CO-SPUTTERED FILMS WITHIN THE QUASI-BINARY SYSTEM TIN-TIB2

Ti-B-N films with a gradient in the chemical composition were deposite d onto austenitic stainless steel and molybdenum sheets by means of un balanced de magnetron co-sputtering using a separated TiN/TiB2 target. Different energetic contributions necessary for film growth were inve stigated adjusting suitable deposition parameters. Film microstructure was characterized by means of scanning (SEM) and transmission electro n microscopy (TEM), X-ray diffraction (XRD), as well as glancing angle X-ray diffraction (GAXRD) and electron probe microanalysis (EPMA). Co ating hardness was measured using a depth sensing nanoindenter. The mi crostructure of the films appears featureless using SEM fracture cross sections. The grain size determined from TEM investigations ranged be tween 3 and 5 nm. The composition of the films was found to lie on the quasi-binary section TiN-TiB2 within the ternary system Ti-B-N. Coati ngs consisted of nanocrystalline fee and hcp Ti-B-N phases. Microstruc ture as well as chemical composition of the films do not seem to be in fluenced by varying the deposition parameters used in this investigati on. Contrarily, the hardness was strongly influenced by varying the io n bombardment. Hardness values exceeding 50 GPa were obtained for Ti-B -N films. (C) 1997 Elsevier Science S.A.