Effect of nano-structured factors on the properties of the coatings produced by detonation spraying method

Abstract

Surface treatment by detonation spraying of composite coatings significantly increases the service life of structures. The demanded direction of application of this method is spraying of powders of various systems. The purpose of this paper is to study the structure (phase composition, microhardness, grain and subgrain structure, dislocation density, dispersed micro- and nano-particles, their composition, and distribution), and the properties of metal-ceramic coatings: Al2O3–Ti; Al2O3–Al; ZrSiO4 sprayed on various substrates materials (aluminum, titanium). The investigations of structural-phase state of coatings were carried out at all the structural levels using comprehensive methodological approach including optical metallography, analytical scanning electron microscopy, X-ray structural phase analysis, as well as transmission micro diffraction electron microscopy. As a result of the carried out work the experimental data on the full complex of structural and phase parameters of coatings, sprayed at different modes of cumulative-detonation spraying, were obtained. The obtained results showed the prospects of using multi-chamber detonation spraying, which ensures the necessary complex of mechanical properties of coatings by forming the most favorable structure. The surface treatment of metals by the detonation spraying of coatings makes it possible to obtain composite surface layers with high operational properties. The matrix of such coatings is characterized by a significant dispersion of the substructure, the formation of strengthening phases of nanoscale dimensions and a uniform distribution of dislocation density.