Self‐Lubricating Behavior and Tribofilm Formation of SPSed Iron‐Based Composites Reinforced by Graphite/PbO

Conventional iron‐based materials suffer from severe wear and oxidation over a wide temperature range, compromising their service reliability. In this work, iron‐based self‐lubricating composites containing graphite and PbO were fabricated via spark plasma sintering, and their tribological behavior was systematically investigated from room temperature to 400 °C. The results show that the composites exhibit high densification, while the combined incorporation of graphite and PbO markedly affects their microhardness and tribological behavior. At room temperature, the composite containing 5 wt% lubricant exhibits the best friction‐reducing performance under loads of 5, 10, and 15 N, owing to the formation of an effective tribofilm on the wear track. At 400 °C, the composite containing 4 wt% lubricant achieves the lowest coefficient of friction and wear rate. A continuous and compact graphite, Pb‐containing phases, and oxides tribofilm forms at high temperature, reducing material loss and promoting a transition from abrasive and adhesive wear to mild oxidative and abrasive wear. This study shows that composite tribofilm formation can effectively suppress wear of iron‐based materials over a broad temperature range.