Effect of ZDDP on friction in fretting contacts

The effect of ZDDP on fretting wear was investigated in a ball on flat machine. The results confirm previous work that anti-wear agents may reduce friction and wear in fretting contacts. It was further found that temperature, adsorption time, base oil polarity as well as the presence of other surface active additives in the oil were all important parameters affecting the ability of ZDDP to protect the surfaces against fretting wear.

► Base oil polarity and the presence of other polar molecules influence the effect of ZDDP in fretting contacts.
► Effect of ZDDP less pronounced at higher temperatures (80̊C).
► Waiting time (adsorption kinetics) is an important parameter.