Strength and Crack Resistance Structural Criteria of Composite Coatings Produced by the Method of Multi-Chamber Detonation Spraying

The essential task of modern industry is to increase the reliability and durability of products. One of the promising ways to increase the products operational durability is the ceramics and cermets powders functional coatings application to the working surfaces by the method of high-speed multi-chamber detonation spraying. The objective of the given paper is to determine the regularities of the influence of structural-phase features in the formed material of functional cermets coatings of metal parts on their strength characteristics and crack resistance, while taking into account structural criteria that will provide the required set of strength and crack resistance properties. The method for deep and detailed analysis of the structure features, morphology and distribution of phase particles, their stoichiometric composition, substructure parameters, dislocation density in the coating material obtained due to multi-chamber detonation spraying has been developed in this paper. The research of detonation coating material was carried out using transmission electron microscopy (TEM) on JEM-200CX instrument (produced by JEOL company) with the accelerating voltage of up to 200 kV. The prospects of using the method of multi-chamber detonation spraying on various materials (steel, copper, aluminum, titanium) and alloys are shown on the basis of the research results. A number of composite coatings made of aluminum and zirconium ceramics; chromium, tungsten carbides have been obtained. It has been defined that changes occur in the ratio of the following parameters: microhardness, pore volume fraction, phase composition, distribution of dispersed phases, grain, subgrain, dislocation structures, etc, under different processing modes in the surface layers and corresponding change in the modes of detonation spraying.