bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Nanostructured YPSZ Coating Microstructure on the Thermal Conductivity
Authors: Wang Q.S. , Wang F.C. , Liu Y.B. , Ma Z. 
Published: September 2022

Abstract
6~8% Y2O3 partially stabilized ZrO2 (YPSZ) nanostructured coatings were fabricated by atmospheric plasma spraying (APS). The fractured cross-section morphologies of the samples were observed by scanning electron microscopy (SEM). The thermal conductivities of free-standing pure nanostructured YPSZ coatings samples were determined using the laser flash technique. Specific heat was measured through a differential scanning calorimeter. The results showed that there is a great difference between the fractured cross-section microstructure of nanostructured and conventional zirconia coatings. The nanostructured one exhibits a bimodal distribution of microstructure, viz. directional crystal and isometric crystal structure. Plasma spraying parameters have a significant effect on the microstructure through changing the content of isometric crystal structure in the coating. The thermal conductivity decreased with increased isometric crystal microstructure content. The thermal conductivity can be lowered up to 60%.
Durability of HVOF Sprayed MoB/CoCr Coating on the 316L Stainless Substrate in Molten 55%Al-Zn-1.5%Si Bath
Authors: Lv H.P. , Wang J. , Zhai C.S. , Li F. , Sun B.D. 
Published: September 2022

Abstract
In order to develop protective coatings for sink rolls in continuous hot-dip galvanizing, a sprayed MoB/CoCr cermet coating was formed on a 316L stainless steel by the HVOF spraying process and its durability in the molten 55%Al-Zn- 1.5%Si bath (923 k) has been investigated by SEM and EDS. The immersion test revealed that the MoB/CoCr coating has much higher durability (640 hours) in 55%Al-Zn-1.5%Si bath than the conventional sprayed coatings (120 hours), such as WC-Co, WC/Co/Cr and ceramics. It was found that the failure of MoB/CoCr coating is mainly caused by the mismatch of coefficient of thermal expansion (CTE) between the top coating and the substrate. The failure procedure is that first crack is generated because of heat stress, then the crack proceeds and causes scaled delamination, at the same time molten Al-Zn will enter into cracks and/or Al-Zn reaches the undercoat and/or substrate, finally molten Al-Zn dissolves the substrate.
Thermal Shock Behavior of the Supersonic Plasma Sprayed CeO2-Y2O3-ZrO2 Functionally Graded TBC
Authors: Han Z.H. , Wang H.J. , Guo Y.B. 
Published: September 2022

Abstract
A functionally graded thermal barrier coating (FG-TBC) of CeO2-Y2O3-ZrO2/NiCoCrAlY was prepared using a recently developed supersonic plasma spray (S-PS) system. The system had dual powder feed ports through which the metal alloy powders were fed into the lower temperature region of the plasma plume, to prevent over oxidation, and the ceramic powders were fed into the high temperature region, to produce complete melting. Such an approach enabled fine configurations having a continuously graded composition transition to be obtained. The thermal shock testing of the deposited samples with 1mm thick FG-TBC system on Ni-based alloy substrates was performed using an in-house-designed multi-functional rotational thermal shock tester. In this tester, the heating-cooling curves and surface morphology of tested specimens can also be observed by a microscope with a CCD (charge-coupled device) camera and recorded on line by means of accessorial computer system to evaluate the thermal shock resistance of tested samples while they were heated by a high heat flux of oxygen-acetylene flame to 1200° C in a time interval of 15~20s followed by water-quenched to ambient temperature. The temperature fields and relevant thermal stresses distribution through the thickness of disk samples were calculated by means of ANSYS finite element method. The numerical approach shows that the maximal tensile stress occur at the C-YSZ top coating at the center of disc samples at the start of rapid cooling by water-quenched, where small reticulated surface cracks were observed, which then propagated perpendicularly about 350µm deep to near the interface between the pure C-YSZ coating and the FGMs layer transition between the C-YSZ and the NiCoCrAlY coatings. These vertical cracks appeared to be arrested without any delamination after 200 thermal shock cycles.
HVOF Coatings of MoB/CoCr Against Erosion by Molten Al-Zn Alloy
Authors: Mizuno H. , Tawada S. , Aoki I. , Kitamura J. 
Published: September 2022

Abstract
MoB/CoCr with excellent durability against molten metal has been developed to be applied to aluminum die casting parts in automobile and to hot continuous dipping rolls in Zn and Al- Zn plating lines for steel industries. Our previous study has revealed that the MoB/CoCr coating prepared by high velocity oxy-fuel (HVOF) spraying has much higher resistance against attack of the molten Al-45wt%Zn alloys compared to conventional WC/12wt%Co coating from evaluation by laboratory scaled molten metal immersion test. However, performance with no damage is only limited when applying onto the substrate with smaller thermal expansion similar to the MoB/CoCr coatings. This paper describes the solution to prepare the MoB/CoCr coating without damage onto austenitic stainless steel of AISI316L with larger thermal expansion, whose material is commonly utilized for the hot continuous dipping rolls. It has been found that use of undercoat is effective to reduce the negative influence of large difference in thermal expansion between the MoB/CoCr coating and substrate of AISI316L. Optimized thickness of topcoat and undercoat and its combination showed intrinsic performance of low reactive MoB/CoCr without any mechanical damage such as crack and/or peeling.
Resistance of HVOF Nanostructured WC-12Co Coatings to Cavitation Erosion
Authors: Ding Z. , Zhang Y. , Zhao H. 
Published: September 2022

Abstract
Cavitation erosion is one of the major problems of hydraulic machinery and may cause the equipment to reduce power and then to stop working. Now with the study of nanomaterials, some special properties of nanostructured coatings are recognized and HVOF nanostructured WC-12Co coating may possess far more excellent potential to protect equipment from cavitation erosion than the conventional HVOF coatings. In the present paper nanostructured and conventional coatings were deposited by HVOF. Resistance of the coatings to cavitation erosion was studied by ultrasonic vibration cavitation equipment. Cavitation pits and craters were observed by SEM and cavitation mechanisms were explored. The results showed that nanostructured coating demonstrated more excellent performance in cavitation erosion and the erosion rate is approximately one third that of conventional one. The nanostructured existence and the increase in microhardness and toughness of the coating are important factors, which influence the resistance of coatings to cavitation erosion.
Liquid Precursors Plasma Spraying of TiO2 and Ce- Doped Ba(Zr0.2Ti0.8)O3 Coatings
Authors: García E. , Zhang Z.B. , Coyle T.W. , Hao S.E. , Mu S.L. 
Published: September 2022

Abstract
In this work was studied the suitability of Solution/Suspension Precursors Plasma Spray (SPPS) technique to produce titanium dioxide (TiO2) and cerium doped barium zirconium titanate (Ce doped Ba(Zr0.2Ti0.8)O3 or BZT) coatings. The precursors were sol-gel solutions typically employed to produce powders of those compositions. We report on the formation of porous TiO2 coatings on stainless steel substrates. The microstructures found this coatings are characterized by features typically found in solution precursor plasma spray processes; a combination of melted and unmelted deposits and small hollow spheres. Transmission electron microscopy revealed submicron/nanocrystalline features forming those deposits. Anatase was the main crystalline phase present in the TiO2 coatings. The rutile phase was also found in the coatings. The photocatalytic activity of the coatings was measured and compared with the results obtained for commercial anatase powders dispersed in liquid. Preliminary results obtained for Ce doped Ba(Zr0.2Ti0.8) O3 coatings deposited on mild steel substrates showed microstructures and crystalline phases suitable for dielectric applications.
Fabrication of Nano-TiO2 Coating for Dye-sensitized Solar Cell by Vacuum Cold Spraying at Room Temperature
Authors: Fan S.-Q. , Li C.-J , Yang G.-J. , Zhang L.-Z. , Gao J.-C. , Xi Y.-X. 
Published: September 2022

Abstract
Deposition of nanocrystalline TiO2 coatings at low temperatures is becoming more attractive due to the possibility for continuous roll production of coatings for assembly lines of dye-sensitized solar cell at a low cost. In this study, porous nano-TiO2 coatings were deposited by vacuum cold spraying at room temperature on a conducting glass substrate using commercial P25 nanocrystalline TiO2 powder. The microstructure of TiO2 coatings was characterized by field emission scanning electron microscopy and N2 adsorption test. A commercial dye (N719) was adsorbed on the surface of TiO2 particles within the coating to assemble a dye-sensitized solar cell. The cell performance was evaluated employing simulated solar light at an intensity of 100 mW/cm2. The results showed that TiO2 coatings were deposited by the agglomerates of nano-TiO2 powders. The BET test of the as-sprayed TiO2 coatings yielded a porosity of 49% and an average pore size of 17 nm. The assembled solar cell yielded a short-circuit current density of 7.3 mA/cm2 and an energy conversion efficiency of 2.4%. The test result indicates that vacuum cold spraying was a promising method to deposit nanocrystalline TiO2 coating at low temperature applied to the dye-sensitized solar cell.
LPPS Thin Film: A Hybrid Coating Technology Between Thermal Spray and PVD for Functional Thin Coatings and Large Area Applications
Authors: Refke A. , Gindrat M. , von Niessen K. , Damani R. 
Published: September 2022

Abstract
With the new development of the LPPS Thin-Film technology (LPPS-TF), which is a special modification of conventional LPPS using reduced chamber pressures below 10 mbar, a new window has been opened to deposit uniform and dense thin layers onto large areas in short coating times. This spray process will allow the access to new market areas and will be able to bridge the gap between conventional thin film (&lt; 1 - 10 µm) deposition using PVD/CVD processes and thick (&gt; 50 - 200 µm) thermally sprayed layers. This paper presents the status of the LPPS-Thin Film technology as a hybrid coating process between thermal spray and vapor deposition and gives an overview of potential applications for functional thin coatings and large area coverage.
Effect of In-Flight Particle Velocity on the Performance of APS YSZ Electrolyte
Authors: Zhang C. , Li C.-J. , Li C.-X. , Gao W. , Planche M. , Liao H. , Coddet C. 
Published: September 2022

Abstract
In this paper, the effect of velocity on the characteristics of atmospheric plasma sprayed yttria stabilized zirconia was investigated through adjusting auxiliary helium flow. The temperature and velocity of in-flight particles were measured with DPV2000 analyzer. The results showed that helium flow significantly influenced particle velocity and less distinctly influenced particle temperature. The microstructure of the coatings was characterized by scanning electron microscopy and X-ray diffraction analyzer. The ionic conductivity of the deposits through thickness direction was measured by a potentiostat/galvanostat based on three-electrode assembly approach in a temperature range of 500-1000 °C. The specific gas permeability was estimated. The results showed that the gas permeability was improved by increasing the in-flight particle velocity. However, the in-flight particle velocity has little effect on the ionic conductivity of specimens.
Fe-base Metal Glass Coating Produced by Gas Tunnel Type Plasma Spraying
Authors: Kobayashi A. , Yano S. , Kimura H. , Inoue A. 
Published: September 2022

Abstract
Metal glass has excellent functions such as high toughness and corrosion resistance. Therefore it is one of the most attractive materials, and many researchers have conducted various developmental research works. However, the metal glass material is expensive and the composite material is preferred for the industrial application. Thermal spraying method is one of potential candidates to produce those metal glass composites. The gas tunnel type plasma system, which has high energy density and efficiency, is useful for smart plasma processing to obtain high quality ceramic coatings such as alumina (Al2O3) and zirconia (ZrO2) coatings. In this study, the Fe-base metal glass coatings were produced by the gas tunnel type plasma spraying, and the microstructure and mechanical property were investigated. The Fe-base metal glass coatings of 100µm in thickness were formed densely with Vickers hardness of Hv =1000 at plasma current of 300A.
Mechanical Properties of Plasma-Sprayed Hydroxyapatite Coating after Post Heat Treatment: Effect of Residual Stress
Authors: Yang Y.C. , Chang E. 
Published: September 2022

Abstract
Through the measurement results of the residual strains of Hydroxyapatite coatings (HACs) and the values of Young’s moduli, the initial vacuum heating treatment (&lt;600°C) can release the compressive residual strain of HAC after plasma spraying, so enabling HACs to obtain the optimal bond strength at the heating temperature of 500~600°C. Nonetheless, the post-vacuum heating temperature higher than 600°C led to the deterioration of the bond strength of HA/Ti-substrate. With the increasing temperature, the increased compressive residual strain will weaken the interfacial adhesive force of coating to substrate, resulting in the lower bond strength with higher temperature. The results of this paper demonstrated that the proper temperature of post-vacuum heating treatment improved effectively the bonding strength between HAC and Ti-alloy substrate.
3D Visualization of Thermally Sprayed Microstructure
Authors: Ctibor P. , Hofmann P. , Chraska P. , Lechnerova R. , Benes V. 
Published: September 2022

Abstract
A short survey is given of various techniques of 3D visualization of voids and other structural defects that are inherently present in thermally spray structures. It is proven that the only condition for visualization is possibility to set up a distinguishable threshold based on the gray scale of the microscopical image of the structure. Segmented images are then further processed by commercial software for image analysis, animations and anaglyph files creation. Several softwares were applied and combined, such as Lucia, Voxblast, Amira and Voxler. The visualization technique was demonstrated on a ceramic plasma sprayed coating, where two kinds of voids – semi-globular pores and large interlamellar pores could be separated. Similarly, this visualization technique can be used to distinguish between pores and oxide particles in case of metallic coatings. The visualization is done in a real Cartesian space without any transformation. The results can be useful mainly for: a) teaching to get a better insight into the microstructure of thermally sprayed coatings, b) research, where in combination with mathematical quantification the visualized structure can show important distinctions between coatings sprayed by different techniques and with variety of process parameters.
Evaluation of Strain Field Around Impacted Particles by Applying Electron Moiré Method
Authors: Watanabe M. , Kishimoto S. , Shinoda K. , Kuroda S. 
Published: September 2022

Abstract
Recently, the thermal spray community has focused considerable attention on Cold Spray and Warm Spray techniques, in which the temperatures of sprayed particles are kept under the melting points and adhesion occurs based on the impact phenomenon between a solid particle and a substrate. The mechanisms of adhesion are still unclear but the degree of the mechanical deformation at the interface is considered to be one key factor. However, it is very difficult to directly measure the strain at the interface. Instead, in this work, the strain fields on a substrate around an impacted particle were measured by applying Electron Moiré method, and corresponded to the spray conditions by a warm spray deposition.
Impingement Resistance of HVAF WC-based Coatings
Authors: Deng C. , Zhou K. , Liu M. , Song J. , Wu C. 
Published: September 2022

Abstract
HVO/AF (High-Velocity-Oxygen/Air-Fuel) WC-17Co and WC-10Co4Cr coatings exhibit great potential in the replacement of electrolytic hard chrome (EHC) coating, and comprehensive properties of such coatings should be not worse than those of electrolytic hard chrome coating. The impingement-resistance of HVAF coatings sprayed on 300M ultra-high strength steel was studied in this paper. As an important property index, the fracture toughness of HVAF WC coatings was measured using micro-indentation method at the load of 9.8, 19.6, 24.5, 29.4 and 49.0N respectively. The cracks resulted from stress concentration in the micro-indentation were analyzed. The impingement-resistance for two HVAF WC coatings and EHC was evaluated according to the ASTM D3170 standard, and steel ball dropping experimentation was performed at the height of 0.61, 1.52, 1.83, 2.36 and 2.59m respectively. The cracks caused by both impingements were analyzed using SEM and optical microscopy in comparison with cracks in micro-indentation test.
Investigation of the Corrosion Behavior of HVOF-Sprayed Carbide Cermet Coatings in Molten Al-Zn-Si Alloy Bath
Authors: Tan X.H. , Jiang Z.H. , Zhang Y.G. , Sun J.S. 
Published: September 2022

Abstract
In the continuous hot-dip galvanization process, the corrosion and chemical stability of the sink roll in the galvanizing bath are important issues that affect quality and productivity. In order to protect the sink roll, carbide cermet and/or ceramic coatings were deposited on the surface of the sink roll. The WC-, Cr3C2- cermet coatings were deposited by high velocity oxygen fuel (HVOF) spray, respectively. The coating samples were immersed in molten Zn-alloy containing 50wt.% aluminum at 833K for 24 hr and 144 hr, respectively. The inter-diffusion and inter-reaction of Zn, Al and elements in the coating and corrosion behavior of these coatings were investigated by XRD, SEM and EPMA, etc. The corrosion mechanisms of the carbide cermet coatings and ceramic coatings in molten High Al-Zn-alloy were proposed.
Erosion Properties of Plasma Sprayed Ceramic Coatings Against Process Plasma in Semiconductor Production Equipment
Authors: Kitamura J. , Ibe H. , Mizuno H. , Aoki I. 
Published: September 2022

Abstract
Erosion properties of high purity alumina (Al2O3) and yttria (Y2O3) coatings prepared by plasma spraying have been investigated against process plasma in semiconductor and liquid-crystal-display (LCD) production equipments for dry etching. Studies on plasma power dependency have revealed that yttria coatings have showed higher anti-plasma erosion resistance than alumina coating as well as sintered alumina bulk at every condition. Although yttria coatings are inferior to sintered yttria bulk, the difference of the resistance becomes smaller with increasing plasma power. This result positively promotes the application of the yttria spray coating because of increasing plasma power in actual process. Erosion properties of the coatings against Ar/CF4/O2 plasma, whose composition is increasingly being used in commercial process, are also investigated where physical etching effect becomes stronger than the typical CF4/O2 case. It has been found that order of durability (yttria bulk &gt; yttria coatings &gt; alumina bulk &gt; alumina coating) is independent of the gas species used in this study. The mechanism of the plasma erosion is discussed through micro-structural analysis of the eroded surfaces.
Microstructure and Properties of Silicon Coating Prepared by Air Plasma Spraying
Authors: Niu Y.R. , Liu X.Y. , Zhou X.M. , Ding C.X. 
Published: September 2022

Abstract
In the present work, silicon coating was deposited using air plasma spraying technology. The temperature and velocity of particles in the plasma spraying were measured. The phase composition and microstructure of the coating was studied. And some mechanical and thermal properties of the coating were evaluated.
Influence of Particle Size on Microstructure and Properties of Al2O3 Coatings Deposited by Plasma Spraying
Authors: Yin Z.J. , Tao S.Y. , Zhou X.M. , Ding C.X. 
Published: September 2022

Abstract
In the present study, Al2O3 coatings were deposited by plasma spraying using feedstock of different particle sizes. The effects of particle size on their velocity and temperature in the plasma jet, the microstructure and properties of the coatings were investigated. The results revealed that in view of the smaller inertia effects and lower heat capacity, the smaller particles can be easily accelerated and heated, and have higher in-flight velocity and temperature, which contributed to produce a denser coating with lower porosity and higher mechanical properties. It was also found that the coating deposited using the finest starting powder has the lowest thermal diffusivity. This may be reasonably correlated with the microstructural characteristics. In addition, the coating manufactured using the intermediate feedstock in terms of particle size (D50 of 19.3µm) exhibited the highest wear resistance.
Properties of Copper Coatings Deposited by Multi-function Micro-plasma Spraying
Authors: Liu G. , Wang L.Y. , Wang H.G. , Hua S.C. 
Published: September 2022

Abstract
In this paper, copper coatings were deposited on a metallic substrate by means of multi-function micro-plasma spraying under different processing parameters. The microstructure and phase structure of copper coatings were investigated using a scanning electron microscope and X-ray diffraction, bonding strength were tested by an electron tensile tester, droplet impinging and flattening on a flat substrate surface and the residual stress after solidification were studied numerically. The experimental results show that the density of copper coatings was improved with increasing plasma power and operating gas flow, and this copper coating possessed high adhesion strength and low residual stress, still without obvious oxidation. This spraying system extends the application field of tradition plasma spray. Through changing the processing parameters, materials with different melting points, even as low as copper can be produced.
Effects of Laser Irradiation on Plasma Sprayed AI2O3 Coatings
Authors: Kobayashi Y. , Ohmura E. , Ueki S. 
Published: September 2022

Abstract
In order to clarify the effects of two kinds of laser irradiation on plasma sprayed alumina coatings, microstructure, crystallization and mechanical properties of the spacemen were examined and heat conduction in the laser irradiation processes were analyzed by a finite element method. One is CW CO2 laser irradiation of low power density, and the other is pulse excimer laser irradiation of high intensity but low energy density. Al2O3 coatings were irradiated by CO2 laser with low intensity, fine structure formation composed of α- Al2O3 was confirmed and the surface roughness was improved although the hardness decreased a little. The modified layer was corresponding to the area that was heated above 1000 to 1100°C in the calculated maximum temperature distribution. It was also confirmed that the excimer laser pulse has a potential to improve the properties of surface layer to a depth of several micrometers.