X-ray absorption studies of the bonding structure of B-C-N compounds

Although cubic BCN compounds are desired for their attractive mechanical properties, the synthesis in thin film form of these compounds normally yields amorphous material containing different local structures like trigonal bonding (hexagonal structure), tegragonal bonding (cubic structure) and formation of B12 icosahedra. X-ray absorption (XANES) spectroscopy is a well suited technique to analyse the local structure of these amorphous coatings and discern between formation of single phase or multiple phase and ternary compounds or mixtures of binary grains. We have synthesized a variety of ternary BCN compounds by using Ion Beam Assisted Deposition (IBAD) techniques using B4C, B and C solid evaporation sources with concurrent ion bombardment from mixtures of N2, Ar and CH4 gases. In this way, hydrogenated and hydrogen-free BCN compounds with various compositions are obtained. The bonding structure of the different compounds is discussed in connection with the sample preparation method.