Abstract: Process for simultaneous electrodeposition of at least a two component alloy system of cobalt and chromium on a substrate, by providing an aqueous solution of divalent cobalt and trivalent chromium ions and containing ethylenediaminetetraacetic acid, at a pH of about 3 to about 5, electrolyzing the solution in an electrolyte cell containing an anode and a cathode, and codepositing cobalt and chromium on the cathode, e.g. titanium, as substrate. According to a preferred embodiment molybdenum-containing ions are also added to the electrolyte, resulting in codeposition of an alloy of cobalt, chromium and molybdenum. In another embodiment, a calcium phosphate ceramic such as hydroxyapatite (HA)is added to the above electrolyte solution, resulting, e.g. , in a codeposit of the calcium phosphate material, e.g. HA, and an alloy of cobalt, chromium and molybdenum.

Abstract: A metal substrate, e.g. titanium, having a calcium phosphate coating, particularly hydroxylapatite, and containing a metal such as cobalt, codeposited on the substrate by electrolyzing a cobalt salt, particularly cobalt sulfate, liquid electrolyte having a calcium phosphate material, particularly hydroxylapatite, suspended therein, employing a cobalt anode and the metal substrate as cathode. The particles of cobalt so codeposited with the particles of calcium phosphate material, e.g. hydroxylapatite, hold the latter particles strongly on the substrate metal. If desired, a second coating of the pure calcium phosphate material, e.g. "hydroxylapatite", optionally can be applied over the codeposited hydroxylapatite-cobalt coating. The calcium phosphate coated metal substrate of the invention, particularly the codeposited "hydroxylapatite"-cobalt coating, on a titanium or cobalt-chromium substrate, has particular value for application as medical implants, e.g.