**4. Conclusions**

The Ti3SiC2-Pb-Ag self-lubricating composite (TSC-PA) was successfully sintered by spark plasma sintering technique in vacuum, and its friction and wear behavior were investigated by sliding it against Inconel 718 using a pin-on disk setup at RT and elevated temperatures in air. The results found that the TSC-PA was mainly composed of Ti3SiC2, Pb, and Ag. The mechanical properties of the TSC-PA were relatively weaker than that of TSC monolithic. As the temperature increased, the average friction coefficient of TSC-PA/Inconel 718 decreased. The wear rate of TSC-PA exhibited a downward trend and that of Inconel 718 decreased, too, with the rise in the temperature. Interestingly, the wear rate of Inconel 718 was positive wear only at RT and changed to negative wear at other temperatures. The wear mechanism was abrasive wear at low and medium temperatures and turned to adhesive wear at higher and elevated temperatures. The tribochemistry of the sliding contact plays an important part in the transition of the wear theories. It was an effective method of the co-addition of solid lubricants in MAX phases.

**Author Contributions:** Conceptualization, R.Z.; Data curation, H.Z.; Formal analysis, R.Z. and F.L.; Investigation, R.Z.; Methodology, R.Z. and H.Z.; Writing—original draft, R.Z. and F.L.; Writing review and editing, R.Z. and F.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available within the article.

**Acknowledgments:** The author acknowledges the financial support from the "Xinjiang Tianchi hundred Talents Program (Zhang Rui)".

**Conflicts of Interest:** The authors declare no conflict of interest.
