Enhanced wear resistance in steel by recoil implantation and ion vapour deposition of aluminium films

The wear resistance of medium carbon steel has been enhanced by up to 10 times by 84 keV N + implantation of thin aluminium films deposited onto the steel surface. The implantation was performed after (recoil implantation) or during (ion vapour deposition) thermal deposition of aluminium films 30–150 nm thick. The wear resistance of these samples was better than that for unirradiated hardened high carbon steel samples. Low energy ion scattering and X-ray diffraction were used to identify the mechanisms responsible for the improvements seen during tungsten carbide ball-on-disc wear testing. Nitrogen implantation of aluminium layers 53 nm thick produced the lowest wear rate on the steel and the WC ball. This improvement is due to the formation of a surface iron-rich layer supported by hard iron and aluminium nitrides well bonded to the substrate.