Deposition of (Ti, Al)N films by filtered cathodic vacuum arc

(Ti, Al)N films were deposited by a new off-plane double bend filtered cathodic vacuum arc technique under a nitrogen atmosphere. The substrates were held at ambient temperatures during the deposition of (Ti, Al)N films. Atomic force microscopy and X-ray diffraction were used to characterize the structure of the films. The internal stress, micro-hardness and Young's modulus were also studied. All (Ti, Al)N films deposited were atomic smooth. The surface roughness increases with increasing nitrogen pressure. The crystal structure, internal stress and mechanical properties of (Ti, Al)N films are strongly dependent on the nitrogen partial pressure. At lower nitrogen pressure, the structure of (Ti, Al)N films is composed of (Ti, Al)N phase, metal-rich nitride phase and metallic phase. The deposited films show (111) preferred orientation growth. With increasing nitrogen pressure, the structure change to single fcc type (Ti, Al)N phase, and a mixed (111) and (220) orientation was observed. Further increase of nitrogen pressure causes the disappearance of (Ti, Al)N phase and the formation of porous films. The hardness and Young's modulus of (Ti, Al)N films increase to a maximum at the pressure of 1.98×10^-1 Pa, then decrease with increasing nitrogen pressure. The variation trend of internal stress in the films with nitrogen pressure is the same as that of hardness.