In-situ growing amorphous carbon film with attractive mechanical and tribological adaptability on PEEK via continuous plasma-induced process

Abstract The a-C:H films with plasma-induced in-situ transition layer were fabricated on Polyether ether ketone (PEEK) substrates by continuous acetylene plasma treatment, using plasma-enhanced chemical vapor deposition (PECVD) method. Microstructure, chemical bonding state, mechanical and tribological properties of the as-fabricated a-C:H and Cr/a-C:H films were systematically investigated. Based on these, a self-consistent in-situ growth mechanism is discussed in detail. Results show that the a-C:H films with plasma-induced in-situ transition layer endows the treated PEEK substrates high hardness, toughness and adhesion strength. In addition, the interaction of in-situ transition layer and amorphous enhanced phase show better load-bearing capacity in the scratch and tribological test. The failure mechanism of scratch test is proposed and wear mechanisms in vacuum, air and seawater environment are analyzed. Importantly, this novel plasma-induced in-situ transition layer structure is a further development of the concept of gradient coatings in its application to polymers.