Diamond and diamond-like carbon for tribology and corrosion protection: a retrospective review

Diamond and diamond-like carbon (DLC) films serve as cornerstone materials in surface engineering for tribology and corrosion protection. Diamond films, synthesized via chemical vapor deposition, offer exceptional hardness, thermal conductivity, and chemical inertness, yet face challenges in surface roughness, adhesion, and coating complex geometries. In contrast, DLC films composed of sp2/sp³ hybridized carbon—provide a tunable alternative that bridges diamond’s extreme properties with industrial applicability. This review systematically examines both materials, focusing on engineering design, deposition advances, and performance optimization. For DLC, key strategies include nanocrystalline/multilayer designs, doping, and interface engineering to mitigate high stress and poor adhesion. Tribological enhancement relies on graphitization, C-σ bond passivation, and tribochemistry, while corrosion resistance is achieved through densification, multilayer architectures, and barrier layers. Diamond film discussions cover micro-/nano-/ultrananocrystalline synthesis, morphology-dependent tribology, and inherent sp³-network corrosion resistance. Deposition advances enable conformal DLC films on complex parts and scalable diamond synthesis. By integrating both materials into a unified framework, this work highlights their complementary roles: diamond as the performance benchmark, DLC as the adaptable solution. Future efforts should link material fundamentals to industrial needs, emphasizing interfacial adhesion and extreme-environment performance to broaden applications in aerospace, automotive, precision engineering, and biomedical fields.