Process for forming diamond-like carbon coatings on metal surfaces to produce increased resistance to penetration, abrasion, and corrosion. A Ni/P coating is formed on an uncoated metal workpiece by-electroless deposition. While the workpiece is heated to harden the Ni/P coating, a vaporized stream of silicon is directed onto the Ni/P coating and the stream of silicon over the Ni/P coating is bombarded with an ion beam such that a NiSi.sub.2 layer is formed at the interface of the Ni/P coating and silicon and a silicon overlayer is formed over the NiSi.sub.2 layer. A vaporized stream of carbon-containing precursor molecules is directed onto the silicon overlayer such that a film of the precursor molecules condenses on the silicon overlayer. The film of precursor molecules is bombarded with an ion beam sufficiently to form a layer of diamond-like carbon on the silicon overlayer. A Ni/B solution or Ni/SiC solution can be used instead of the Ni/P solution, and germanium can be used instead of silicon.