Composition And Performance Optimization Of The Multi-componient Nitrides Hard Reaction Films

In this paper, the hard reactive films of TiAlNbN are deposited on the basis ofTiAlN film by adding niobium and the properties are investigated by the aid of differentdeposition processes.With the alloy targets of Ti-50Al(at%) and Ti-25Nb(at%), the composite hard filmsof TiAlNbN and the gradient hard films of TiAlNbN are deposited on high speed steelsubstrates by multi arc ion plating (MAIP) technology. The surface morphology,cross-section morphology, surface composition and phase structure of the two kinds offilms are measured and characterized. The hardness of the films, the adhesive forcebetween the film and the substrate, the friction and wear properties and the thermal shockresistance at650℃are tested and analyzed.The results show that the surfaces of the two kinds of films are uniform and denseand with the increase of bias voltage, the number of droplets decreases. The number ofdroplets on the surface of the composite hard films of TiAlNbN is lower than the numberon the surface of the gradient hard one. Under the same process, the number of dropletson the surface of the two kinds of films is obviously less than the ones on the surface ofTiAlN films and it greatly improves the surface morphology of TiAlNbN films. Thethickness of the two kinds of films is about1.3~1.8um and there are no obviously defectsbetween the film and substrate. The films have the columnar crystal organization ofvertical growing from the substrate to the surface and with the increase of bias voltage,the thickness has a certain decrease. The main phase structures of the two kinds of filmsare both of TiN phase face-centered cubic structure of B1-NaCl style. The preferredorientations of TiAlNbN films are both of (111) face.The highest hardness of the composite hard films of TiAlNbN can achieve to3000HV and the adhesive force between the film and the substrate is100N~110N.However, the values of the gradient hard films of TiAlNbN are3500HV and more than200N respectively. The hardness and the adhesive force of the two kinds of films are bothsuperior to the TiAlN one.The friction coefficients of the two kinds of films are both lower than0.5. Under the same process, the wearing loss of the radius of5mm is obviously larger than the2.5mmone and with the increase of bias voltage, the wearing loss decrease and the frictioncoefficient is stable.In thermal shock resistance, the number of composite hard films of TiAlNbN is9~10while the gradient hard one is11~14. Both the films are failure with the generationof microcrack and the thermal shock resistance of the gradient hard films of TiAlNbN ismuch better than the composite hard one. In the meantime, under the process of thegradient films, the thermal shock resistance of TiAlNbN films is superior to the TiAlNfilms.