An oxide coating is formed on zirconium or zirconium alloys of refined microstructure by a process comprising at least the step of inducing an appropriate altered surface roughness such that subsequent oxidation results in a uniformly thick oxide coating. An oxide coating of uniform and controlled thickness is especially useful on orthopedic implants of zirconium or zirconium-based alloys to provide low friction, highly wear resistant surfaces on artificial joints, such as hip joints, knee joints, elbows, etc. The uniformly thick oxide coating of controlled depth on oxide coated prostheses provides a barrier against implant corrosion caused by ionization of the metal prosthesis.
