THE EFFECT OF THE STRUCTURE OF PLASMA-SPRAYED COATINGS IN THE TiB₂–(Fe–Mo) SYSTEM ON MECHANICAL AND TRIBOTECHNICAL PROPERTIES

Abstract

The structure, mechanical properties, and the wear-resistance of TiB₂–(Fe–Mo) plasma-sprayed coatings are investigated. Composite powders in the TiB₂–(Fe–13 wt.% Mo) system with 20, 40, 60, and 80 wt.% of the Fe–13 wt.% Mo alloy were produced by vacuum sintering with subsequent grinding. The developed powders are conglomerates that contain both refractory and metallic phase. During plasma-spraying of coatings of TiB₂–(Fe–13 wt.%Mo) powders, a coating with heterophase structure, which consists of the Fe-Mo alloy and titanium diboride grains, is formed. The effect of the microstructure of plasma-sprayed coatings on the wear-resistance under abrasive wear and dry sliding friction conditions is studied. The scleroscopy revealed an insufficient strength of TiB₂–20 wt.% (Fe–13 wt.% Mo) coatings and their poor adhesion to the substrate, resulting in the extremely gross wear, when friction. It is found out that, due to the optimal ratio of refractory and metallic phases, the TiB₂–40 wt.% (Fe–13 wt.% Mo) plasma-sprayed coating possesses high wear-resistance under abrasive wear and dry sliding friction conditions.