Plasma Spraying Method Research Articles

Wear energy approach for evaluation of tribological properties of Cr2O3-TiO2 coating

Abstract In the present work, Cr2O3-TiO2 ceramic coating was deposited by atmospheric plasma spray (APS) method. Tribological response of coating was thoroughly examined using two different sizes of SiC abrasives under four distinct loads. Coatings were characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction, Raman spectroscopy and X-Ray Photoelectron Spectroscopy. The coating experienced 31–40% lower friction coefficient at coarser particle size whereas 1.4–1.6 times lower wear rates were obtained at finer particle size. Results were explained on the basis of adhesion-abrasion components of friction. Consequences of formation of a tribo-oxide film and its implications on specific energy for material removal along with wear mechanisms are also discussed. A modified wear energy parameter (WEP) is used and showed good correlation with experimentally measured wear rates and friction coefficient of the coating.

Microstructure and corrosion resistance of novel rare-earth-zirconia doped Y2O3 plasma-sprayed coating

Y2O3 coatings are widely applied in semiconductor etching machines to protect the inner walls of aluminum alloys. This study reports the preparation of yttria-based coatings on aluminum alloy substrates using atmospheric laminar plasma spraying (ALPS) methods. In this study, four yttria-based coatings were designed and tested for their thermal performance, plasma etching resistance, and resistance to laser ablation. The rare-earth-zirconia (RE-ZrO2) doped Y2O3 coating exhibited the best thermal insulation performance, with a thermal conductivity of approximately 0.6 W m−1 k−1 at 600 °C. Plasma etching experiments demonstrated that more rare-earth fluorides were generated on the surface of the RE-ZrO2 doped Y2O3 coating, which weakened the plasma energy. Finally, the lowest etching rate was achieved. Laser ablation experiments demonstrated that the depth of the ablation pit on the surface of the RE-ZrO2 doped Y2O3 coating was shallow, indicating good laser ablation resistance. These results indicate that rare-earth-doped yttria-based coatings provide excellent corrosion protection against plasma etching and laser ablation.

A Comparison of the Tribological Properties of SiC Coatings Prepared via Atmospheric Plasma Spraying and Chemical Vapor Deposition for Carbon/Carbon Composites

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.

The Effects of Combined Treatments of Laser Engraving, Plasma Spraying and Resin Pre-Coating on Improving the Bonding Strength of Titanium Alloy and Carbon Fiber-Reinforced Polymer.

This study focused on effective methods of laser engraving treatment (LET), plasma spraying, and resin pre-coating (RPC) to manufacture the reinforced adhesive joints of titanium alloy and carbon fiber-reinforced polymer (TA-CFRP) composites. The combined treatments contributed to the creation of a better adhesive bonding condition and offer a vertical gap between circular protrusions to form epoxy pins and carbon nanotube (CNT)-reinforced epoxy pins. The bonding strength of the TA-CFRP composite was reinforced by 130.6% via treatments with a twice-engraving unit of 0.8 mm, plasma spraying, and RPC. The original debonding failure on the TA surface was changed into the cohesive failure of the epoxy adhesive and delamination-dominated failure of the CFRP panel. Overall, laser engraving has been confirmed as an effective and controllable treatment method to reinforce the bonding strength of the TA-CFRP joint combined with plasma spraying and RPC. It may be considered as an alternative in industry for manufacturing high-performance metal-CFRP composites.

Investigation of wear behaviour of TiO2 and Al2O3 reinforced YSZ coating

In this study, three different ceramic powders used as thermal barriers were coated on AISI304 stainless steel by the atmospheric plasma spray method. A pin-on-disc apparatus was utilised to investigate the wear characteristics of the coatings. The effect of wear behavior of the addition of Al2O3 and titanium dioxide (TiO2) into the YSZ coating was investigated. Before the wear test, sanding and polishing processes were carried out to ensure that the average surface roughness of the coatings was less than 0.8 µm. The wear test according to ASTM G99-04, was conducted on a pin-on-disc device at a speed of 143 rpm. The test was performed in a dry condition, with a minimum of 8000 cycles. The wear test utilised a 4N load and 6 mm-diameter Al2O3 balls. The surface properties and wear characteristics of the coatings were analysed using a scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) after conducting coating and wear tests. The wear rate of the samples was assessed using optical profilometry. A micro Vickers test equipment was employed to assess the microhardness of the materials. The findings demonstrated that the inclusion of Al2O3 in YSZ led to an enhancement in wear resistance, but the incorporation of TiO2 resulted in a notable reduction in wear resistance.

Protective layers of zirconium alloys used for claddings to improve the corrosion resistance

Abstract Zirconium alloys are used as a cladding material for fuel elements in nuclear reactors. In the case of severe accident conditions, the possible rapid oxidation of zirconium in steam or/and air may result in intense hydrogen generation and hydrogen–oxide mixture explosion. Advanced technologies for increasing the corrosion resistance of claddings are being investigated in two directions: (a) protective coatings on Zr alloys and (b) the use of new materials for claddings. Coatings with silicon may provide a more protective barrier than the ZrO2 films formed on an alloy cladding during nuclear plant operations. These coatings may also serve as a protective barrier during high-temperature accidents. The current work aimed at developing protective coatings with silicon on zirconium alloys. Multielemental Zr–Si–Cr coatings were formed on Zry-2 alloy using the physical vapor deposition (PVD) method. Long-term oxidation tests were carried out under the following conditions: 360°C/195 bar/63 days/water-simulating PWR water. Obtained results show the protective character of formed layers. The material in the form of silicon carbide grains covered with yttrium–aluminum garnet (SiC + YAG) was prepared using the sol–gel method. The formed powder is the main component for coating formation on Zr–1Nb alloy using the method of suspension plasma spraying (SPS).

Defect Engineering for SnO2 Improves NO2 Gas Sensitivity by Plasma Spraying.

Large emissions of nitrogen dioxide (NO2) pose a significant threat to human health, Monitoring its content and implementing timely measures are crucial. Utilizing oxide semiconductors, such as tin dioxide (SnO2), has proven to be an effective way to detect and analyze NO2. The design and preparation of sensing materials with high sensitivity and excellent selectivity is the key to improve the detection efficiency. SnO2 nanopowders with small and uniform particle size, large specific surface area, adjustable defect content, and no impurities were prepared by a new plasma spraying method. The SnO2 nanopowders exhibit outstanding performance in detecting NO2 at a low temperature of 100 °C, the response to 5 ppm of NO2 reaches 48, and the material demonstrates rapid response and recovery times, coupled with excellent selectivity. The exceptional gas-sensitive properties can be attributed to the superior morphology and structure of SnO2. It provides more reaction sites for gas sensitive reactions, fast electron transport, a large number of charge carriers, and improved adsorption of the material to the target gas. This study provides valuable insights into nanomaterial preparation and the enhancement of gas-sensitive properties for SnO2.

Predicting the Corrosion Rate of Al and Mg Alloys Coated by Plasma Spraying Method with Machine Learning

Predicting the Corrosion Rate of Al and Mg Alloys Coated by Plasma Spraying Method with Machine Learning

Thermal barrier coating on Inconel 718: understanding cyclic oxidation kinetics

This study investigates the cyclic oxidation behaviour of a thermal barrier coating (TBC) system applied to Inconel 718 alloy substrates. The TBC comprises a NiCr bond coat and a YSZ top coat, applied using the air plasma spray method. Cyclic oxidation studies involve subjecting the coated samples to repeated heating and cooling cycles, with mass gain measurements taken after each cycle. Vibrational modes and surface morphology are analysed before and after oxidation. Results reveal a gradual increase in mass gain up to the 4th cycle, attributed to interface bonding and diffusion-limited growth. Thermal cycling induces stresses, leading to micro cracking and accelerated oxidation. Oxidation kinetics follows both parabolic and linear laws, with rates decreasing over cycles. Kl values consistently exceed Kp, indicating faster linear growth. The study enhances understanding of TBC behaviour under cyclic oxidation conditions, critical for improving durability in practical applications.

BRIEF OVERVIEW OF METHODS FOR PRODUCING TiSiCN COATINGS AND THE METHOD OF REACTIVE PLASMA SPRAYING

Modern materials science sets itself the task of developing new materials with multifunctional coatings. Materials with such coatings are widely used in various fields of technology: construction and energy, microelectronics, aviation and others. The main reason for the emergence and development of technology for applying multifunctional protective coatings is the desire to increase the durability of parts and assemblies of various machine mechanisms. Wear-resistant hard coatings based on transition metal nitrides and carbonitrides are widely used to extend the life of forging and extrusion dies and high-speed machining tools. Over the past two decades, the widespread use of these coatings has stimulated and supported the development of new processes and materials in an attempt to further improve their properties. Among these coatings, the higher hardness, excellent oxidation resistance and high thermal stability of coatings such as TiSiN and TiSiCN make them the most promising candidates for demanding tribological applications. In addition, TiSiCN coating is a promising material used in marine environments due to its excellent anti-wear and corrosion resistance, as well as high hardness and low friction coefficient. These combinations of properties make TiSiCN coatings potential candidates for protective layers in the automotive and petroleum industries.The article briefly examines the possibilities of producing TiSiCN coatings using different deposition methods to control the properties of the resulting films and the features of the reactive plasma spraying method. The work describes the most common methods and technologies for producing carbonitride coatings currently used. The latest developments and current trends in the field of plasma spray coating technologies are reviewed, taking into account important innovations for industrial coatings. New conclusions that were obtained as a result of fundamental and applied research in physics or chemistry are based on them. The article provides a comparative review of the characteristics of obtaining wear-resistant TiSiCN coatings and the features of using reactive plasma spraying to obtain wear-resistant coatings. Based on an analysis of the literature, it can be argued that the further development of reactive plasma technology is associated with the development of a new resource-saving method for the formation of composite coatings with increased corrosion and tribological characteristics, which corresponds to the development trends of world science.

Mullite/YSZ hybrid thermal barrier coatings plasma sprayed on IN-738LC: Microstructure, phase analysis and oxidation resistance

In the current study, the low carbon Ni-based superalloy Inconel-738 (IN-738LC) was used as the substrate and a metallic bond coat (NiCrAlY) was deposited on the substrate by air plasma spray (APS) method. Subsequently, the layer was coated by a ceramic interlayer Yttria-stabilized zirconia (YSZ) by APS. Finally, as the last ceramic layer, a hybrid ceramic top layer containing mullite and YSZ was plasma deposited on the YSZ interlayer in various compositions such as: 25 wt% mullite/75 wt% YSZ, 50 wt% mullite/50 wt% YSZ, 75 wt% mullite/25 wt% YSZ, and 100 wt% mullite. In order to investigate the oxidation resistance of the produced TBCs, they were heated at 1000 °C for 50 and 100 h. The results showed that the presence of mullite phase is advantageous to hybrid coatings, so that in the 50 wt% mullite/50 wt% YSZ hybrid coating, the percentage of destructive spinel oxides forming the thermally grown oxide (TGO) layer reduced compared to the 25 wt% mullite/75 wt% YSZ coating. Moreover, aluminum oxide is the dominant oxide in the 50 wt% mullite/50 wt% YSZ hybrid coating. However, the further increase in the mullite percentage had no noticeable effect on the reduction of spinel oxides. In addition, the presence of mullite alongside YSZ led to an increase in the hardness of the 25 wt% mullite/75 wt% YSZ hybrid coating (845 HV) compared to the conventional coating including a YSZ layer (680 HV) or a mullite layer (655 HV). The X-ray diffraction (XRD) analysis revealed that the presence of mullite beside YSZ in the coating increases the stability of the coating after oxidation test so that, in the XRD pattern, monoclinic phase was not detected in the hybrid coatings. In general, 50 wt% mullite/50 wt% YSZ hybrid coating provided the best results compared to other coatings. Moreover, with increasing thickness of the hybrid ceramic layer containing 50 wt% mullite to 350 μm, the thickness of the TGO layer decreased to approximately 7 μm. Additionally, it was shown that due to the decrease of chromium and nickel elements in the TGO layer, the level of the spinel oxides in the thick coatings decreases. This led to an increase in the stability of the TGO layer and an extension of the thermal system's lifespan.

Investigation of Yb2SiO5/BSAS/Si coating on Cf/SiC composites: processing and steam corrosion behavior

Environmental Barrier Coatings (EBCs) are used to protect silicon carbide-based composites in the high-temperature steam combustion environment of the latest generation of high-efficiency gas turbine aero-engines. The Yb2SiO5/BSAS/Si coatings with gradient coefficient of thermal expansion were prepared using atmospheric plasma spraying (APS) method on the carbon fiber reinforced silicon carbide ceramic matrix composites (Cf/SiC) composites surface. The coating preparation process parameters were optimized by evaluating the influence of spraying power on the bonding strength, deposition efficiency, and porosity. The corrosion behaviors and mechanism of the optimized Yb2SiO5/BSAS/Si coating was investigated at 1200 ℃ by thermal cycle test in steam conditions. The results indicated that the decomposition of Yb2SiO5 and the conversion of SiO2 to Si(OH)4 were the main corrosion reactions of Yb2SiO5 top coating. Noticeably, the SiO2 component acted as an obvious sign of the reaction front diffusing, forming the clear SiO2-gradient layers. The gradient Yb2SiO5/BSAS/Si coating remained intact after thermal cycles for 500 h at 1200 ℃ in steam conditions which effectively enhanced the resistance of Cf/SiC composites to high temperature steam corrosion.

Microstructure modification of alumina prepared by water-stabilized plasma spraying method using Al-Cu-O reaction

To improve the strength of Al2O3 specimens produced using the water-stabilized plasma spraying technique (WSPSAO), this study investigates the effect of structural modification on the mechanical properties of WSPSAO using the Al-Cu-O reaction between the metal, atmospheric oxygen, and base material. A Cu-powder layer is applied to the specimen surface, melted, and oxidized at high temperatures. It penetrates into the specimen, resulting in significant microstructural modification deep in the specimen. After modification, uniaxial Al2O3, CuO, Cu2O, and CuAl2O4 are formed in the specimen, resulting in a denser and more uniform structure than that of the original material. The bending strength of the coated surface is 145 MPa, and that on the opposite side of the coated surface is 118 MPa, which is 130%–180% higher than the original strength of the base material.

Oxidation and Heat Shock Resistance of Plasma-Sprayed TiC-CoNi Composite Coatings at 900 °C

In this work, the TiC-reinforced CoNi alloy coatings were prepared by the plasma spraying method. Their microstructure, high-temperature oxidation, and thermal shock resistance at 900 °C were studied. The results showed that the CoNi alloy coating exhibited a single phase (c-Co-Ni-Cr-Mo). After adding Ti-graphite mixed powders, the sprayed coating exhibited TiC and TiO2 phases, besides the c-Co-Ni-Cr-Mo matrix phase. For CoNi alloy coating, the main oxidation products were Cr2O3 and CoCr2O4 (NiCr2O4). For TiC-CoNi alloy coating, the main oxidation products were the TiO2 phase, coupled with Cr2O3 and CoCr2O4 (NiCr2O4) phases. The content of oxides increased with the oxidation time. The oxidation weight gain of the TiC-CoNi composite coating was slightly higher than that of the CoNi alloy coating. The formation of TiC could improve the thermal shock resistance of the CoNi alloy coating.

Influence of Spray Angle on Particle Deposition and Thermal Shock Lifetime of Embedded Micro-Agglomerated Particle Coatings

The development of gas turbine technology has led to an increase in the complexity of the geometric shape of the sprayed workpiece. Consequently, it has become more difficult to maintain the perpendicularity of the spraying angle during the spraying process, thereby impacting the structure and performance of the coating. This study uses the atmospheric plasma spraying method to simultaneously spray two types of powder for the preparation of embedded micro-agglomerated particle (EMAP) coatings. The spraying process is conducted at four different angles, ranging from 90° to 30°, in order to analyze the influence of the spray angle on the particle deposition and coating performance. The experimental results demonstrate that the relative deposition efficiency, hardness, and elastic modulus of the EMAP coatings decreased as the spray angle decreased. The porosity exhibited a reduction when the spraying angle dropped from 90° to 50°, followed by a significant rise at 30°. The greatest relative amount of second phase particles embedded in the coating appeared at a spraying angle of 90°, amounting to 10.8%. The smallest amount was found at a spraying angle of 30°, with a relative quantity of 2.2%. Furthermore, the molten droplets of the first phase matrix powder underwent extension and fragmentation along the angular direction at low angles. At an angle of 90°, the maximum average thermal shock life was 40.6 cycles, with the best stability of thermal shock life. The decrease in the spraying angle resulted in a deterioration in both the thermal shock life and its stability.

High-Temperature Oxidation Resistance and Molten Salt Corrosion Study of YSZ, CeYSZ, and YSZ/CeYSZ Thermal Barrier Coatings by Atmospheric Plasma Spraying

Five thermal barrier coatings (TBCs), namely TBC-1 (YSZ), TBC-2 (CeYSZ), TBC-3 (YSZ:CeYSZ = 1:2), TBC-4 (YSZ:CeYSZ = 1:1), and TBC-5 (YSZ:CeYSZ = 2:1), were fabricated using the atmospheric plasma spraying (APS) method. Their oxidation behaviors at 1100 °C and corrosion resistance to molten salts (V2O5 + Na2SO4) at 900 °C were examined. After 100 h of oxidation, the thermally grown oxide layer (TGO) for YSZ primarily contained Cr and Ni oxides with significant internal fractures, presenting a continuous band-like Al2O3. In dual-ceramic configurations, an increase in CeYSZ thickness led to a rise in Al content and reduced Cr and Ni in TGO, with the surface fracture morphing into an internal porosity. Following salt corrosion, YSZ revealed rod-like YVO4 and m-ZrO2 as corrosion products, whereas CeYSZ displayed chain-structured CeO2, CeYO4, and YVO4 combined with m-ZrO2. YSZ coatings underwent notable phase transitions with evident densification, forming a corrosion layer of approximately 10 μm. Conversely, CeYSZ showed a limited phase change, retaining porosity without a distinguishable corrosion layer. As CeYSZ thickness increased from 100 μm to 200 μm in the dual-ceramic structure, salt penetration reduced. Evidently, the dense structure of CeYSZ heightened diffusion resistance against oxygen and corrosive salts, rendering superior oxidation and corrosion resistance over YSZ. By optimizing the thickness ratio between CeYSZ and YSZ, whilst retaining total ceramic layer thickness, the dual-ceramic TBC’s resistance to high-temperature oxidation and corrosion can be enhanced.

Microstructure, wear and corrosion properties of Cu–SiC/WCCo composite coatings on the Cu substrate surface by plasma spray method

In this study, the microstructure, wear and corrosion properties of Cu–SiC/WCCo composite coatings produced on Cu substrates by plasma spray method were investigated. In order to achieve this aim, SiC and WCCo powders were added to copper at different rates such as 5 %, 10 % and 20 % by weight. In order to determine the microstructure properties and phase distribution of the produced coatings, optical microscope, SEM-EDS and XRD analysis were investigated. The reciprocating wear method was used in order to determine the wear properties and the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods was used to determine the corrosion properties. The electrical conductivities of the coating layers were performed according to the eddy current principle. XRD analysis results showed that in both coating types, ceramic particles decomposed in the plasma flame and as a result, binary and ternary metallographic phases were formed. There were significant increases in hardness by adding ceramic particles to Cu, especially with 20 % WCCo additive, the hardness obtained was 82 % higher than the Cu substrate. When the wear properties were examined, both abrasive/adhesive wear types were observed in the copper substrate and coating layers. In all samples, material loss increased as the load increased. Both EIS measurements and Tafel curve results showed that the Cu-5% WCCo coating had the best corrosion resistance among the coatings. When the electrical conductivity results of all samples were compared, the electrical conductivity decreased with increasing rate of carbide in the coating.

Antibacterial effect of Ag-containing hydroxyapatite thin film fabricated by sputtering.

Infections related to joint prosthesis are still a major concern for orthopedic surgeons. Hydroxyapatite (HA) is a useful biocompatible material because of its good osteocompatibility. Antibacterial HA coatings have been fabricated with addition of antibacterial agents such as Ag to HA using the plasma spraying method. However, the plasma-sprayed HA coating suffers from fractures at large thicknesses. The sputter-coated HA thin film has a high density, and has been applied clinically for dental implants. However, there are no extensive studies on Ag-containing HA thin films. The aim of this study was to prepare an Ag-containing HA thin film by sputtering, and evaluate its antibacterial effect and cytotoxicity. The Ag-containing HA thin films were prepared by radio-frequency magnetron sputtering. The films were characterized using X-ray photoelectron spectroscopy, X-ray diffractometry, and scanning electron microscopy (SEM). The antibacterial activities and cytotoxicities of the films were also evaluated. The Ag/Ca molar ratio of the films increased with the Ag ratio in the target. The SEM observation of the hydrothermally treated films showed surfaces covered with globular particles. All Ag-containing HA films exhibited an antibacterial effect against E. Coli. The number of cells of the films decreased with the Ag ratio. The films subjected to the hydrothermal treatment exhibited a higher number of cells than the as-sputtered films. The Ag-containing HA thin film was effective in terms of antibacterial effect, and had a low cytotoxicity in the proliferation of osteoblast cells at a low Ag ratio in the target.

Characterization, mechanical properties, corrosion behavior and bone-like apatite formation ability of fluorine substituted hydroxyapatite coating

Hydroxyapatite (HA) is a non-bioceramic commonly used in human implants in the form of coatings, which are limited in their application by mechanical and wear resistance properties, as well as biodegradability. In this study, fluorine substituted hydroxyapatite (FHA) coatings were prepared on Ti–6Al–4V surfaces by plasma spraying method using a mixture of calcium fluoride and hydroxyapatite powders. The prepared coatings were characterized by X-ray diffraction and fourier transform infrared (FTIR) spectroscopy at different levels of calcium fluoride (3 wt%, 6 wt%, 9 wt%, and 12 wt%). The biocompatibility of the coatings was evaluated by in vitro mineralization experiments. Experimental results showed that at 9 wt% of calcium fluoride, the prepared FHA coatings had better mechanical properties, with improved bond strength (28.2 MPa). The X-ray diffraction patterns of the coatings reflect the fluorine substitution during the spraying process and the 9FHA has the highest crystallinity according to the XRD analysis, which is closely related to the biological activity of the coating. In addition, Potentiodynamic polarisation showed that the sample coated with the 9FHA coating had the highest Ecorr and lowest Icorr, indicating the best corrosion resistance. The FHA coating exhibits faster apatite deposition in simulated body fluid, and the efficiency of apatite deposition increases with the increase of CaF2.

ОЦЕНКА ВЛИЯНИЯ ТЕХНОЛОГИЧЕСКИХ РЕЖИМОВ ПЛАЗМЕННОГО НАНЕСЕНИЯ ПОКРЫТИЙ НА ТОЛЩИНУ ФОРМИРУЕМОГО СЛОЯ

Parts of technological machines, complexes and equipment used in many industries are subject to various types of mechanical wear, which leads to a significant decrease in their durability and an increase in maintenance and operating costs. Promising directions for improving the technologies of plasma application of wear-resistant coatings have been identified. Special attention was paid to the thickness of the functional layer, since when using plasma spraying methods, it has a significant impact on the quality of coatings. (Research purpose) The research purpose is developing mathematical models that make it possible to study the influence of the technological parameters of the plasma application of wear-resistant coatings on the thickness of the functional layer being formed. (Materials and methods) Samples made of 45 steel were used for experimental studies, on which a nickel-based powder PG-CP4 (PR-NH17CP4) was sprayed by plasma method. The current strength of the plasma torch arc, the spraying distance and the consumption of plasma-forming gas were adopted as the main technological modes of plasma spraying of coatings. The thickness of the formed coatings was measured on standardized equipment. Statistical processing of the obtained coating thickness values was carried out using a complete factor experiment using the Box-Wilson method. (Results and discussion). We have developed an experimental mathematical model of the technological process of plasma coating and demonstrated its operability. The criteria used to evaluate the variance of experiments, the adequacy and significance of the obtained regression equations are described. Using the Statistica program, a graphical interpretation of the studied dependencies was given. (Conclusions) Based on the mathematical planning of the experiment, models were obtained that make it possible to establish the relationship between the coating thickness and the specified technological parameters of the plasma spraying process. The results of the analysis of the presented analytical dependencies showed that the thickness of the coating is most influenced by the current strength of the plasma torch arc.