bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlating the Spray Pattern to the Coating Architecture: Exploring the Dominant Mechanisms and Process Parameters
Authors: Montavon G. , Berndt C.C. , Trifa F.I. , Guessasma S. 
Published: August 2022

Abstract
The plasma spray process is unique because the coating properties depend indirectly on the processing parameters. Therefore, the in-service properties derive mostly from the coating architecture. The coating architecture is related to the intrinsic lamellae formation mechanism; which is related to the impinging particle characteristics that are linked to the power and feedstock injection. The coating architecture is also related to the extrinsic spray pattern formation mechanism; i.e., the kinematics and geometric spray parameters such as spray velocity, spray angle, and stand off distance. Understanding relationships between coating architecture and its properties requires consideration of the whole coating formation process. Ultimately, this permits selection of process parameters that demonstrate enhanced spray efficiencies and manufacturing capability. Included in this study are the pore network architecture and residual stress level because they play important roles in coating cohesion from which derive most of the in-service properties. Coating manufacturing mechanisms, from the spray pattern to an actual coating formed by several successive patterns, are investigated in this paper. The case of atmospheric plasma sprayed Al2O3-TiO2 (13% by wt.) is considered. Data are statistically assessed by implementing Gaussian and Weibull analyses. The critical role of pores which develop within the spray pattern and between successive patterns is examined in detail. There is contamination between layers and the intrinsic roughness of the coating is altered during the spray process. In summary, within this work, it is intended to define the intrinsic and extrinsic operational variables that contribute to the coating architecture and, thereby, suggest technology that can be implemented to improve coating quality and deposition efficiency.
Plasma Spraying of a Novel Material with Amorphous and Nanocrystalline Microstructure
Authors: Chraska T. , Neufuss K. , Dubský J. , Nohava J. , Oberste-Berghaus J. 
Published: August 2022

Abstract
A novel material has been used for plasma spraying by WSP. The material is composed of three main phases, namely corundum (aluminum oxide), baddeleyite (zirconium oxide), and glassy phase (silicon oxide). The material is a refractory and exhibits very high hardness, extremely high abrasion resistance, and chemical resistance. Conventionally, the material is fabricated by melt casting and machining. Cast tiles of the material were ground and sieved to obtain the right powder cut size for plasma spraying by water stabilized plasma torch (WSP). Both dense coatings and free standing parts were achieved with the new material, which sprays very well with WSP. Spraying parameters were varied and molten particles were monitored in flight by DPV 2000. The coatings exhibit very low porosity and high hardness. The as-sprayed material is mostly amorphous with some nanocrystalline grains of aluminum and zirconium oxide present. The phase composition of the as-sprayed material is thus different from that of the feedstock material, which is mostly crystalline with a small fraction of amorphous silica glass. The microstructure of the newly sprayed material was studied by electron microscopy (SEM, TEM) and is very complex. Upon annealing, the as-sprayed material crystallizes around 950ºC. This result and other thermal properties were measured by TMA and DTA. The ease of plasma spraying and the coating properties make this material a suitable candidate for many industrial applications.
Development of Metal Based Thermal Barrier Coatings (MBTBCs) for Low Heat Rejection Diesel Engines
Authors: Shin D. , Gitzhofer F. , Moreau C. 
Published: August 2022

Abstract
In this work, metal-based thermal barrier coatings (MBTBCs) for use in low heat rejection diesel engines have been produced, using high frequency induction plasma spraying (IPS) of iron-based nanostructured alloy powders. Important advances have been made over recent years to the development of ceramic-based thermal barrier coatings (TBCs) for diesel engines, but they are not yet applied in mass production situations. Besides the important economic considerations, the reliability of ceramic TBCs is also an issue, being associated with the difficulty of predicting their “in-service” lifetime. Through engineering of the nano/amorphous structure of MBTBCs, their thermal conductivity can be made as low as those of ceramic-based TBCs, with reduced mean free paths of the electrons/phonons scattering. In this work, nano/amorphous structured coatings were deposited by IPS using the following spray parameters: spraying distance (200mm), plasma gas composition (Ar/N2-85/15, by volume %), IPS torch power (25kW), and powder feed-rate (16g/min.). The structure and properties of the deposited layers were characterized through SEM (Scanning Electron Microscopy) observations. The thermal diffusivity (α) properties of the MBTBCs were measured using a laser flash method. Density (ρ) and specific heat (Cρ) of the MBTBCs were also measured, and their thermal conductivity (k) calculated (k =αρCp). The thermal conductivity of MBTBCs, with 7.5% total porosity, was found to be 1.22 W/m/K. The heat treatment study showed that phase transformation started at 650oC, and grain size growth from nano- to micron- scales occurred at around 1000°C under static exposure conditions. Thermal expansion coefficient (TEC) of MBTBCs was 15E-6 /K, which is close to the TEC of cast iron and thus, closer to the TEC values of aluminium alloys than are conventional TBCs. Fracture toughness of MBTBCs has also been assessed by use of Vickers hardness tests, with a 100 g load for 15 s, and the results show that there are no measurable crack developments around “indented” areas on all samples of MBTBCs tested.
Thermo Mechanical Behaviour of Nano Structured Plasma Sprayed Thermal Barrier Coatings
Authors: Soltani R. , Coyle T.W. , Mostaghimi J. 
Published: August 2022

Abstract
Thermally sprayed ceramic coatings deposited from nanostructured feedstock powder have often shown improved mechanical properties comparing to coatings produced from convention feedstock. Bimodal structured ceramic deposits have been reported to demonstrate better properties such as wear resistance, adhesion strength and toughness. For thermal barrier coatings, high temperature performance is a key point especially creep/sintering. In this study creep/sintering rate of plasma sprayed, bimodal structured, yttria stabilized zirconia coatings were investigated. The creep behaviour was investigated using free standing thick (3 mm) coating layers loaded in the four point bending setup at two temperatures : 800 and 1000 ºC in air. Under the same test conditions the creep results for nanostructured coatings and conventional plasma spray coatings have been compared together and the former one in both temperatures showed a lower creep rate.
Corrosion Properties of X-HVOF Corrosion Protective Coatings
Authors: Wank A. , Wielage B. , Jansen F. , Wieczorek D. , Höhle H.-M. 
Published: August 2022

Abstract
Titanium grade 2 as well as steel 446 and 316L powders are applied for production of X-HVOF coatings on mild steel substrates. Deposition efficiency is determined by process parameters. Microstructural investigations are carried out by means of optical microscopy, SEM and XRD. In addition comparisons of oxygen and nitrogen content in titanium coatings and powder feedstock are drawn. Corrosion protection capability of produced coatings is studied by current density-potential measurements and by salt fog tests. Depending on the process parameters increase of oxygen and nitrogen content can be restricted to factor of 2 compared to the powder feedstock. Coatings showing nearly theoretical density in metallographical inspections are possible. In direct comparison to wrought titanium grade 2 material the corrosion behavior of the titanium coatings is very promising. Keeping in mind that coatings have been produced under atmospheric conditions the observed increase of the corrosion current density by factor four is regarded an excellent result. During the corrosion tests no damage, neither to the surface nor the substrate - indicated by rust precipitates on the specimen surface, is observed. So penetration of corrosive medium to the substrate is securely avoided.
The Quality Control in Plasma Spraying Ceramic Coating on Large Area Substrate
Authors: Liu M. , Zhu H. , Li Y. , Zhou K. 
Published: August 2022

Abstract
In this paper, the quality control in plasma spraying of chromium oxide ceramic coating on large area substrate is studied. This paper consists of three parts. Firstly, basic technical parameters are studied, for example, electric current, voltage, gas, powder, and spray distance. Secondly, the effect of dust from the spraying process on the coating quality is studied. Finally, the character of chromium oxide coating is researched. The results show that the dust from the spraying process greatly affects the coating quality. The effect of the following variables is examined: spray parameters, the powder size and distribution, and the substrate size. We have designed a set equipment to control the coating quality and the result was excellent. Now the equipment has been used in the production of anilox rollers and the patent has been applied. Meanwhile, we have devised a standard to determine the quality when spraying ceramic coating on large area substrate. The method has proved useful and efficient. Abstract only; no full-text paper available.
Reinforced Lightweight Composite Materials
Authors: Tillmann W. , Vogli E. , Weidenmann K. , Fleck K. 
Published: August 2022

Abstract
Nowadays the use of light weight materials increases rapidly. Owing to growing requirements regarding material properties and corresponding production costs new material designs and novel production concepts are needed. The low density of aluminium and its alloys is accompanied by lower Young’s modules and lower strengths compared to steel. These disadvantages regarding to stiffness and strength can be overcome by using a composite material consisting of aluminium and embedded endless reinforcing elements. In this work a novel technology based on the thermal spraying process to manufacture endless reinforcing elements for extrusion molding of Al-profiles will be discussed. A specific handling system for arc-spraying Al-alloys onto steel wires has been developed. The influence of the coatings materials and coating parameters on the subsequent extrusion moulding process has been studied.
Microstructures and Abrasion Resistances of Laser Cladded MMC-Coatings
Authors: Nurminen J. , Näkki J. , Vuoristo P. 
Published: August 2022

Abstract
Laser cladding is a novel way to produce metal matrix composites for need of abrasion resistant coatings. There are, however, few comparative studies concerning the choice of reinforcing material and the metallic matrix material. In this study, MMC’s were formed from vanadium-, tungsten- and titanium carbides mixed with tool steel M2, Stellite 21 and NiCrBSi-alloy. The abrasion resistances were tested using rubber wheel abrasion apparatus. The wear surfaces were examined. The best results were achieved by M2 tool steel with vanadium carbides.
MoSi2 Coatings on Titanium Alloy Substrates for High Temperature Oxidation Protection of Moved Parts
Authors: Reisel G. , Steinhäuser S. , Wielage B. 
Published: August 2022

Abstract
MoSi2-TiB2 coatings were applied on Ti6Al4V substrates by means of low pressure plasma spraying with and without a surface pre-treatment with plasma-transferred-arc. The coatings were characterized by optical and scanning electron microscopy, X-ray diffraction analysis and hardness measurements. No difference in the microstructure between the coatings was detectable. The microstructure shows the typical lamellar structure of thermal spray coatings with a good embedding of the titanium borides in the matrix. At the interface between matrix and some borides a reaction zone is visible. In comparison to the feedstock powder, the phase composition of the coatings has change, because a great amount of the tetragonal MoSi2 phase transformed into the hexagonal high temperature modification. The content of titanium diboride is lower in the coating. Coatings on substrates with a pre-treatment show a good adhesion to the substrate, while the adhesion of the coatings on the pre-treated substrates is poor.
Circumstantial Theoretical Analysis of Oxide Ceramics Splat Formation
Authors: Solonenko O.P. 
Published: August 2022

Abstract
Within the equilibrium approach, thermophysical foundations were developed which allow one to predict the dynamics of simultaneous deformation and solidification of a metal – oxide droplet impinging on a substrate, with due allowance for conjugated heat transfer under conditions of an ideal contact between the solidifying layer and the base surface. A representative collection of the alumina and YSZ splats was obtained under full control of key physical parameters (KPPs): temperature – Tp0, velocity – up0, and size – Dp, of particle, and temperature –Tb0, of a polished substrate. Without introducing any empirical coefficient, it was obtained quite a satisfactory agreement between the predicted and measured thickness and diameter of splats. In the present paper a comparison of a new solution with known dependences of different authors is carried out. Multiparameter calculations of the YSZ splats characteristics (diameter of splats, rate of cooling and solidification of melt, density of heat flux into substrate, etc.) in a wide range of the KPPs under molten droplets impacted with substrates were carried out.
Impact and Solidification of Droplets Onto Rough Substrates
Authors: Raessi M. , Mostaghimi J. , Bussmann M. 
Published: August 2022

Abstract
We used a three-dimensional model of droplet impact and solidification to simulate the effect of surface roughness on the impact dynamics and the splat shape of an alumina droplet impinging onto a substrate. The substrate surface was patterned by a regular array of cubes spaced at an interval twice their size. Three different cube sizes were considered, and the results were compared to the case of droplet impact onto a smooth substrate. To understand the effect of solidification on the droplet impact dynamics and splat morphology, the simulations were run with and without considering solidification. Comparing the results, we have concluded that solidification plays a major role in determining splat shape on a rough surface. We also present results of the distribution of voids between the splat and the substrate.
Role of the Laser Surface Preparation on the Adhesion of Ni-Al 5% Coatings Deposited using the PROTAL Process
Authors: Li H. , Costil S. , Liao H-L. , Coddet C. 
Published: August 2022

Abstract
The PROTAL process combines a laser surface preparation and the thermal spraying stage. This laser surface preparation avoids some of the traditional drawbacks of the degreasing and sand-blasting stages which is an important factor especially for the notch-sensitive materials. Previous studies showed that deposit adhesion obtained with the PROTAL process is similar to that produced by traditional surface preparation despite the absence mechanical anchorage offered by surface roughness. In order to get a better knowledge of the effects of such a laser treatment, a Ni-5%Al coating was plasma sprayed using the PROTAL process under different surface conditions. The morphology of the impinging splats and adhesion of the deposits were then examined. Removal of the surface contaminants, adsorbates and oxides is confirmed and the role of the laser irradiation on the coating adhesion is discussed.
Design of Alternative Multilayer Thick Thermal Barrier Coatings
Authors: Samadi H. , Coyle T. 
Published: August 2022

Abstract
Increasing the combustion temperature in diesel engines is an idea which has been pursued for over 20 years. Increased combusting temperature can increase the power and efficiency of the engine, decrease the specific fuel consumption, CO and (possibly) the NOx emission rate. At the same time, TBCs should protect the metallic substrate against the corrosive attack of fuel contaminants (Na, V, and S). The most common system used is Yittria Partially Stabilized Zirconia (Y-PSZ). However, in diesel engines Y-PSZ TBCs have not met with wide success. To reach the desirable temperature of 850-900°C in the combustion chamber from the current temperature of 350- 400°C, a coating with a thickness of at least 1mm is required. This introduces different considerations than in the case of turbine blade coatings, which are on the order of 100µm thick. The design of a multilayer coating employing relatively low cost materials with complementary thermal properties is described. Numerical models were used to optimize the thickness for the different layers to yield the minimum stress at the operating conditions while achieving the desired temperature gradient. Abstract only; no full-text paper available.
Effects of Rare-Earth Metal on Microstructure and Corrosion Resistance of Arc-Sprayed Zn-Al-Mg Coating
Authors: Liu Y. , Zhu Z.-X. , Ma J. , Xu B.-S. , Ma S.-N. , Li Z.-X. 
Published: August 2022

Abstract
Cored wires and high velocity arc spraying technique (HVAS) were applied to produce Zn-Al-Mg and Zn-Al-Mg-Re alloy coatings on low carbon steel substrates. And the effects of rare-earth metal on microstructure and corrosion resistance of the Zn-Al-Mg coating were investigated. The microstructures and mechanical properties were studied by SEM, EDS and XRD. The coatings show a typical aspect of layered thermal sprayed material structure. SEM results revealed that the addition of small amount of REM to the cored wires would result in a fine grained structure in the coating layer together with a dense microstructure, which is the reason for the adhesion strength enhancement and the porosity reducing of the coating. And the electrochemical corrosion mechanisms of the coatings were discussed. Chemical analysis of the coating indicated the composition to be Zn-16.5Al-5.9Mg-4.6O-RE (wt%). The phases of the coatings are Zn, Al5Mg11Zn4, MgZn2 and Al3Mg2 mainly, together with oxide ZnO, ZnAl2O4, and MgAl2O4. The electrochemical corrosion behaviors of Zn-Al-Mg-RE coating were investigated in 5%NaCl solution comparing with Zn-Al-Mg coating. Electrochemical measurements in the forms of potential-time and potentiodynamic polarization tests showed that such two coatings behaved excellent electrochemical corrosion resistance in salt solution, and the Zn-Al-Mg-RE coating was much more stable. Electrochemical impedance spectroscopy (EIS) results revealed that small amount of rare-earth metal can not promote to form the passive film but it could enhance the surface property of the coating extraordinarily, which will has a great effect on the corrosion behaviors of the coating. Keywords: Zn-Al-Mg-RE coating; high velocity arc spraying; cored wires; potentiodynamic polarization; electrochemical impedance spectroscopy
Investigation of the Structure of Plasma and HVOF Sprayed Composite Coatings
Authors: Otmianowski T. , Żórawski W. , Skrzypek S. 
Published: August 2022

Abstract
The aim of the research was to compare the size, shape and distribution of the NiCrBSi and Fe2O3 powder particles. Of interest were the chemical and phase compositions of both the powders and structures obtained by plasma- or HVOF-spraying them. The experiments have shown that although the powders differ in structure and particle size, it is possible to use them to obtain composite coatings containing both ingredients. A phase analysis was conducted to study the different phase composition for both spray methods.
Process Maps for Multimodal and Conventional WC-12Co Coatings
Authors: Lima R.S. , Marple B.R. 
Published: August 2022

Abstract
One type of multimodal (comprised of a mixture of nanosized and micronsized WC particles) and two types of conventional WC-Co powders were thermally sprayed by HVOF. Three types of HVOF torches, JP5000, DJ2600- hybrid (H2) and DJ2700-hybrid (C3H6), were employed to produce a total of 66 different WC-Co coatings. For all the coatings produced, the in-flight particle temperature and velocity during deposition, deposition efficiency, hardness and abrasion resistance were measured. These measured properties and characteristics were used to construct process maps (via inverse distance weighting) in order to (i) establish relationships between the various process parameters, properties and performance characteristics and (ii) identify process windows where “optimized” coatings could be produced. It was observed that the multimodal coatings exhibited a much larger processing window for the highest performance, i.e., these coatings demonstrated high abrasion resistance over a broad range of particle temperature and velocity, a characteristic not observed for the conventional coatings. The maps revealed other interesting differences between the multimodal and conventional coatings and among the coatings produced using the various torches. The study demonstrates the value of process maps in producing information for engineering optimized thermal spray coatings.
Elevated Temperature Erosion Studies of Twin Wire Arc Sprayed Cored Wires
Authors: Agrawal M. , Krishnarao V. 
Published: August 2022

Abstract
Twin Wire Arc Spraying of cored wires for wear resistant applications is being increasingly used for industrial applications such as FBC boilers. Two promising cored wires namely Alpha 1800 and Armacor M were selected and sprayed by Twin Wire Arc Spray Technique. The sprayed samples were tested at different temperatures ranging from 3000C to 6000C in a High Temperature Erosion Test Rig using quartz as erodent. The samples were tested at 300 and 900 angles. The erosion behaviour of Alpha-1800 coating was compared with that of base metal Carbon Steel and Armacor M coating. The results showed that the erosion resistance of Alpha-1800 coating was superior than those of Carbon Steel base metal and Armacor M coating at all temperatures and at impact angles of 300 and 900. SEM studies of few erosion tested samples were also carried out to understand the morphology of the eroded regions. Abstract only; no full-text paper available.
Quality control of Thermal Spray Processes through Cost Effective Diagnostic Methods
Authors: Lugscheider E. , Ernst F. , Seemann K. , Pfeifer T. , Dören J. , Zierhut J. 
Published: August 2022

Abstract
Modern thermal spray equipments and diagnostic tools give a lot of relevant process data. Currently only single process parameters (e.g. particle temperature) are recorded and analysed in order to keep the parameters constant. However, even this simple kind of process control is not state of the art in every spray shop. The issue of this publication is the development of a method for prediction of material- and component-properties for thermal spraying. This method will allow an offline process control of the complex coating process. For the development of this kind of process control numerous experiments will be been carried out with both HVOF- and APS-processes using the Particle-Flux-Imaging diagnostic tool (PFI). The PFI-system is the basis for the process control to be developed. In comparison to other diagnostic tools it is easy to handle and cheaper. The set up of experiments and the data evaluation were carried out by means of statistical DOE [1]. The first series of experiments were designed to determine the significant interrelations between these influencing parameters. Based on the results from the first series of experiments, the significant parameters were further manipulated during spraying the second series of experiments The correlation between the coating properties (hardness, porosity) and the main influencing parameters are the basis for the creation of an offline process control.