Pyrocarbon coated bone implants

A method of making a bone implant, which method comprises the steps of:

• creating a substrate of structurally strong isotropic graphite of the shape desired for a bone implant,
• coating the substrate with a surface layer of microporous isotropic pyrocarbon of a density between about 1.7 and 2.1 g/cm3 and a hardness of at least about 200 DPH, which layer has an average thickness of at least about 100 microns and has an average surface roughness (Ra) of at least 2 microns, said surface being formed of aggregate carbon particles having an average size of about 0.15 to 0.5 micron and adjacent void regions of an average size of about 0.05 to 0.10 micron, which void regions are present in an amount to create an overall surface porosity of about 2 to 10%,
• using physical vapor deposition (PVD) to coat a first metal layer at least about 2 microns and not greater than about 10 microns thick atop a designated portion of said isotropic pyrocarbon layer while leaving a portion of said pyrocarbon layer uncoated, said coating being applied by PVD from a vapor atmosphere so that such first metal layer penetrates into said microporous pyrocarbon to create a secure bond and presents an exterior surface smoother than said underlying pyrocarbon surface, and
• thermal-spraying a second layer of a biocompatible metal onto at least a designated portion of said first metal layer using a device that melts fine metal particles to produce minute molten globules at least having liquefied outer surfaces to thereby provide an outermost, textured, second metal layer having an average thickness of at least about 25 microns and a texture that enhances attachment of said outermost metal surface to cortical bone, said metal of said first layer and said metal of said second layer having melting points within about 200° C. of each other so that said thermal-sprayed particles fuse to said first metal layer.