Diamond deposition on carbon substrates is challenging, because atomic hydrogen necessary for the low-pressure diamond growth, attacks the graphitic and amorphous carbon of the substrate. As a consequence the reduced amount of atomic hydrogen causes a decrease in diamond growth rate and quality. To reduce the etching effects, the duration till a dense diamond layer is formed should be as short as possible.
By controlling the diamond deposition conditions by adding boron and seeding with diamond prior to deposition, the formation of diamond coatings on carbon fibre composites (CFC) is possible.
Boron doped diamond (BDD) coatings are used in electrochemistry, due to a high overvoltage for oxygen generation. Deposition of BDD on niobium substrates is very common, but also BDD 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.
Electrochemical measurements of the BDD coatings on CFC verified the excellent electrochemical properties of the samples, e.g. good electrical conductivity, high overvoltage for oxygen and hydrogen but also chemical inertness.