Re‐attainable lubrication films at 500°C converted through the positional polymerisation of DCDPS on the preset Na₂S coating

Abstract

Adding solid DCDPS into the high-temperature system, it would be gasified by the ambient temperature and convert the preset Na 2 S coating into polyphenylene sulfide sulfone lubrication films through positional polymerisation. During the 10 min ball-disk tribological test at 500 C, lubrication films would form on the disk surface initially, then attach to the friction points of the balls, producing transfer films that significantly reduce the coefficient of friction (COF) and wear, especially the wear on the steel disk. In the 30 min test, the lubrication could be re-attained with COF not exceeding 0.2 by simply supplementing DCDPS again at 10 min. This result can be inferred as the repolymerisation between the degradation products from the earlier stage and the newly added DCDPS. Thus, the position of the lubrication films formed during the high-temperature friction could be controlled by preset coating, and the high-temperature lubrication could be extended or re-attained by replenishing the other monomer.