The Fabrication And Properties Of Titanium Aluminum Nitride Coatings

As one of the physical vapor deposition method, multi-arc plating process can be especially used to prepare metallic compound coatings or metal coatings with high melting point on metal surface. It has been on rushing developed since 1980's and become one of the most advanced plating techniques at present. TiAlN coatings have high hardness. Its performances are better than TiN coatings.TiAlN coatings are deposited by multi-arc plating process on Ti and Ti6A14V alloy. Scanning electron microscopy (SEM), EDAX and X-ray diffraction (XRD) are used to investigate the composition, microstructure, components and phases of coatings. Film-substrate hardness ratio of the system is measured with auto micro-hardness tester. Bond strength of film-substrates is measured by scratch tests. Skimming wear and inching wear mechanics are also investigated. The effect of bias voltage on TiAlN microstructure and properties were studied. The results show that TiAlN coatings have been made in different parameters by varying bias voltage. Droplets density was reduced while holes density was increased with the bias voltage rising. Varying bias voltage has little effects on composition of TiAlN coatings. Both bias voltage and substrate lead to preferred orientations much more different in phases of coatings. At bias voltage of -600V and -450V, the coatings on Ti6A14V alloy have higher (110) preferred orientation, while at bias voltage of -100V, the coatings on Ti6A14V alloy have higher (106) and (102) preferred orientation. All of the coatings on Ti have higher (110) preferred orientations. The micro-hardness of TiAlN coatings is HV1935. Film-substrate hardness ratio of the system has been accounted. The result shows that at bias voltage of -450V, the coatings and Ti6A14V alloy have better capability of coordinate deformation while coatings and Ti have better capability of coordinate deformation at bias voltage of-100V. TiAlN coatings and substrates bond strengths are measured by scratch test. At bias voltage of—450V, the coatings on Ti6A14V alloy have better bond strength and the critical load L_c is 56.25N while coatings on Ti surface have better bond strength at -100V bias voltage and the critical load L_c is 62.5N. Wear test showed that the friction coefficient and the wear volume of TiAIN coatings are lower than those of Ti6A14V alloy and Ti. Thus the wear resistance of TiAIN coatings was significantly better than substrates.