Frictional behaviors of some nitrogen ceramics in conformal contact with tin coated Al-Si alloy, steel and SiCp/Al-Si composite

摘要

The frictional behavior of some nitrogen containing ceramics, such as silicon nitride, alpha sialons and beta sialons as journal materials were studied in conformal contact with a tin coated Al-Si alloy (Al-Si/Sn), forged 1141 steel and a castaluminum matrix composite with silicon carbide reinforcement (cast MMC) as bearing materials while lubricated with SAE 10W30. A case hardened 1016 steel was also tested with the Al-Si/Sn and cast MMC bearings under the same conditions. The friction values of the ceramic and the steel journal wear pairs were compared and their frictional behaviors were evaluated.Silicon nitride and one of the beta sialons exhibited higher load supporting capacities than the others when they were in contact with the 1141 steel bearings. The journal surface roughness was found to be very important when the journal were in contactwith the Al-Si/Sn bearings. The frictional behavior of the ceramics and cast MMC pairs and the steel and cast MMC pairs were controlled by different wear mechanisms, namely for the former, hard particle pull-out and matrix plowing and for the latter, iron transfer from the journal to the cast MMC bearing surface.