Corrosive wear of the Co–Cr–W alloy in liquid zinc

Abstract

The corrosive wearing behavior of the Co–Cr–W alloy in liquid zinc was investigated using a specially designed wearing test machine. Its corrosion rate and wear rate during corrosive wearing process with different conditions were analyzed. The corrosive wearing mechanism of the Co–Cr–W alloy was investigated by analysis on its sliding surface using scanning electron microscopy, energy dispersive spectrometry, and microhardness sclerometer. The experimental results led to the following conclusions: (i) The corrosion of the Co–Cr–W alloy is accelerated by wearing process in the liquid zinc. (ii) The liquid zinc provides obvious lubrication to the sliding surfaces of this alloy and then reduces its wearing rate during the corrosive wearing process. (iii) Its corrosive wearing rate is increasing sharply with increasing temperature of the liquid zinc. (iv) The corrosive wearing of the Co–Cr–W alloy is caused by preferential corrosion of the eutectic phases in this alloy and fatigue cracking of the worn surface. The fatigue wearing of this alloy is directly due to the synthetic effect of strain hardening of the layer on and under sliding surface and serious stress corrosion in the crack tips during the corrosive wearing period.