bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suspension Plasma Spray YSZ Feedstocks and Delivery System for Improved Spray Distance and Cost Effective Throughput
Authors: Callen B. W. , Roccio-Heller R. , Liu J. , Sabouni O. 
Published: November 2022

Abstract
Yttria-Stabilized Zirconia (YSZ) suspensions are currently popular in developing strain resistant columnar structured thermal barrier coatings by Suspension Plasma Spray (SPS) as a less costly alternative to conventional EB-PVD. Coatings produced by SPS have a disadvantage of reduced usable spray distance, compared to conventional APS, due to quenching of the plasma by the suspension liquids, which are most commonly alcohol-based. The reduced spray distance can interfere with the coating process for substrates with complex geometries such as turbine blades. This paper shows how spray distance can be increased by using larger suspension particle sizes that are not normally considered for SPS. Such large particle suspensions are shown capable of producing columnar or segmented YSZ coating microstructures that are similar to those produced by submicron particle suspensions, but at longer and more practical spray distances. Another limitation to SPS process technology is the delivery system of feedstock from the point of manufacture to the SPS feed hopper. Current commercial ready-to-use suspensions have limitations involving cost, transportation and storage that effect both the producers and the end-users. An alternative suspension delivery system may be applied to SPS feedstock materials, including current sub-micron and the coarser particle size cuts described herein. Discussed is a pre-formulated dry feedstock that is constituted into fresh suspension by the end-user with locally sourced liquid media and appropriate high-speed mixing equipment. This alternative delivery system for suspensions provides lower cost materials and process flexibility that is particularly suited to commercial scale SPS coating facilities.
The Influence of the Coating Deposition Process on the Interdiffusion Behavior Between Nickel-Based Superalloys and MCrAlY Bond Coats
Authors: Elsaß M. , Frommherz M. , Oechsner M. 
Published: November 2022

Abstract
In this work, interdiffusion between different nickel-based superalloys and two MCrAlY bond coats, containing different chemical compositions, is investigated. To determine the influence of the coating deposition process, the MCrAlY bond coats were applied using two different spraying processes, high velocity oxygen fuel spraying (HVOF) and low-pressure plasma spraying (LPPS). Of primary interest is the evolution of Kirkendall porosity, which can form at the interface of substrate and bond coat and depends largely on the chemical compositions of the coating and substrate. Experimental evidence suggested also a dependence on the coating deposition process. Formation of porosity at the interface causes a degradation of the bonding strength between substrate and coating, with functional breakdown of the coating system as a worst result. After coating deposition, the samples were annealed at 1050 °C for varying test periods up to 2000 hours. Microstructural and compositional analyses were performed to determine and to evaluate the Kirkendall porosity. The results reveal a strong influence of both the spraying process and the chemical composition. The amount of Kirkendall porosity formed, as well as the location of appearance and the shape, is largely influenced by the coating deposition process. In general, samples with bond coats applied by means of HVOF show accelerated element diffusion. It is hypothesized that recrystallization of the substrate material, as a consequence of the surface treatment prior to coating deposition, is the main root cause for these observations.
Evolution of Residual Stresses in PS-PVD TBCs with Thermal Cycling
Authors: Tao S. , Yang J. , Zhao H. , Ni J. , Zhong X. , Zhuang Y. 
Published: November 2022

Abstract
Cr3+ Photoluminescence piezo-spectroscopy (CPLPS) has been developed as a non-destructive inspection technique for the measurement of residual stresses within the thermally grown oxide (TGO) in thermal barrier coatings (TBCs). In this study, plasma spray - physical vapor deposition (PS-PVD) process was used to deposit yttria stabilized zirconia (YSZ) topcoat with quasi-columnar structures. Evolution of the microstructures and residual stress distribution in such kind structured TBCs before and after thermal cycle test on burner rigs were investigated. The accumulated tensile stress in the as-sprayed ceramic topcoat changed to compressive state after 100 cycles, and then gradually increased. In addition, the mapping compressive stresses in the TGO measured through the ceramic topcoat surface decreased rapidly firstly and then essentially maintain at a relatively stable value with further testing. Moreover, the pre-oxidation of the bondcoat could significantly affect the stress distribution in the TGO, in contrast, no obviously influence on the stresses in the YSZ topcoat.
Wetting Properties of Ceramic Reinforced Metal Matrix Composites on Varied Roughness Profiles
Authors: Vijay S. , Roy B. , Markocsan N , Lyphout C. 
Published: November 2022

Abstract
Superhydrophobic surfaces are of great importance in many industrial applications, especially where components are exposed to wet environments and low temperatures. Texturing of surfaces to reach superhydrophobicity can be achieved by thermal spraying technology, which is an attractive coating method as it is cheap, flexible and can employ a large range of feedstock materials. In this study, ceramic reinforced metal matrix composite (WC-CoCr) powders were sprayed using High Velocity Air Fuel method. They were varied based on their powder parameters such as carbide grain size, binder grain size and powder strength. The purpose was to investigate their hydrophobic characteristics and how these are influenced by different roughness profiles. The wetting properties such as contact angle and contact angle hysteresis were first investigated for the as-sprayed coatings. The roughness properties and Hausdorff Dimension were then related to the wetting properties. Aside from as-sprayed coatings, the effect of roughness and inherent wetting characteristics were studied by investigating the coating surface after grit blasting and polishing. Results show that powder parameters can lead to designing surfaces with higher surface roughnesses and thus having higher contact angles. It was also shown that surface composition of cermets has an impact on wettability, with the binder accounting for wetting characteristics and carbides accounting for roughness.
Detonation Spraying of Refractory Metals
Authors: Ulianitsky V. , Batraev I. , Shtertser A. , Dudina D. , Bulina N. , Smurov I. 
Published: November 2022

Abstract
Due to high melting temperatures and excellent corrosion resistance of refractory metals, they are used for manufacturing parts working under extreme conditions. The formation of refractory metal coatings by thermal spraying is associated with two major challenges: 1) particles of materials having high melting temperatures should be heated to reach a semi-molten or a molten state; 2) oxidation of the metals should be prevented. In this work, the CCDS2000 detonation spray system was used for obtaining molybdenum and tantalum coatings. The coatings were deposited on steel substrates at O2/C2H2=1.1 and stand-off distances of 20 mm and 100 mm. The calculation of the particle temperatures and velocities were carried out to find the optimal spraying modes for Mo and Ta powders. No oxide phases were found in the coatings obtained by spraying of the Mo powder. In the Ta-based coatings, Ta2O5 was found as a second phase. The hardness of the Mo coatings sprayed at 20 mm and 100 mm was 500 HV300 and 625 HV300, respectively. The porosity of the Mo coatings was less than 0.5% for both stand-off distances. The hardness of the Ta-based coatings sprayed at 20 mm and 100 mm was 800 HV300 and 1000 HV300, respectively. The porosity of these coatings was less than 1% for both stand-off distances. The bond strength of the Mo coatings determined by the pin test method was 92 and 126 MPa and that of the Ta-based coatings was 43 and 77 MPa, for coatings deposited at 20 and 100 mm, respectively.
Enhanced Corrosion Resistance of Magnesium Alloys by Transplantation of Thermally Sprayed Coatings
Authors: Rodriguez Diaz M. , Knödler P. , Otten M. , Möhwald K. , Freiburg D. , Kersting P. , Biermann D. 
Published: November 2022

Abstract
Despite their excellent specific mechanical properties magnesium-based alloys are not widely used in the industry due to their high affinity to oxygen. Given the need for lightweight design, there are increasing efforts to replace high density materials by magnesium. One way to cope with the high oxygen affinity of magnesium is the use of thermally sprayed anti-corrosion coatings. However, conventional thermal coating processes have various process-related limitations. A case in point is coating of complex geometries and internal coatings with small diameters that often cannot be realized by conventional processes. Due to the changed process order some of the limitations of conventional coating methods can be resolved by the transplantation of thermally sprayed coatings. This method is a composite casting process for the coating of die cast components, where the thermally sprayed coating is applied to the corresponding area of the mold prior to the casting process. The aim of this study is to compare the effectiveness of transplanted thermally sprayed coatings with corrosion protection properties to conventional coatings deposited by thermal spraying and to discuss the ramifications with respect to industrial applications.
Comparison of Wear Performance of Thermal Sprayed Cermet (WC-Co) Coatings from Suspension and Feedstock Powders
Authors: Ali O. , Ahmed R. , Alawadhi H. , Shameer M. , Faisal N. , Al-Anazi N. , Goosen M. 
Published: November 2022

Abstract
WC-Co coatings were deposited using conventional High Velocity Oxy-Fuel Jet-Kote (HVOF-JK) and Suspension HVOF (S-HVOF) methods. Microstructural and mechanical properties along with the wear resistance of coatings were investigated. Reciprocating sliding wear tests were conducted against sintered Si3N4 counter-body with a normal load of 25N and total sliding distance of 500m following ASTM G133-2 standard. Coatings were characterised by Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and nano-Indentation techniques. HVOF-JK coating showed good retention of WC whereas S-HVOF coating showed the presence of W, W2C and amorphous/nanocrystalline phases. Nano-indentation of HVOF-JK and S-HVOF showed that the relative hardness of the HVOF-JK coating was higher but their elastic modulus was lower. The lower total wear rate was exhibited by the HVOF-JK coating. This difference in wear performance is attributed to the difference in hardness of the coatings and decarburisation of WC particles.
Effect of Spraying Parameters on the Bonding Strength of Detonation Sprayed WC-Ni Coatings
Authors: Baldaev L. , Khamitsev B. , Baldaev S. , Ahmetgareeva A. , Prokofjev M. 
Published: November 2022

Abstract
Well-known detonation thermal spraying is considered to be a good method for the preparation of WC-based coating with high adhesion. The depositing parameters, especially the oxygen-fuel ratio and spot frequency, have been observed to influence the properties of the coating. The influence of the main parameters of the detonation spraying of tungsten carbide based coatings and their mechanical properties have been investigated. Two main tasks for the development of a carbide-containing material application technology have been determined. The relationship between the phase composition of WC-based coatings and their strength, hardness and bond strength to the substrate has been identified. The technique of coating in the reductive mode has been proposed. High oxygen-fuel ratio and spot frequency decreased the decomposition of the WC-phase, which makes the WC-Ni particles harder and as a result more easily embedded in the substrate, i.e. the coating which is beneficial to enhance bonding strength.
Solution Heat Treatment of Gas Atomized Aluminium Alloy (7075) Powders: Microstructural Changes and Resultant Mechanical Properties
Authors: Sabard A. , de Villiers Lovelock H. , McNutt P. , Harvey D. , Hussain T. 
Published: November 2022

Abstract
Cold gas dynamic spray has significant potential for load-bearing repairs of high-value metallic components, as it is capable of producing pore and oxide-free deposits of significant thickness and with good levels of adhesion and mechanical strength. However, recently published research has shown that the rapid solidification experienced by gas atomised powders during manufacture can lead to a non-equilibrium powder microstructure, including clusters of dislocations as well as significant localised segregation of alloying elements within each particle. This paper reports on an investigation into the solution heat treatment of a precipitation hardenable aluminium alloy powder. The objective was to create a consistent and homogeneous powder phase composition and microstructure before cold spraying, with the expectation that this would also result in a more favorable heat treatment response of the cold spray deposits. Aluminium alloy 7075 gas atomized powders were solution heat treated at 450 °C for 5 hours in a sealed glass vial under vacuum and quenched in water. The powder particle microstructures were investigated using scanning electron microscopy with electron back scatter diffraction (SEM/BSE) and optical microscopy. The dendritic microstructure and solute segregation in the gas atomized powders was altered, with the heat-treated powder particles exhibiting a homogeneous distribution of solute atoms. The influence on the mechanical properties of the powder particles was studied using micro-indentation. The heat-treated powders exhibited a hardness decrease of nearly 25% compared to the as-received powders. This paper relates the behavior and the deformation of both as-received and heat-treated powders during spraying (single particle impacts), comparing the measured hardness with the deformation effect and the material jetting occurring upon impact.
Effect of Powder Granularity in the Pack on Microstructure and Anti-Oxidation Properties of SiC Coatings for C/SiC Composites
Authors: Jia F. , Ji X. , Peng H. , Shen J. , Zhang D. , Yu Y. 
Published: November 2022

Abstract
SiC coatings were prepared with pack powder in different particle sizes in a vacuum atmosphere by pack cementation technique to protect the C/SiC composites substrate from oxidation. The phase and microstructure of the coatings were investigated by XRD, SEM analyses. The relationship between powder granularity in the pack and microstructure of SiC coatings was studied. Cyclic oxidation test at 1573K in air atmosphere was performed and the effect of powder particle size in the pack on high-temperature oxidation resistance of SiC coatings was discussed in detail. It is observed that with powder granularity in the pack increasing thickness and density of SiC coatings increases, corresponding oxidation resistance of the coating is improved. Possible mechanisms related to oxidation were preliminarily discussed.
An Alternative Die Coating Method on Low Pressure Die Casting Mould by Thermal Spraying
Authors: Altincu E. , Ustel F. , Burak Çe Ö. 
Published: November 2022

Abstract
In the world, automobile rim production is carried out in a repeatable quality with low pressure die casting process. Traditional die coatings used to separate molds on casting mold surfaces cause significant losses in production due to their weak strength. The applicability of an alternative mold coating application with thermal sprayings has been examined in this study. MgO-ZrO2 based ceramic thermal barrier coatings are deposited on the mold surfaces by flexicord spray method.
Thermal Gradient Cyclic Lifetime of La2Zr2O7/YSZ Double Ceramic Layer Thermal Barrier Coatings with Equivalent Thermal Insulation Performance
Authors: Cheng B. , Yang G.-J. , Zhang Q. , Yang N. , Zhang M. , Zhang Y. , Li C.-X. , Li C.-J. 
Published: November 2022

Abstract
Thermal insulation performance is a measurement of the thermal protection offered by the thermal barrier coatings (TBCs) to the substrate, therefore, it is essentially important to compare different double ceramic layer (DCL) TBCs on the premise of the same thermal resistance. In this study, a series of LZO/YSZ DCL-TBCs, with the equivalent thermal insulation to 500 µm thick YSZ TBCs, were prepared, and their lifetimes were evaluated by thermal gradient cyclic test at the top coat surface temperature of 1300°C. Result show that, the lifetime of DCL-TBCs was more than doubled compared to 500 µm thick YSZ TBCs, when 100µm thick YSZ coating was substituted by LZO coating. In addition, the lifetime of DCL-TBCs decreased with the increase of LZO substitutional ratio. X-ray diffraction analysis revealed that LZO maintains the pyrochlore structure after thermal cyclic test. Microstructure examination demonstrated that, with the increase of LZO substitutional ratio, the delamination position transferred from near top/bond coating interface to near LZO/YSZ interface and finally to the inside of LZO coating. Therefore, this study would shed light to further coating structure optimization towards the next generation advanced DCL-TBCs.
Morphology and Durability of Sm2Zr2O7+8YSZ TBC Systems During Oxidation Test at Temperature 1100°C
Authors: Jucha S. , Moskal G. , Mikuśkiewicz M. 
Published: November 2022

Abstract
The zirconates of rare earth elements, such as Sm2Zr2O7 ceramic, can be an alternative material, for commercially and widely used for insulation layers in thermal barrier coatings (TBC) systems, zirconia modified by yttria (8YSZ). Presented article described the internal morphology of composite TBC coatings of Sm2Zr2O7+8YSZ type with different ratio of both used to coatings deposition powders (25/75, 50/50 and 75/25) as well as the TBC of double ceramic layer (DCL) type with a 8YSZ internal layer and the outer layer of Sm2Zr2O7 type. The main subject of presented investigations is related with the oxidation resistance of TBC systems during static oxidation test at temperature 1100°C. In this case, the special emphasis was on characterization of thermally grown oxides (TGO) zone thickness where the most important phenomena related with overall live-time of TBC system usually take place.
The Influence of Post Treatment Presence on High Temperature Corrosion Resistance of YSZ Thermal Barrier Coatings
Authors: Akhmetgareeva A. , Baldaev S. , Mazilin I. , Baldaev L. , Il’inkova T. 
Published: November 2022

Abstract
Well known that high temperature corrosion resistance of thermal barrier coatings (TBC) may depend not only on chemical composition, thickness, the rate of formation of TGO layer, but also on the presence of post treatment. In this work we studied the influence of presence of post treatment on properties of TBC particularly on high temperature corrosion. TBC system were sprayed on Ni-based substrate and consists of HVOF NiCo-based bond coat (BC) and APS yttria-stabilized zirconia (YSZ) top coat. Thermal cycling test in the presence of corrosive environment was used to determine effect of post treatment presence. Before and after Thermal cycling test cross-section of specimens were studied by SEM and EDX analyzes. Preliminary results demonstrated that high temperature corrosion resistance of TBC with APS-top layer and HVOF-bond layer can be improved by applying post treatment.
Production Advantages Using Laser Cladding as an Additive Manufacturing Method
Authors: Bihlet U. D. , Honoré M. , Nielsen P. T. 
Published: November 2022

Abstract
The potential of additive manufacturing has reached a point where the techniques are considered highly relevant for production purposes. In general, the manufacturing industry greets the new approach with enthusiasm, as it offers innovative designs and potentially reduced production costs. However, questions arise concerning the durability of additively manufactured components. This paper describes industrial trials with laser cladding and precipitation hardening heat treatment of thin-walled structures with the 17-4 PH stainless steel alloy. Due to the great relevance of the AM production methods for the aviation industry, the mechanical strength of the alloy given by the MMPDS document is used as a baseline. In order to improve the properties of the produced specimens, hot isostatic pressing was applied. The results show that a post processing treatment consisting of a HIP cycle and a conventional precipitation hardening, vastly improves the mechanical strength and elongation values of printed specimens, causing them to exceed the specified values.
Comparison of Microstructure and Tribological Behavior of WC Reinforced Maraging Steel 300 Composites Prepared by Cold Spraying and Selective Laser Melting
Authors: Yan X. C. , Huang C. J. , Bolot R. , Lucas D. , Liao H. L. , Huang R. Z. , Ma W. Y. , Liu M. 
Published: November 2022

Abstract
Tungsten carbide (WC) is a well-known material used to increase the wear resistance of iron-based composite materials that exhibit a favorable wettability with iron alloy particles. In this work, two different additive manufacturing technologies, i.e., cold-spray additive-manufacturing (CSAM) and selective laser melting (SLM), were used to fabricate WC/maraging steel 300 (WC/MS300) composites. An investigation comparing the microstructure and tribological behaviors of the composites was carried out. In addition, the evolution of the reinforcement phase during these two processes was characterized by SEM and EDS methods.
The Influence of Process Parameters on Structure and Functional Properties of Laser Clad WC-NiCrBSi Coating
Authors: Vostřák M. , Houdková Š. , Česánek Z. 
Published: November 2022

Abstract
In this study, the influence of main laser cladding parameters on the final microstructure of cladded WC-NiCrBSi coating is discussed. As the used powder is the blend of 60% tungsten carbide spherical particles and 40 % NiCrBSi matrix, the carbides’ morphology and distribution in the final coating are dependent on laser cladding parameters. The variability of coating’s microstructure strongly influenced their wear resistance. In the paper, the influence of laser processing parameters on final coating microstructure is studied. The functional properties of cladded coatings are evaluated by dry sand rubber wheel test ASTM G-65. The wear resistance of the coating is dependent on the amount of undissolved carbides particle in the coating.
Transient Coating Buildup and Thermal Analysis of Cold Spray Process by Finite Element Modelling
Authors: Chen C. , Xie Y. , Verdy C. , Liao H. , Deng S. , Ren Z. 
Published: November 2022

Abstract
Since cold spray is widely considered as an additive manufacturing and damage repair technology, it is crucial to understand the coating build-up process and the temperature evolution. In this work, a 3D numerical model was developed to simulate the transient coating build-up process as well as the heat transfer in cold spray. By coupling the heat transfer with the ALE (Arbitrary Lagrangian–Eulerian) moving mesh and coating thickness model, this 3D model is able to investigate the temperature evolution of a coating which simultaneously grows according to the nozzle trajectory. The nozzle trajectory that represents the heat source and mass flux of particle impact is generated and simulated in the offline programming software RobotStudio. By assigning the results of coating thickness distribution, the simultaneous build-up of coating computational domain is achieved by ALE moving mesh method. The validation of the FEA (finite element analysis) model was carried out by measuring the coating surface temperature via an infrared imaging camera. With the proposed model, it is able to study the actual coating build-up process as well as the heat transfer phenomena, which may provide more insights for the application in additive manufacturing and damage repair.