Growth of CVD diamond films over bio-medical materials

Diamond films were nucleated on surgically implantable stainless steel, titanium and molybdenum substrates in a microwave plasma CVD reactor designed and built within these laboratories. Three different nucleation processes were adopted. These included mechanical abrasion with micron scale diamond dust, a proprietary subsonic impregnation method and the application of a dc bias voltage to the substrate. A combination of these methods resulted in a dramatic enhancement in the nucleation density on stainless steel. Experiments were also performed on titanium and molybdenum substrates once the optimum nucleation conditions on stainless steel had been ascertained. The films were characterised using a variety of different techniques including SEM, LIMA and XRD. The deposited films were found to be highly faceted and of high elemental purity. XRD analysis demonstrated that carbide phases had formed on each substrate prior to film growth.