The paper presents optimization of processes for obtaining maximum content of tetragonal phase in the initial material and thermal barrier coatings (TBC) based on zirconium dioxide and hafnium oxide. Results of the investigations on phase composition of oxide HfO 2 – ZrO 2 – Y 2 O 3 system have been given in the paper. The system represents a microstructure which is similar to zirconia dioxide and transformed for its application at 1300 °C. The paper explains a mechanism of hafnium oxide influence on formation of the given microstructure. The research methodology has been based on complex metallography, X – ray diffraction and electron microscopic investigations of structural elements of the composite plasma coating HfO 2 – ZrO 2 – Y 2 O system. In order to stabilize zirconium dioxide dopant oxide should not only have an appropriate size of metal ion, but also form a solid solution with the zirconia. This condition severely limits the number of possible stabilizers. In fact, such stabilization is possible only with the help of rare earth oxides (Y 2 O 3 , Yb 2 O 3 , CeO 2 , HfO 2 ). Chemical purity of the applied materials plays a significant role for obtaining high-quality thermal barrier coatings. Hafnium oxide has been selected as powder for thermal barrier coatings instead of zirconium dioxide due to their similarities in structural modification, grating, chemical and physical properties and its high temperature structural transformations. It has been established that plasma thermal barrier HfO 2 – ZrO 2 – Y 2 O 3 coatings consist of one tetragonal phase. This phase is equivalent to a non-equilibrium tetragonal t' phase in the “zirconium dioxide stabilized with yttrium oxide” system. Affinity of Hf +4 and Zr +4 cations leads to the formation of identical metastable phases during rapid quenching.

The paper presents investigation results pertaining to the influence of such parameters as plasma jet (current, spraying distance, expenditure of plasma-forming gas – nitrogen), fraction composition of an initial powder and cooling rate with compressed air on characteristics of anti-meteoritic coatings. Due to simplicity of the apparatus design and its tangible efficiency a method of plasma spraying in aerial environment is mainly used presently for application of ceramic layer on the basis of partial stabilized zirconium dioxide. The main peculiar feature of plasma anti-meteoritic coating structure is formation of some controlled porosity in order to increase permissible deformations in ceramics. The idea to create structures with controlled porosity is based on the fact that porous bodies are less liable to macroscopic scattering of cracks under the action of internal stresses due to slowing-down or deviation of an extending crack by pores and also due to low elasticity modulus of porous materials in comparison with compact ones. Methodology of the executed research works has been based on complex metallographic, X-ray and electronic and microscopic investigations of anti-meteoritic coatings on the basis of zirconium dioxide. In order to ensure high impact strength the structure of anti-meteoritic coatings on the basis of zirconium dioxide should contain more than 90 % of tetragonal phase of zirconium dioxide and not less than 10 % of monoclinic phase. In this case phase composition and impact strength of coatings depend on chemical composition and production method of the powder. Optimization of parameters for spraying anti-meteoritic coatings based on zirconium dioxide has been carried out according to obtaining maximum coefficient of material usage and maximum content of tetragonal phase of zirconium dioxide in the sprayed coatings.

The purpose of the presented paper is to optimize technological parameters of hardening high-energy processing used for sprayed coatings made of materials based on oxide ceramics with inclusions of solid lubricant. The paper presents results of the investigations on influence of power density and total number of laser irradiation impulses in a spot treatment on thickness of treated coating layers made of materials based on oxide ceramics. The considered wear-resistant coatings require increased cohesive and adhesive strength. Therefore, the total number of impulses should ensure melting and sealing of the coatings along the whole thickness that will fully contribute to obtain hardened nano-crystalline and amorphous structures. The work is based on complex metallography, X-ray diffraction and electron-microscopic investigations on modified structural elements of composite coatings being treated with highly concentrated energy sources. The following main processes of hardened plasma coating formations have been revealed in the paper: com paction of sprayed materials due to thermal and shock-wave impacts of laser irradiation impulses. In this case material porosity is decreasing, cohesive and adhesive strength of coatings is increasing, grain structure is crushed, amorphous and nano-crystalline phases of higher strength are formed all these facts are evidenced by an increase in average micro-hardness of deposited compositions. Duration of thermal laser irradiation impulse impact on the material is sufficient to activate chemical processes in the boundaries of main phases of the composite coating. This leads to formation of finely dispersed (including nanoparticle size) compounds that strengthen boundaries of the main phases and the coating as a whole. This is confirmed by the results of an X-ray diffraction analysis.

The paper considers a technology for composite powder based on zirconium dioxide which is partially stabilized by cerium oxide. The powder makes it possible to spray thermal coatings with high thermal resistance.

Researches of powder production process are carried out on base HA + ZrO 2 and adapted technological characteristics of plasma bioceramic coatings on the basis of this materials.

The paper describes an investigation of the structure, chemical and phase composition of wear resistance coatings on the basis of oxide ceramics with inclusions of solid lubrication.

The process has been investigated and technological parameters for spraying gradient plasma coatings on the basis of zirconium dioxide stabilized with ytterbium dioxide have been optimized in the paper.

The paper presents an oxide ceramic material with addition of solid lubricant which has good technological characteristics and which is able to form high wear-resistant plasma coatings with low friction coefficient.

The paper presents a method for obtaining diffusion alloyed powders on the basis of austenitic steel.