The effect of deposition temperature and boron addition in Ti-B-C-N films deposited by plasma-enhanced chemical vapor deposition

Quaternary Ti-B-C-N films were synthesized on AISI 304 stainless steel and Si wafer by a PECVD technique using a gaseous mixture of TiC14, BCl3, CH4, Ar, NZ, and HZ. The microstructure and micro-hardness of the films were largely affected by the deposition temperature and boron content. As the temperature increased from 370 degrees C, the micro-hardness of the film steeply increased due to the enhanced crystallinity of the film and reached to the maximum value of 42 GPa at 570 degrees C. However, the hardness decreased again at higher temperatures above 570 degrees C due to the enlarged grain size. The boron addition into Ti-C-N film resulted in the microstructural modification and our quaternary Ti-B(9 at.%)-C-N film had a fine composite microstructure consisting of nano-sized Ti(C,N) crystallites surrounded by amorphous phase of BN. The micro-hardness of Ti-B-C-N film increased from similar to 21 GPa of Ti-C-N film up to -42 GPa of Ti-B(9 at.%)-C-N one. In this work, a systematic investigation of the microstructure and micro-hardness of Ti-B-C-N films were conducted at the deposition conditions of various temperatures and boron contents through the instrumental analyses. (c) 2007 Elsevier B.V. All rights reserved.