Tribological behaviour of ZnAl alloys (ZA27) compared with bronze when used as a bearing material with high load and at very low speed

In this paper the tribological behaviour of ZnAl alloy (ZA27) as a bearing material is analysed using experimentally determined Stribeck's curves. Comparisons involving friction coefficient measurements and surface damage observations are reported to illustrate the behaviour of this new kind of bearing material under critical running conditions. Numerous experimental data were therefore compiled and lead to the conclusion that ZnAl alloy is indeed a good substitute material for SAE 660 bronze: a high load (100 bar) at a slow rotation (0.2 rev min −1) could even be supported by a neutral oil without seizure. Although the boundary behaviour of the two materials is similar at 10 and 100 bar, the ZA27 alloy clearly shows superior behaviour at 50 bar.