X-ray photoelectron spectroscopy and secondary-ion mass spectrometry of boron nitride thin films on austenitic stainless steel

In order to grow thin films of boron nitride (BN), AISI 316 austenitic stailess steels have been doped with 10 and 50 ppm B and then thermally treated in dissociated NH3. The chemical composition and the distribution of the segregated phases onto the stainless steel surfaces have been studied by means of X-ray photoelectron spectroscopy (XPS) and secondary-ion mass spectrometry (SIMS). XPS depth profiles and SIMS elemental images have shown that boron segregates and reacts with dissociated NH3, thus essentially forming hexagonal BN. In particular, on high-boron-doped material, the hexagonal BN layer almost uniformly covers the surface of the steel, while on low-boron-doped steel the formation of hexagonal BN occurs only at the grain boundaries. For both materials, SIMS images have revealed also the presence at the grain boundaries of complex carbide-nitride-boride species. © 1993.