Development of Thick TiN Film on Aluminum Substrate and Its Wear Properties
Takao HANABUSA, Tadakazu MORIGUCHI, Kazuya KUSAKA, Tatsuya MATSUE
Abstract:In the industrial fields, aluminum (A1050) and aluminum alloys (A5052 and A2017) are widely used in mechanical components. However, their application is essentially restricted because of their low strength and low hardness. In the present study, TiN film deposition was tried on a surface of aluminum and aluminum alloy substrates by means of an arc ion plating. The aim is to develop thick TiN film on aluminum based materials in order to get strong wear resistance. In order to minimize an increase of the substrate temperature throughout the deposition, the process was planned to deposit TiN intermittently with cooling intervals of 120 min. Arc current, bias voltage and coating time were changed to examine their roles on hardness and wear property of TiN films. X-ray diffraction study revealed (100) preferred orientation in the film deposited under the condition of low bias voltages, whereas (111) under high bias voltages. No cracks were observed in the films deposited on the A5052 and A2017 substrates under the bias voltage below -30V, however, they occurred in the films deposited higher than -20V on A1050 substrate. Low bias voltage should be essential to obtain thick TiN films on aluminum-base materials. Wear test was made by a ball-on-disk type machine. The depth of wear traces observed in the films with the thickness of 9 lm on A1050 substrate was about 40 lm. However, no wear traces appeared in the other films deposited under low bias voltages; regardless of film thickness. Although the hardness of the film was reduced with using low bias voltage, the wear property was greatly improved by thick TiN coatings. Key Words:TiN film, Aluminum substrate, Arc ion plating, Wear property, Crystal orientation, X-ray diffraction