Continuously deposited duplex biomedical coatings

Research has been carried out on a diamond-like-carbon (DLC) coating using different methods over the last few years. It was found that this coating exhibited low friction, high hardness, high resistance to wear and corrosion, along with good biomedical properties, which are desirable for orthopedic implants. However in many cases, due to the very thin nature of the DLC coatings, the soft substrate carries the applied load, which can lead to catastrophic premature failure of the thin film when subjected to high-applied load, through the collapse of the layer on the plastically deformed soft substrate. It was also found that inadequate adhesion to the soft substrates due to the generation of high residual stress in the film as it grows on the surfaces. s paper, continuous duplex process consisting of low temperature (∼ 420 °C) plasma nitriding followed by in situ deposition of the DLC coating is reported. This is achieved by using PECVD based saddle field neutral fast atom beam source. The amorphous and diamond nature of the deposited coating was confirmed by XRD, Raman and FTIR analysis. The microhardness result showed that the duplex treatment significantly increased the composite hardness and reduced the plastic deformation of the substrate. An improvement in the adhesion in the duplex treated sample compared to the non-duplex treated sample was confirmed by the Rockwell C indentation test. The pin-on-disk test result exhibited that the duplex treatment increased the overall wear properties of the coating compared to the non-duplex coating.