Effect of surface modification on wear resistance of TC6 titanium alloy for pump plunger

Modification layers for improving wear resistance of TC6 alloy were prepared using a plasma nitriding, a double-glow plasma Mo surface alloying and a cathode arc ion plating TiN. The tribological properties of TC6 substrate, Cr12MoV steel and those modified layers on the TC6 alloy surface, sliding with GCr15 steel or copper alloy (ZCuSb3Ni3Zn3Pb20P) in aviation kerosene, were comparatively researched. Besides, the effect of roughness on abrasion behavior of friction pairs by post-polishing treatment was discussed. The results indicate that sliding in aviation kerosene, the wear resistance of TC6 alloy is obviously worse than that of Cr12MoV steel with GCr15 steel ball counterpart. The surface modification of TC6 alloy, such as plasma alloying Mo, plasma nitriding, ion plating TiN, is markedly enhanced the surface hardness and wear resistance, however wear resistance of the modified TC6 alloy is inferior to that of Cr12MoV steel. Plasma nitrided and subsequently properly polished TC6 alloy is not only obtained lower surface roughness and lower friction coefficient, but good wear resistance, and has preferable tribological properties than Cr12MoV steel.