This paper presents new results of studying the influence of parameters of microplasma spraying (MPS) of Zr wire on the structure of Zr coatings. The coating experiments were accomplished in a two level fractional factorial design. Individual particles of sprayed Zr wire and their splats on the substrate were collected under various spraying parameters (amperage, spraying distance, plasma gas flow rate and wire flow rate) and evaluated by Scanning Electron Microscopy (SEM) to establish the effect of particle size and shape on the coating microstructure. The particles were characterized by measurement of their sizes and the obtained results were evaluated in terms of their degree of melting. This was compared with the experimentally observed coating microstructure type and finally correlated to the investigated coating porosity to select the specific MPS parameters of Zr coatings depositing onto medical implants from Ti alloy. It was found that the main parameters influencing the size of the sprayed Zr particles and the porosity of the Zr coatings are the plasma gas flow rate and amperage. It was demonstrated that it is possible to control the porosity of Zr microplasma coatings in the range from 2.8% to 20.3% by changing the parameters of the MPS. The parameters of microplasma spraying of Zr wire were established to obtain medical implant coatings with porosity up to 20.3% and pore size up to 300 μm.

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The paper presents new results of automated path planning for an industrial robot manipulator performing microplasma spraying of coatings on substrates with complex surface shapes. Path planning and automatic generation of the manipulator motion program are performed using data of a preliminary 3D surface scanning by a laser triangulation distance sensor installed on the same robot arm. The automatic manipulator working tool path planning algorithm is based on the choice of the starting segment of the working tool trace as a geodetic line on the surface. An algorithm for optimal spatial curve approximation by a sequence of line segments and arcs has been developed as a part of the automatic manipulator program generation system. The developed algorithms and their software implementation were experimentally tested through robotic microplasma spraying of a protective coating on the surface of a jaw crusher plate, which was then successfully operated for crushing mineral raw materials.

This paper considers the problem of nding the temperature eld in two-layer metallic materials heated by a moving source of radiation. It describes developed by the authors numerical method for solving the problem of heating a two-layer plate by a moving axially symmetric surface heat source with regard to the function of distribution of the power density of the beam for which the program of computation in C ++ was implemented. The calculation results were used for selecting the optimal parameters (speed and power density of the source) of modifying radiation of protective powder coatings on steel substrates.

This paper presents new results of transmission electron microscopy (TEM), scanning electron microscopy (SEM), Xray diffraction (XRD) and atomic force microscopy (AFM) investigation of the structure-phase compositions of coatings on the base of Ni and Co deposited by plasma-detonation on steel substrates after their modification by DC plasma jet irradiation. The phase structures and morphology of precipitation of strengthening phases from solid solution are defined. The irradiation of the coatings leads to the evolution of the structural-phase state of coatings: an increase in the size of the diffusion zone between the coating and the substrate, an increase in the volume fraction of hardening intermetallic phases, the formation of sufficiently homogeneous fine-grained structure in the irradiated coatings and, consequently, a significant increase of hardness, corrosion and wear resistance of modified coatings. There is a mutual penetration of the substrate main element Fe in the coating and base coating elements (Ni and Co correspondingly) into the substrate as a result of the coating treatment by a pulse DC plasma jet.

This paper presents the method of microplasma deposition of biocompatible coatings using an intelligent robotic system for plasma processing. The two-layer coatings from biocompatible materials, namely from titanium wire and hydroxyapatite powders are sprayed on the surface of titanium substrates. The synthesis of hydroxyapatite powder suitable for applying biocompatible coatings onto medical implants is provided by chemical precipitation. Optimization of the synthesis parameters is carried out by the mathematical modelling method. The porosity of coatings is controlled by changing the spraying regime. The use of the intelligent robotic system for plasma processing allows movement of a robot arm along a given 3D-trajectory and accurate maintenance of plasma spraying parameters: the trajectory and travel speed of the plasma source, an angle between the sprayed surface and the plasma jet, and the distance from the plasma source to the surface of substrates. The composition and regimes of microplasma spraying of biocompatible coatings using an intelligent robotic system for plasma processing have been developed.

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