Mechanical and tribological aspects on a-C films deposited by lamp assisted chemical vapour deposition

A novel approach to deposit amorphous carbon films (a-C) from the precursor CH2I2 at low cost and high efficiency is reported. The radiation of a halo gen lamp was used to heat and to photo-dissociate the CH2I2 (g) precursor a s well as the substrate surface. The combination of thermal and photolytic effects shows new interesting growth behaviour. Cemented carbide and Si wer e used as substrates. The films were investigated with respect to hardness and elastic modulus by nanoindention. A ball-on-disc tribometer was used to evaluate the friction and wear of the films in sliding contact against bea ring steel. The adhesion between the film and substrate was :investigated b y Rockwell C indentation. The films were additionally analysed with scannin g electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Raman s pectroscopy. The films showed extremely low surface roughness (R-a < 0.7 nm ) and were free from micro-voids. The hardness and elasticity was measured to 10 and 70 GPa, respectively. Low friction coefficients in the 0.15-regio n were measured. No influence of the substrate material on the film propert ies was found. (C) 2001 Elsevier Science B.V. All rights reserved.