Babbitt alloys are widely used as bearing components. There are two types of Babbitt alloys, namely tin based and lead based Babbitt alloy. Babbitt alloys possess many beneficial properties such as good compatibility with steel shafts, ability to embed foreign particles, ability to adapt to misalignment in the initial run-in period, and antifriction property. The tribological properties of Babbitt alloys under dry and oil lubrication conditions have been investigated intensively over the past decades. However, there is hardly any investigation carried out on the tribological behavior under water lubrication, especially under sea water lubrication.
Researchers at the State Key Laboratory of Solid Lubrication of the Lanzhou Institute of Chemical Physics of the CAS have investigated the tribological behaviors of Babbitt alloy16-16- 2 (designated as B16 here after) in sea water on a pin-on-disk tester and the corresponding wear mechanisms.
The results indicated that the friction coefficient decreased as the load increased to 30N and then remained at a steady level at high loads, but decreased with increase in sliding speed. The wear rate increased with load, but decreased with sliding speed. The formation of basic lead carbonate Pb3(OH)2(CO3)2 during the sliding process played a critical role in the remaining low friction coefficient in sea water.
The work has received support from the National Natural Science Foundation of China(51075383) and the National Program on Key Basic Research Project of China (973 Program). The findings have been published in Tribology International (44 (2011) 1161–1167).
Tribology International(44 (2011) 1161–1167) Paper
Crystal structure of basic lead carbonate, where the red balls represent O and OH groups, dark gray balls represent Pb atoms and light gray balls represent C atoms.