Exploring a diamond film to improve wear resistance of the hydraulic drilling impactor

摘要

Ultra-deep drilling suffers from arduous conditions, and wear failure of hydraulic drilling impactor may trigger catastrophic accidents. This work endeavored to explore a diamond film to prevent hydraulic drilling impactor from the wear failures and revealed its modification mechanism. a-SiC layer was employed as an interlayer, and CH4/H-2 ratio, as critical parameter, was adjusted to optimize the film structure. The film deposited at 1.0% (CH4/H-2 ratio) exhibits the admirable combined performances and have three structural characteristics: the highest preferred orientation of (111) plane, the highest content of sp(3)-C, and a low surface roughness. The optimized coating showed excellent tribological properties, The modification mechanism of the diamond film for the abrasive resistance may originate from synergistic effects of (i) the contact surface flattening that lowers the frictional coefficient and wear rate, (ii) two-phase lubricant that enhances boundary performance, and (iii) self-lubricating transfer layer that extends the service life.