LASER-CHEMICAL VAPOR-DEPOSITION OF TIN AND TIC FILMS

Laser chemical vapour deposition (LCVD) of TiN and TiC films has been achieved by scanning linear deposition in a dynamic atmosphere on AISI 52100 bearing steel using TiCl4, NH3, C2H4 and H-2 as reactant gases induced by CO2 laser. It has been found in our experiment that hydroge n played an important role in the LCVD TIN process. LCVD TiN film is g olden in colour, single phase, stoichiometric in composition and homog eneously distributed. Preferential orientation of LCVD TIN film is cor related with deposition pressure. The microstructure of LCVD TiN film comprises about 2 mu m equiaxial particles, each particle consisting o f about 15 nm nanocrystalline grains. The average Knoop microhardness of LCVD TiN films is HK 1400 and the highest is HK 1602.3. The wear re sistance of LCVD TIN film is four times that of the substrate. LCVD Ti C film, with no preferential orientation, comprises homogeneous stoich iometric single-phase equiaxial particles.