This paper presents the results of studies on powders used in wear-resistant thermal spray coatings. The work focuses on the influence of the shape, size, and structure of composite powders containing nickel, iron, and chromium mixed with TiC and dry lubricants such as MoS 2 and CaF 2 . The powders are analyzed using SEM and metallographic methods along with X-ray diffraction. Paper includes a German-language abstract.

Mathematical and computer models of movement and heating of particles in low pressure conditions are developed. The mathematical models are based on the molecular-kinetics theory of gases. A program complex for computer realization of models is developed. It contains a built-in data base of temperature dependent properties of substances, system of processing and graphic visualization of simulation results. For verification of the developed models, computer simulation and experimental measurements of Al2O3 particle temperature and velocity are conducted. These materials were sprayed with Plasma-Technik equipment at pressure 60 mBar in argon. Particle velocity was measured with a special optical device, particle temperature was defined by intensity radiation method. It was established that the developed models are adequate to real process (error of 5-8 %) and may be used for study and improvement of VPS processes.

Ti-implants plasma-sprayed with a hydroxyapatite (HA) coating are widely used. When using an implant the coating quality is characterized by the presence of HA decomposition products and sprayed material structure. This paper investigates the properties of hydroxyapatite coatings and their dependence on the types of plasma spray. The types of hydroxyapatite decomposition on titanium substrates using plasma spray technology are optimized. Paper includes a German-language abstract.

This paper investigates the wear resistance of NiCr-Fe+50(80)%chromium carbide and NiCr-Fe+50%SiC coatings. This is achieved by the plasma spraying of composite powders and the mechanical mixing of powders, followed by an additional treatment with pulses of a plasma jet. The mechanism of wear of the sprayed coatings is also analyzed. Paper includes a German-language abstract.

In this paper, a comprehensive mathematical model is developed for the integrated simulation of the coating plasma spraying process under low pressure. This simulation models powder particles that are heated and moved in a plasma jet, the heat transfer in the "coating substrate" system, and the formation of thermal loads. Basic software is developed for the practical implementation of the model. The process of alumina spraying is simulated. Paper includes a German-language abstract.

The melting of plasma-sprayed thermal barrier coatings (TBC) using highly concentrated energy sources is one of the methods associated with increasing the density of the sprayed material and modifying the phase composition in order to improve the properties of these coatings. This paper presents the results of the investigations into TBC melting using pulse and continuous carbon dioxide lasers. Paper includes a German-language abstract.

On the base of gases molecular and kinetic theory a mathematical model of interaction between powder particles and plasma jet is developed. Three-dimensional description of plasma forming gas density distribution as well as particle motion in the plasma jet are a characteristic property of the model. A software for practical realization of the mathematical model is created. Said software provides the possibility to investigate an effect of low-pressure plasma spraying parameters on particle velocity and coordinates in the plasma jet. Computer simulation of particle velocity for powders from aluminium and tungsten oxides in argon plasma under 60 Mbar is conducted. A "Plasma-Technik" VPS unit is used for testing the developed model. Particle velocity measurement is made by a specially developed optical-electronic unit.

This paper presents a mathematical model of the plasma-spray coating formation process that allows one to estimate bond strength energy, a parameter related to coating quality. Bond strength energy is defined on the basis of particle-substrate or system balance. Unknown quantities in the energy equation are obtained from nonstationary Navier-Stokes equations for velocity field and pressure and from thermoelasticity equations for temperature and stress. Complexities associated with particle spreading and nonlinear hydrodynamics have made it necessary to develop a stable numerical technique.