the invention provides a method for producing bioinert biocompatible diamond particles / polymer composites or any other matrix / diamond particle composites , even if not biocompatible with outstanding mechanical , tribological , and biological properties , the method comprising selecting a polymer having a melting temperature below about 300 c ; mixing diamond particles with the polymer to form a liquid mixture , poring the liquid diamond particle / polymer or any other diamond particle / matrix composite in liquid form into a mold and then causing the composite to sinter with the diamond particles densely and uniformly distributed through the bulk and surface of the composite , such that the diamond particles distributed on the surface can form a diamond layer covering the surface .