Influence of Pulse Bias Voltage on Composition and Structure of Multi-arc Ion Plating TiAlN Thin Films

- Apr 21, 2018-

TiAlN thin films were deposited on high-speed steel substrates by multi arc ion plating. With the increase of the bias peak, the large particles on the surface gradually decrease, the compactness gradually becomes better, and the hardness of the films increases. The deposition parameters have an effect on the composition of the films. The peak value of bias has a significant effect on the Al content in the films, while duty ratio mainly affects the Ti content.

As the first generation of hard film materials, TiN has been widely used in the production of cutting tools because of its high hardness, low friction coefficient and good conductivity and thermal conductivity. However, with the increasing demand for thin-film materials, TiN is unable to meet the requirements of high temperature, high speed cutting, dry cutting tools, dies and other mechanical processing fields because of the poor high temperature oxidation resistance.

TiAlN thin film is a new type of multi-component thin film coating developed on the basis of TiN. The Al element is added to the TiN to form TiAlN film, and the Al element is easy to form alumina at high temperature, which can effectively improve the high temperature oxidation resistance of the film. The TiAlN films have excellent properties such as high hardness, high oxidation temperature, good thermal hardness, strong adhesion, low friction coefficient and low thermal conductivity, etc. Therefore, TiAlN is considered to be a more promising new coating material than TiN and is widely used in various fields.

The TiAlN thin film was deposited by multi-arc ion plating. The effect of pulse bias and duty ratio on the microstructure of TiAlN thin film was investigated. The following conclusions can be drawn:

(1) With the increase of pulse bias and duty ratio, the larger particles on the surface are significantly reduced and the surface morphology is better.

(2) The peak of bias voltage increases and the deposition rate becomes smaller. When the duty ratio is increased, the deposition rate increases first and then decreases. At a duty ratio of 40%, the deposition rate is the maximum.

(3) The atomic percentage of Al is mainly affected by the peak value of the pulse bias and decreases with increasing bias voltage; the atomic percentage of Ti is mainly affected by the duty ratio and decreases with the increase of the duty ratio.

(4) With the increase of the pulse bias, the hardness of the film increases first and then decreases, and with the increase of duty ratio, the hardness of the film increases first and then decreases, and there are obvious changes in the film hardness.