The tribological experiments of different metal frictional pairs were investigated by using MMU-5G friction and wear tester under oil-lubricating condition with serpentine powder additives. The upper and lower specimen pairs were 45 steel/45 steel, 45 steel/HT200 cast iron, HT200 cast iron/45 steel, HT200 cast iron/HT200 cast iron, respectively. Serpentine powder used as oil additive was characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD). Applying SEM and EDS, the surface morphologies of self-repairing coatings and their chemical compositions were detected. The test results revealed that self-repairing coating could be generated on 45 steel specimen surfaces. However, no obvious self-repairing coating formed on the worn surface in all tests which is mainly due to the unique microstructure of HT200 cast iron and the segregation effect of graphite.