Development of New Wear-Resistant Surface Coating at Elevated Temperature

Abstract

Because of good oxidation resistance at high temperature and excellent mechanical properties of Ni3 Al and high hot hardncss, and good oxidation resistance of chromium carbide, chromium carbide particle reinforced Ni3 Al matrix composite would possess excellent wear resistance at elevated temperature. Cr7 C3 -NiAl-Ni welding wire was produced by pressureless sintering process in vacuum. When the welding wire was welded on the surface of carbon steel, under the action of the physical heat of arc, NiAl reacted with nickel to form Ni3 Al and carbide particle reinforced Ni3 Al matrix composite was formed on the welding layers. Cr3 C2 was dissolved during welding and dispersed Cr7 C3 was formed, which strengthened the Ni3 Al matrix significantly. The Cr7 C3 -Ni3 Al interface was broadened, and a zone of interdiffusion and a new phase M23C6 were formed, indicating that a good bond has been formed. The hardness of Cr7 C3/Ni3 Al composite at room and elevated temperatures is much higher than that of stellite alloys. In addition, Cr7 C3 /Ni3 Al composite possesses better high temperature oxidation resistance than stellite 12 alloy. So Cr7 C3 / Ni3 Al composite can become an attractive potential candidate for elevated temperature wear-resistant surface material.