Synthesis of multifunctional microdiamonds on stainless steel substrates by chemical vapor deposition

Abstract

We report on the synthesis of multifunctional microdiamonds by chemical vapor deposition (CVD) on 304 and 316 austenitic stainless steel (SS) substrates. The increase in wettability achieved by surface scratching and the structure of ultra-dense Q-carbon achieved high nucleation density and minimized strains in diamond films. Notably, these diamond films exhibit a high amount of twinning, leading to the formation of five-fold microdiamonds. The diamonds on scratched SS substrate and Q-carbon interlayer exhibit a full width at half maximum of 8.25 cm−1 and 11.5 cm−1, compared to 26 cm−1 on bare SS substrate. The diamond films grown on bare SS substrate exhibited cracking due to high tensile stress of 2.3 GPa, ascribed to thermal mismatch between SS and diamond. The electron backscattered diffraction investigations reveal iron inclusions in diamonds synthesized on bare SS substrates, which may create ferromagnetism in these diamonds. This route, compared to the ion beam implantation method using ferromagnetic ions, yields better samples. At 800 °C, 1012 Fe atoms/cm2s are transferred from the SS substrate into the diamonds. The dominant growth orientation for these CVD diamonds was determined to be <110> out of plane. These multifunctional microdiamonds are useful for biomedical, electronic, and tribological applications.