A Little Alkali Solution Triggering a Qualitative Change of <scp>PEEK</scp>‐Based Composites From Brake‐Like Materials Into Self‐Lubricating Ones

ABSTRACT A series of silica (SiO 2 ) microspheres filled poly‐ether‐ether‐ketone (PEEK) composites were prepared by hot‐pressing, and their tribological performance when sliding against stainless steel was studied by drop‐lubricated with sodium hydroxide (NaOH) solution compared with deionized (DI) water. Interfacial chemical reactions were mainly investigated, and the microtopography, chemical structures, and compositions of the worn surfaces of the tribo‐pairs were also systematically characterized. The results showed that compared with DI water, 2 mol/L NaOH solution played a significant role in improving the wear resistance of 30 wt% SiO 2 microspheres filled PEEK and can reduce the wear rate by 79%. COF was reduced from 0.45 to 0.12, the lubricity improving by 73%. In comparison to neat PEEK, the wear resistance of the above composite can enhance by one order of magnitude, and COF can reduce by 45%. This work provides powerful evidence for the direct positive impact of interfacial chemical reactions on the tribological behaviors.