Comparison of the wear properties of modified ZA-12, ZA-27 and two conventional bearing alloys

Abstract

In this investigation. an attempt has been made to examine the wear response of some modified zinc-aluminum based alloys and two conventional bearing alloys at the sliding speeds of 0.65, 1.30 and 1.90 ms(-1), over a range of applied normal pressures. The standard zinc-aluminum based alloys (ZA-12 and ZA-27) and modified with different combination of manganese and silicon alloys have been subjected to a pin-on-disc wear test under dry condition. A white metal (WM-Sn80) and a conventional bearing bronze (Cu-Pb20Sn5) have also been subjected to identical tests with a view to assess the working capability of the modified Zn-Al based alloys with respect to existing ones. The results have shown that the addition of different amount of manganese and silicon improved the wear resistance of ZA alloys, especially at high applied normal loads due to presence of thermally stable and hard MnAl6 intermetallics and primary silicon particles. However, ZA alloys revealed poor wear resistance at high sliding speeds when compared with conventional bearing alloys. At the low sliding speeds and high applied loads, the conventional WM-Sn80 and Cu-Pb20Sn5 bearing alloys attained most inferior wear behavior when compared with that of ZA alloys. The wear characteristics of the alloys have been correlated with their microstructural features. While operating wear mechanisms have been studied through analyses of the wear surfaces and subsurfaces.