Metallographic Studies into the Structure and Physicomechanical Properties of Coatings Obtained Using Plasma Methods

The results of metallographic studies into the structure of plasma coatings obtained from a mixture of high-chromium alloy cast irons and nickel-chromium alloys are presented. It is established that the structure of these high hardness coatings consists of carbides and chromium borides having a ledeburite-austenite base. When plasma spraying is followed by reflow melting, the structure of reflowed coatings becomes homogeneous and finely dispersed, resembling that of the initial powder. In plasma coatings, the distribution of elements is uniform; however, when self-fluxing coatings melt, they are redistributed. The highest wear resistance was achieved in coatings obtained via plasma spraying followed by the reflow melting of powder compositions PR-Ni70Cr17Si4B4 (23%) + PG-FBYu 1-4 (73%) + Al (4%) and plasma surfacing with the use of powder compositions PG-FBYu 1-4 (70%) + PR-Ni70Cr17Si4B4 (27%) + Ti (3%).