Deposition of CVD Diamond Coatings on Carbon Fiber Composite Substrates

摘要

Boron doped diamond coatings are used in electrochemistry, due to the high overvoltage for oxygen generation. Niobium is often used as bulk material, but also diamond deposition on titanium was demonstrated. For metallic bulk materials corrosion can take place in case of defects in the diamond coating. This problem can be avoided by using carbon based substrates. Diamond deposition on carbon substrates is difficult, because atomic Hydrogen needed for diamond growth attacks graphitic and amorphous carbon. These reactions have the effects that carbon in the substrate is etched and the amount of atomic hydrogen needed for diamond growth is reduced. To reduce the carbon etching on the substrate, the duration till diamond layer formation should be short. By controlling the diamond deposition conditions, boron addition and seeding with diamond prior to deposition, the formation of diamond coatings on carbon fibre composites (CFC) is possible. Electrochemical measurements of the boron doped diamond coatings verified the excellent electrochemical properties of the samples, e.g. good electrical conductivity, high overvoltage for oxygen and hydrogen but also chemical inertness.