(TI1-XALX)N COATINGS BY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

(Ti1-xAlx)N was deposited on high-speed steel using a radio-frequency (rf) plasma-enhanced chemical vapor deposition (PECVD) process from the gas mixture of TiCl4, AlC13, NH3, H-2, and Ar. The composition of the coated layer could be controlled from TiN to (Ti0.17Al0.83)N by the ratio of source gases, TiCl4 and AlCl3. At the same ratio of AlCl3 and TiCl4, the Al content in die coated layer was changed by die rf power employed. According to x-ray diffraction and transmission electron microscopy, the PECVD-(Ti1-xAlx)N coating with x less-than-or-equal-to 0.77 was found to have a NaCl-type structure with Ti atoms substituted by Al atoms and a strong crystallographic texture of (200), but (Ti0.17Al0.83)N had a mixed phase of TiN + AlN. it was also found that the hardness, the adhesion, and the surface morphology of the coated layer were affected by the Al content as well as by the rf power employed.