SURFACE,STRUCTURE OF INTERFACE AND ADHESION OF DIAMOND FILMS DEPOSITED ON CHROMIZED LAYER OF A STEEL

CVD diamond films were deposited on the chromized layer of a steel. The surface,the structure of interface and the adhesion of the films were investigated using scanning electron microscopy,transmission electron microscopy (TEM) and indention tests. The diamond purity and interfacial phases were evaluated with Raman Spectroscopy. When the CH4∶H2 ratio is higher than 0.6%,diamond film is composed of spherical nanograins,and the nucleus density is larger than 107cm-2. The residual compressive stress on the surface of diamond film synthesized at 0.6% CH4 is 1.22 GPa,lower than that of the film back,2.61 GPa. The film cracks at 19.6 N load in indention tests. TEM observation indicates the film/substrate interface is micro-rough and thus beneficial to adhesion.