Effect of nitrogen partial pressure on characteristic and mechanical properties of hard coating TiAlN Film

C Chokwatvikul, S Larpkiattaworn, S Surinphong, C Busabok, P Termsuksawad

Abstract


(Ti,Al)N coating has been serving for the industry as cutting and forming tools. Compared with TiN film, TiAlN film significantly increases tool lifetime. Therefore, it reduces machine downtime and increases productivity. In this work, (Ti,Al)N film was deposited on cold-work tool steel (SKD 11) using PVD cathodic arc system. The sintered Ti-Al target with composition of (at%) 50 Ti and 50 Al was used as a cathode. The deposition bias voltage, bias arc current and deposition time were set at 100 V, 70 A and 90 minutes, respectively. Nitrogen gas was purged into the system with the applied pressure of 1, 1.5 and 2 Pa, respectively. After coating, the film was characterized for crystal structures and mechanical properties. It was found that all films have the same crystal structures of Ti0.5Al0.5N and TiN0.5 with the thickness in the range of 2-3 ?m. Moreover, the film prepared at N2 pressure of 1.5 Pa possesses the highest hardness (48 GPa), high adhesion strength (>150 N), and good adhesion (HF1 class). The difference of hardness and adhesion of the film was found to be resulted by size and dispersion of macroparticles.

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Printed ISSN: 0857-6149

Online ISSN: 2630-0508