INFLUENCE OF PULSED DIVISION OF OXIDE SPHEROIDS IN A PLASMA FLOW UPON THE STRUCTURE OF COATINGS

Abstract

The purpose of this part of the research was to study the structural transformations at the transition of particlemicrocomposites from plasma flow into sprayed layer, taking into account grinding of spheroids. The results of investigations of the impulse fission of oxide spheroids in a plasma flow, the granulometric composition of microcomposites of two compositions: SiO2–TiO2, SiO2–TiO2–Al2O3 with an initial particle size of 40–50 μm, 50–63, 63–71 μm and the structure of plasma coatings from them are presented. The process of pulsed fission of spheroids in a plasma stream is found in all the compositions under study and is most intensive in systems of: SiO2–TiO2 (with initial particle size of 40–50 μm and 50–63 μm), SiO2– TiO2–Al2O3 (with initial particle size 40–50 μm). The features of the formation of structural fragments of coatings of various shapes (spheroidized and melted) and composition (completely amorphous, with multilayer shells, including amorphous ones) are studied. It is shown that the proposed technology makes it possible to obtain ceramic coatings with amorphous-crystalline structure, which features are determined by size and composition of initial microcomposites grinding of them directly in the sputtering process allows formation of finer structures in the coatings and, accordingly, significantly changing their performance characteristics and quality (adhesion strength, wear resistance is 3 times higher than that of corundum coatings, porosity is less than 1 %).