Destruction electrospark deposits during Joule heating of base metal

Abstract

Electrospark coating deposited on the surfaces of machine parts is a common surface hardening method. Hard materials are normally used for depositing to improve wear resistance or other properties. In this investigation electrospark deposition intended for use as micro-alloying of welds by deposition on to the surface of the base metal and in this case it remelts completely. Intense heating and destruction occurs before remelting, which changes the chemical composition of the melt. The aluminum and titanium coatings is shown to deteriorate at 500 to 650 C generating a liquid phase due to eutectic available in both metals in this temperature range. Most of titanium and aluminum oxidized at that. It is found that a solid layer, appears after electrospark depositing using both coatings. For aluminum coating, after high-temperature heating, a thicker white layer appears with the same microhardness level as that of the base metal, and a thin layer of partial decarburizing. Fusion sectors are detected in the titanium coating that are harder than the base metal and have a dendritic structure, followed by a thin zone of complete decarburization and quite an extended zone of partial decarburization. © Published under licence by IOP Publishing Ltd.