Bonelike Coatings onto Ceramics by Reactive Magnetron Sputtering

Bonelike coating of partially carbonated, calcium hydroxyapatite onto strong ceramics and metals is one of the current objectives in biomaterials science for the development of bioactive implant materials. We recently accomplished bonelike apatite coating onto ceramic alumina by the newly developed reactive rf‐magnetron sputtering method, which was undertaken in a mixed CO 2 /Ar gas. The key of this method is the use of calcium phosphate glass targets with much lower Ca/P ratios than the stoichiometric value of hydroxyapatite. Surface analyses by XRD, EDX, and FT‐IR identified the formation of bonelike carbonated calcium hydroxyapatite, in which CO 2‐ 3 ions occupied the lattice positions of PO 3‐ 4 . The bioactivity of the coated ceramic materials was confimed by in vitro experiments on the bonelike crystal growth on their surfaces in a simulated body fluid, and the growth rate on the coated layers was experimentally proved to be much faster than that on uncarbonated hydroxyapatite