfaces of ceramic products are replete with numerous defects, such as those that appear during the diamond grinding of sintered SiAlON ceramics. The defective surface layer is the reason for the low effectiveness of TiZrN coatings under abrasive and fretting wear. An obvious solution is the removal of an up to 4-µm-thick surface layer containing the defects. It was proposed in the present study to etch the layer with fast argon atoms. At the atom energy of 5 keV and a 0.5 mA/cm2 current density, the ions were converted into fast atoms and the sputtering rate for the SiAlON samples reached 20 μm/h. No defects were observed in the microstructures of coatings deposited after beam treatment for half an hour. The treatment reduced the volumetric abrasive wear by five times. The fretting wear was reduced by three to four times. [ABSTRACT FROM AUTHOR]

In this work, to establish the oxidation resistance for graphite in the air atmosphere with temperatures ranging from 700 to 1000 °C, an innovative multi-component, dual-layer coating was developed. The coating consists of two layers with a total thickness of around 250 μm. The first layer was consisted of B2O3 with SiO2 and ZnO, while the second layer included SiC with silicon as an additive. Through scanning electron microscopy (SEM) images and elemental maps, alongside heat treatment experiments at 1000 °C, which resulted in only a 6% weight loss, it was evident that the coating was effectively applied and performed exceptionally well. Moreover, cyclic heat treatment experiments confirmed the coating's durability and thermal stress resistance, with minimal weight reduction results. Applying these coatings is uncomplicated, and the materials are readily available, ensuring cost-effectiveness. [ABSTRACT FROM AUTHOR]

A novel approach to the fabrication of thin-film supported metal oxide membranes was investigated. Nanocoatings were obtained by the condensed layer deposition of TiO2 on tubular microporous supports, applying multiple consecutive layers of TiO2/polyaniline. The surface, cross-sectional structure, and morphology of the materials were investigated by electron microscopy. Their membrane-related properties were explored by permeability measurements, rejection, and fouling analysis, using polyethylene glycol (PEG) as test molecules. The SEM images showed that TiO2 was successfully deposited on the surface, creating a layer with partial coverage of the support after each layer was deposited; consequently, the permeability of the membranes decreased gradually. Overall, the results of the flux and permeability of the membranes confirmed the coating. The transmembrane pressure (TMP) increased with each coating layer, while the rejection of the membrane showed gradual improvement. [ABSTRACT FROM AUTHOR]

The erosion process of a 4 μm monolayer CrN coating deposited on 316L stainless steel due to cavitation was investigated using finite element analysis (FEA). To estimate load parameters from cavitation pit geometry resulting from high impact velocity and high strain rate, the explicit dynamic solver was employed. Water microjet impacts at velocities of 100, 200 and 500 m/s were simulated to recreate different cavitation erosion intensities observed in the experiment. The resulting damage characteristics were compared to previous studies on uncoated 316L steel. The relationship between impact velocity and postimpact geometry was examined. Simulations revealed that only impact at 500 m/s can exceed the maximum yield stress of the substrate without penetrating the coating. Subsequent impacts on the same zone deepen the impact pit and penetrate the coating, leading to direct substrate degradation. The influence of impact velocity on the coating degradation process is discussed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to investigate the influence of varying concentrations of nano-SiO2 particle doping on the structure and properties of the micro-arc oxidation (MAO) coating of 7075 aluminum alloy. This research aims to provide novel insights and methodologies for the surface treatment and protection of 7075 aluminum alloy. Design/methodology/approach: The surface morphology of the MAO coating was characterized using scanning electron microscope. Energy spectrometer was used to characterize the elemental content and distribution on the surface and cross section of the MAO coating. The phase composition of the MAO coating was characterized using X-ray diffractometer. The corrosion resistance of the MAO coating was characterized using an electrochemical workstation. Findings: The results showed that when the addition of nano-SiO2 particles is 3 g/L, the corrosion resistance is optimal. Originality/value: This study investigated the influence of different concentrations of nano-SiO2 particles on the structure and properties of the MAO coating of 7075 aluminum alloy. [ABSTRACT FROM AUTHOR]

Protective ceramic coatings are frequently the most common solutions for problems like corrosion and wear. Polymer derived ceramics technology is suitable for the preparation of ceramic coatings by pyrolysis in a furnace but requires high temperatures for the ceramization. To overcome this restriction a Nd:YVO 4 laser (λ = 1064 nm) as energy source was used to process a novel ceramic coating system composed of an organosilazane with zirconia and alumina particles specially to protect magnesium. The resulting dense ceramic coating with a thickness up to 20 µm exhibits very good adhesion (25.9 ± 2.7 MPa) to the magnesium substrate, exceptionally high hardness (19.79 ± 1.90 GPa), an outstanding thermal shock stability but also a low coefficient of friction (0.21 ± 0.02) and a very good wear protection towards a SiC counter body. Furthermore, the coating protects the magnesium substrate effectively against corrosion (5 wt% aqueous NaCl solution). [ABSTRACT FROM AUTHOR]

An amorphous SiO 2 ceramic coating with a thickness of ∼72 μm is prepared within 13 min in organo-silicon electrolyte, which is stable in strong acid solutions, reducing corrosion current density of 6061 aluminum alloy by 3 orders of magnitude. With the aim to reveal influence of the electrolyte concentration, NaOH content and additive (NaPO 3) 6 on microstructure and corrosion resistance of the coatings, SEM/EDS, XRD, electrochemical tests were used to characterize their thickness, surface and cross-sectional morphology and structure, and corrosion performance prepared by using different electrolytes under the same electric control parameters. The results show that they significantly affect the surface morphology, structure and corrosion resistance of the coatings. Dilution of the electrolyte results in a significant decrease in coating thickness and surface porosity, reduction of NaOH content leads to coating thinning, increased porosity but reduced pore size. Coatings with lower porosity or smaller pore sizes are more effective in resisting corrosive media penetration for long term immersion. Whereas, the additive (NaPO 3) 6 promotes coating thickening, widening of the transition layer, which helpfully improves the corrosion resistance of the coating. [Display omitted] [ABSTRACT FROM AUTHOR]

Electrochemical micromachining is promising technique used to machine metal matrix composites and hard to cut materials. In this research mixed L18 Orthogonal array experiments are used to along with 30 vol% of ethylene glycol mixed sodium nitrate electrolyte. The tool electrode is coated with ceramic coating whose diameter is 360 µm and Al7075 + 10 vol%B4C metal matrix composites of thickness 500 µm is used as a workpiece. The experiments are optimized using grey relational analysis and most significant factor is found using Analysis of variance (ANOVA). As per the Grey relational Analysis (GRA) the optimal combination is 30 vol% of ethylene glycol,voltage of 9 V,duty cycle of 70% and electrolyte concentration of 35 g/L. As per the ANOVA, the most promising factor is electrolyte concentration which shows 46.36%. The Artificial Neural Network (ANN) model prediction value is 0.1675 and 1.1400 which is very close to GRA optimized values of machining rate and surface corrosion factors, ie 0.1667 and 1.1395 respectively. [ABSTRACT FROM AUTHOR]

In the existing literature, there are few studies on the effect of deposition bias on the tribological properties of carbon-doped high-entropy alloy coatings. In order to further study the effect of the deposition bias on the properties of coatings, (AlTiVCrNb)CxNy coatings were deposited via unbalanced RF magnetron sputtering. The microstructure and tribological properties of carbon-doped high-entropy alloy ceramic coatings under different deposition biases were studied. The composition, morphology, crystal structure, and chemical morphology of each element of the coating were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The hardness, elastic modulus, friction, and wear properties of the coating were further characterized using a nanoindentation instrument, reciprocating sliding friction, a wear tester, and a white light interferometer. The coating density reached the optimal level when the deposition bias value was 90 V. The hardness and elastic modulus of the (AlTiVCrNb)CxNy coating increased first and then decreased with an increase in deposition bias, and the maximum hardness was 23.98 GPa. When the deposition bias was 90 V, the coating formed a good-quality carbon transfer film on the surface of the counterbody due to sp2 clusters during the friction and wear process. The average friction coefficient and wear rate of the (AlTiVCrNb)CxNy coating were the lowest, 0.185 and 1.6 × 10−7 mm3/N·m, respectively. The microstructure, mechanical properties, and tribological performance of the (AlTiVCrNb)CxNy coating were greatly affected by the change in deposition bias, and an (AlTiVCrNb)CxNy coating with excellent structure and friction properties could be prepared using graphite co-sputtering. [ABSTRACT FROM AUTHOR]

The microstructure, mechanical performance, and tribological properties of SiC ceramic coatings prepared via atmospheric plasma spraying (APS) and chemical vapor deposition (CVD) method were compared to provide good anti-wear protection for carbon/carbon composites. The surface morphology of the APS-SiC coating was characterized as having a porous structure, whilst the CVD-SiC coating presented with many pyramidal-shaped crystals constituting the surface. The APS-SiC coating consists of a dominating SiC phase and a small fraction of the Si phase, while the XRD pattern of the CVD-SiC coating mainly consists of the SiC phase. The dense crystalline microstructure of the CVD-SiC coating made it possess a higher hardness and Young's modulus at 31.0 GPa and 275 GPa, respectively. The higher H/E and H3/E2 parameters of the CVD-SiC coating implied that it exhibited better plastic resistance, which is also beneficial for anti-wear properties. The scratch test reflected the critical loads of the spallation of the APS-SiC coating and CVD-SiC coating, which were evaluated to be 25.9 N and 36.4 N, respectively. In the tribological test, the friction coefficient of the APS-SiC coating showed obvious fluctuations at high load due to damage to the SiC coating. The wear mechanism of the APS-SiC coating was dominated by abrasive wear and fatigue wear, while CVD-SiC was mainly dominated by abrasive wear. The wear rate of the CVD-SiC coating was far below that of the APS-SiC coating, suggesting the better wear-resistance of the CVD-SiC coating. [ABSTRACT FROM AUTHOR]

Atmospheric plasma spraying (APS) allows deposition of ceramic coatings on metallic substrate, significantly increasing the wear resistance of the component. Coating's microstructure and consequently its properties, depend on heat treatment of the feedstock particles. This property can be controlled by process parameters, especially electric power and spray distance. On the other hand, some plasma torches allow introducing another variable, an injection mode, which could be realized in external or in internal way. In the presented research, wear resistance of Al2O3+13 wt.% TiO2 coatings deposited under various values of spray distance and different injection modes were examined using ASTM G-99 procedure. The impact of spraying parameters on the coating's microstructure was established and connected to the functional properties of the manufactured deposits. Observed differences indicated influence of injection mode and spray distance value. Coatings deposited with internal feedstock injection exhibit lower porosity and slightly higher hardness than these made with external injection mode. In terms of wear resistance for both spray distance the wear factor was lower for internal injection system. Obtained results confirmed assumed thesis, that internal injection mode improves heat treatment and consequently ameliorate wear performance of plasma sprayed alumina-titania coatings. [ABSTRACT FROM AUTHOR]

Al-Li alloys have been widely applied in aircraft structural component and shell material. However, Al-Li alloys are prone to corrosion failure, which leads to a considerable safety risk in the aerospace field and greatly limits their industrial application. Herein, a simple, low-cost, and large-scale air-spraying technique is developed for the preparation of an alumina-based ceramics coating with enhanced corrosion resistance and anti-icing behavior. The results show that the static contact angle of the as-prepared coating is 157.2 ± 0.4°, and the rolling angle is only 9.8°, suggesting a super-hydrophobic surface. Meanwhile, the electrochemical corrosion potential of the coating is 70 mV higher than that of the substrate, and the corrosion current density of the coating also decreases by 1 order of magnitude, indicating a significantly improved corrosion resistance. In addition, the fabricated super-hydrophobic coating also shows excellent anti-pollution and anti-icing characteristics. This work provides positive guidance for expanding the application of hydrophobic coating in the aerospace industry, especially in some complex corrosion, icing, and pollution environments. [ABSTRACT FROM AUTHOR]

In this study, a NiCr/YSZ coating was applied to a γ-TiAl surface using multi-arc ion plating technology to enhance its high-temperature performance and explore the mechanisms of high-temperature oxidation and thermal corrosion. The thermal corrosion properties of the γ-TiAl matrix and NiCr/YSZ coating were investigated at 850 °C and 950 °C using a constant-temperature corrosion test in a 75% Na2SO4 + 25% NaCl mixture. The results indicate that after 100 h, the thermal corrosion weight gain of the coating samples was 70.1 mg/cm2 at 850 °C and 118.2 mg/cm2 at 950 °C. At these temperatures, sulfide formation on the surface increases, leading to a loose and porous surface. After 100 h of high-temperature corrosion at 850 °C, the primary oxidation product on the surface of the coating was tetragonal-ZrO2. At 950 °C, Y2O3, which mainly acts as a stabilizer in YSZ, reacted with Na2SO4, resulting in the continuous consumption of Y2O3. This reaction caused a substantial amount of tetragonal-ZrO2 to transform into monoclinic-ZrO2, altering the volume of the ceramic layer, which induced internal stress, crack propagation, and minor spallation. A continuous and dense internal thermally grown oxide (TGO) layer effectively impeded the diffusion of molten salt substances and oxygen, thereby significantly improving the thermal corrosion resistance of the thermal barrier coating. [ABSTRACT FROM AUTHOR]

In the present work, transition metal‐containing preceramic silicon polymers were synthesized via chemical modification of a commercially available organopolysilazane with Hf and Ta amido complexes as well as with borane dimethyl sulfide complex. The incorporation of transition metals into the polymer structure, their influence on ceramization and processability were thoroughly investigated. Moreover, the prepared preceramics were coated onto silicon wafers via spin coating and converted into crack‐free, amorphous SiHfTa(B)CN‐based ceramic coatings with excellent adhesion to the substrate. The composition of the ceramic coatings was investigated via X‐ray photoelectron spectroscopy (XPS) and their high‐temperature behavior was studied via oxidation tests performed at 1100 °C. Moreover, a thermal cycling procedure to temperatures above 1250 °C with rapid heating and cooling rates (i.e., in the range of 100–120 K s−1) was applied to the ceramic coating, which showed no damage even after ten thermal cycles, indicating their outstanding performance and their potential for use as environmental barrier coatings at high temperatures. [ABSTRACT FROM AUTHOR]

The structure design and optimization of multilayer coatings, which are utilized to surmount the trade-off between hardness and toughness, has been a current hot topic in the field of hard ceramic coatings. Herein, multi-layered TiSiN/AlCrN coatings with a constant and gradient sublayer thickness (Λ, modulation periods) ranging from 20 to 3.8 nm were prepared by the cathodic arc ion plating. The microstructure, mechanical properties, residual stress, and fracture toughness of four gradient structures were investigated systematically. All coatings exhibit a typical FCC crystal structure. In the coating with a monotonous decrease of modulation period (single gradient periodic decreasing structure, G2), the interface between the TiSiN layer and the AlCrN layer transformed from a partially semi-coherent interface at the bottom layers of Λ = 20 nm, to a fully coherent interface at the top layers of Λ = 3.8 nm. The coating with dual-gradient structures (modulation period increases first and then decreases, V2) demonstrated the highest hardness (37.6 ± 1.0 GPa), H/E* and H3/E*2 ratios (0.087 and 0.28 GPa), and bonding strength (75.3 N), as well as lowest friction coefficient (0.34) and wear rate (6.7 × 10−6 mm3/N m). The remarkable resistance to damage and toughness displayed by the V2 structure could be ascribed to its intrinsic capacity for effectively alleviating stress concentration and accommodating incompatibilities during the plastic deformation process. This work offers insights into employing gradient architecture design to enhance the strength and toughness of coatings. [ABSTRACT FROM AUTHOR]

Plasma spraying is a prospective method frequently employed because of its increased effectiveness in ceramic coatings. Optimizing process parameters is necessary to maximize the coating performance. This study employed response surface methodology (RSM) to investigate the impact of process variables, including current, powder feed rate, and standoff distance, on the porosity and corrosive wear loss of Cr3C2+8YSZ composite coating. Experiments were done using the central composite design method, and quadratic regression models were created for the responses based on the completed trials. All parameters are observed to be most significant as the obtained p-value is under the threshold of 0.05 as per the analysis of variance (ANOVA) calculations. The optimal plasma spray process parameters were determined to be 500 A of current, a powder feed rate of 46gm/min, and a standoff distance of 3 inches for the expected lowest corrosive wear loss of 0.000025mm/year and a reduced area percentage porosity value of 0.93. [ABSTRACT FROM AUTHOR]

The tribological performance of the tungsten carbide substrate (WC‐Co), improved by ceramic coatings, is still being reported in new studies that have been carried out to date. It has become a hot research topic that are widely applied in hard material research, especially in the tools manufacturing fields. This study was conducted to investigate the wear characteristics of a commercial cemented carbide tool (WC‐Co) coated with a physical vapor deposition chromium‐vanadium nitride film (CrVN), followed by a boriding process as a final thermochemical treatment. Tested in dry sliding contact against an alumina ball as a static partner, the tribological responses of the specimen were analyzed and compared with an uncoated specimen. Friction coefficients, calculated from volume loss, were around .58 for all specimens except the uncoated specimen at 10 N of applied load. Wear scar analyses revealed the occurrence of several wear mechanisms that is polishing, oxidation, wear debris formation, surface binder removal, grain fragmenting, and grain pull‐out. [ABSTRACT FROM AUTHOR]

In this study, a high-strength alumina ceramic reinforced by a coating composed of 25wt% AlN and 75 wt% Al2O3 (labeled as ACRA-CoA) was fabricated using the spark plasma sintering (SPS) method. The thermal expansion coefficient difference between the coating and the substrate generates significant residual compressive stress in the coating during sintering cooling process, which acts protectively on the ceramic substrate, hindering crack propagation and enhancing mechanical strength. As a result, ACRA-CoA demonstrates an impressive flexural strength of 586.4 ± 70.5 MPa, marking a substantial 65.7% increase compared to conventional alumina's strength of 353.9 ± 20.5 MPa. Additionally, the doped aluminium nitride in the coating significantly improves its thermal properties, for example, at 25 °C, the thermal conductivity of ACRA-CoA is 28.93 W∙m − 1 ∙K − 1, which is 46.2% higher than that of conventional alumina, and the thermal diffusion coefficient increased by 43.5% to 0.089 mm − 2 ∙S − 1, while the coefficient of thermal expansion is 8.5 × 10 − 6 K − 1 [ABSTRACT FROM AUTHOR]

In this work, Al 2 O 3 –GdAlO 3 (GAP) amorphous ceramic coatings were prepared via plasma spraying. A novel method of regulating spray powder phase compositions was provided to obtain the different amorphous phase contents in Al 2 O 3 –GAP coatings. The α-Al 2 O 3 /c-Gd 2 O 3 and α-Al 2 O 3 /GAP sprayable powders were individually applied to deposit the coatings, namely Coating 1# and Coating 2#. Their amorphous phase contents were 91.8 wt% and 55.4 wt%, respectively. X-ray diffraction, scanning electron microscope, electron backscattered diffraction, X-computed tomography, atom probe tomography and micropillar compression tests combined with finite element method were applied to analyze microstructural features and mechanical performance of the coatings. The results showed that Coating 2# possessed higher compressive strength (3.42 GPa) and greater compression plasticity (21.8 %) than Coating 1#. Compared with nearly 40 amorphous materials, Coating 2# had an excellent compression plasticity, which was better than almost all amorphous alloy materials, showing extremely attractive engineering application potential. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive analysis of the morphology, mechanical properties, erosion resistance, and machine learning modeling of Si 3 N 4 +TiC + VC and CrNi based ceramic coatings deposited via plasma spraying. The cross-sectional morphology analysis revealed good mechanical interlocking between the coatings and the substrate, with pores predominantly observed in the Si 3 N 4 +TiC + VC coating. The coating thicknesses were measured as follows: 260 μm for Si 3 N 4 +TiC + VC, 243 μm for Si 3 N 4 +TiC + VC blended with CrNi, and 232 μm for pure CrNi coating. Mechanical characterization showed that microhardness values ranged from 1933 HV for Si 3 N 4 +TiC + VC coating to 499 HV for pure CrNi coatings. Slurry erosion tests demonstrated that pure Si 3 N 4 +TiC + VC coating exhibited superior erosion resistance at 90° impingement angle compared to other coatings. Additionally, a rigorous evaluation of over 20 machine learning regression models revealed that Gaussian Process Regressors and Artificial Neural Network (ANN) with a layer size of 20, displayed satisfactory performance in modeling mass loss prediction. The erosion mechanisms observed in the coatings provided valuable insights into their response to slurry erosion, highlighting the influence of coating composition and impingement angles. The findings underscore the potential of Si 3 N 4 +TiC + VC ceramic coatings to enhance the erosion resistance of stainless steel, offering promising applications in various industries. [Display omitted] [ABSTRACT FROM AUTHOR]

Thermal barrier coatings (TBCs) are effective protective and insulative coatings on hot section components of turbine engines. The quality and subsequent performance of the TBCs are strongly dependent on the adhesion between the coating and the metal substrate. The adhesion strength of TBCs varies depending on the substrate materials and coating, the coating technique used, the coating application parameters, the substrate surface treatments, and environmental conditions. Therefore, the roughness of the substrate surface has a significant effect on the performance of the TBC system. In this work, the roughness and microstructure of the 7YSZ (7 wt.% yttria-stabilised zirconia) top coat under different bond coat roughness treatments were studied. The purpose of this paper was to investigate the influence of the roughness of the bond coat on the adhesion of 7YSZ TBCs prepared by the electron beam–physical vapour deposition (EB-PVD) process. The VPA (vapour phase aluminium) bond coat was deposited on Inconel 718 nickel superalloy substrate using the above-the-pack technique. The ceramic top coat was applied to the bond coat using the EB-PVD process. The dependence between the TBC coating roughness and the bond coat roughness was determined. Adhesion strength measurements were performed according to the ASTM C 633 standard test method. The highest adhesion value observed in the tensile adhesion tests was 105 MPa. However, it was not determined whether the surface roughness of the bond coat affects the adhesion of the 7YSZ top coat. [ABSTRACT FROM AUTHOR]