Seizure behaviour of some selected Pb-free engine bearing materials under lubricated condition

Under severe operating conditions seizure can occur in engine bearings. Therefore it is important to study seizure behaviour of selected Pb-free bearing materials that may replace the conventional Pb-based materials. Seizure tests were carried out using a block-on-ring test configuration by stepwise increasing applied load at a constant rotational speed using base oil and also fully formulated engine oil respectively. The bearing materials are ranked in terms of friction and seizure load. Al-Sn based lining without overlay shows higher friction and lower seizure load in both oils. Polyamide-imide based overlay containing MoS2 and graphite and Pb-based material show no sign of seizure. For Sn-based overlay plated materials seizure load is higher in fully formulated engine oil than in base oil.