Comparative study of saturating power boriding media of different composition

Abstract

Comparison of the ability of saturating media for Boriding based on boron carbide and amorphous boron and mixtures for simultaneous saturation of boron, chromium and titanium. As the object of study were selected boride coatings on carbon steels: 45 and U8A. Borating made from powder mixtures in a chamber furnace. The Microstructure and the thickness of the diffusion coatings was investigated on cross microsections by optical microscopy. Identification boride phases produced by the "color etching" and with the help of X-ray diffraction. It is shown that while saturation with boron, chromium and titanium carbon steel, diffusion processes are much more intense. Introduction inside the boriding mixture carbide-forming elements such as chromium and titanium, facilitates significant acceleration of diffusion of boron within steels 45 and U8A. With simultaneous multicomponent saturation with boron, titanium and chromium the rate of formation of the diffusion layer on the carbon steels higher than under one-component boriding. In the case of multicomponent saturation boron together with the strong carbide-forming elements (chromium and titanium) increase the carbon content of the saturated carbon steel of 0.45 to 0.8 wt.% has little effect on the formation of a diffusion layer in contrast to the one-component boron saturation. In case of the one-component boriding carbon steels, content the carbon of the steel is significantly affects both the thickness and of microstructure of the boride coating. With simultaneous saturation the carbon steels of boron, titanium and chromium carbon content of the steel is practically no effect on the diffusion coating thickness.