A coating of blue-black or black zirconium of uniform and controlled thickness on a zirconium or zirconium alloy material is accomplished through the treatment of an amorphous zirconium or zirconium alloy substrate, which may have an altered surface roughness. The treatment of amorphous zirconium or zirconium alloy substrates includes oxidation of the substrates. A zirconium coating of uniform and controlled thickness is especially useful in various applications because the uniformly thick zirconium surface of controlled depth provide a barrier against implant corrosion caused by ionization of the metal substrates.