Effect of Structure on the Properties of Composite Cr3C2 + NiCr Coatings

Abstract

Increase of the reliability and durability of products, the operating properties of which are determined by the properties of their working surfaces and make it possible to use them in extreme conditions: high temperature and pressure, intense wear by friction, alternating loads, etc. There are various technological solutions that provide the necessary properties of functional surface layers depending on the requirements for the products. The proposed technology for the creation of surface layers using a detonation gun sprayer of the original design, developed in the E. O. Paton Electric Welding Institute. This method allows meeting the increasing demands on the quality of the coatings obtained, energy and material efficiency, etc. The goal of the work is to study the phase composition and microstructure and their influence on the properties of cermet coatings of the Cr3C2–NiCr system sprayed in various modes using a multi-chamber detonation device. An integrated research approach was carried out, which made it possible to obtain the data on the structure and phase composition of the coatings under study by the methods of light, scanning and transmission electron microscopy. The obtained data on structural parameters made it possible to carry out analytical evaluation of the level of strength and crack resistance of the coatings obtained. With an increase in heat input per unit volume of sprayed powder the level of decarbonization of carbide particles increases. Evaluation of the local inner stresses of the coatings allowed us to determine that it leads to formation of the critical zones with high tendency of crack formation.