Fabrication and Tribological Properties of Ni60 Matrix Solid-Lubricating Composites over a Broad Temperature Range

Ni60 matrix self-lubricating composites (Ni60-MoS2-SrSO4-Cr2O3-BaF2/CaF2) were successfully prepared via cold briquetting combined with vacuum sintering. The wide-temperature tribological behaviors of the fabricated composites against Si3N4 ceramic balls were systematically evaluated from room temperature (RT) to 800 °C, with a particular focus on clarifying the influence of SrSO4 content on friction and wear performance. The results reveal that the composite doped with 10 wt% SrSO4 delivers excellent comprehensive lubrication and wear resistance over a broad temperature range. Benefiting from the synergistic lubrication of multi-phase solid lubricants, this optimized composite maintains a stable and low friction coefficient ranging from 0.150 to 0.380, and its wear rate varies steadily from 9.15·10−5 to 4.79·10−4 mm3/(N·m) at different temperatures. Tribochemical analysis confirms that the in-situ generated SrMoO4 lubricating phase is formed on the worn surface during high-temperature friction, which is responsible for the remarkably reduced friction coefficient and optimal tribological performance of the composite at 600 °C. This study demonstrates that the designed multi-component Ni60 self-lubricating composites possess excellent wide-temperature tribological stability and exhibit great application potential for extreme-temperature friction service environments.