PHASE-FORMATION IN THE N-B-TI SYSTEM

In this work we report some experimental results on the N-B-Ti system. Boron nitride thin films were prepared by rf sputtering and then ion implanted with 200 keV Ti+ ions at various doses. The films were chara cterized by scanning electron microscopy (SEM), glancing incidence X-r ay diffraction (GXRD), secondary neutral mass spectrometry (SNMS) and nano-indentation, both in the as-deposited and ion implanted condition and also after thermal annealing. SEM pictures show the development o f various microstructures as the Ti-dose increases. GXRD shows that Ti B2 is formed at low doses while TiN prevails at high doses. At very hi gh doses, elemental Ti is predominantly observed. Hardness and Young's modulus increase as the Ti dose increases up to saturation values. Ti depth profiles of specimens implanted at various doses show a radiati on enhanced diffusion of Ti at low doses. However the Ti diffusivity i s reduced with the appearance of TiB2 and TiN phases.