Study on the Properties of TiAl-doped DLC Multilayer Coatings Synthesized by Cathodic Arc Evaporation

• Main Authors: J.Y. Jao, 饒瑞昀
• Other Authors: C.L Chang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/37369747305555125544

碩士 === 明道管理學院 === 材料暨系統工程研究所 === 93 === Abstract In this work, the combinations of metal-doped DLC and TiAlN/TiN double-layered films were designed to deposit on the tool steels using cathodic arc evaporation in a single process. The economic advantage in depositing the combined coating in one production scale PVD coating system is of practical importance. The TiAl-doped DLC as lubricant coatings were synthesized with TiAl-target arc sources to emit ion plasma to activate acetylene reactive gases. Experiments were carried out to deposit TiAl-DLC on TiAlN/TiN/M2 tool steel for different substrate bias ranging from -50 to -200 V, hydrocarbon gases (C2H2) pressure 10 to 25 mtorr and temperature fixed at 180 ℃. Scanning electron microscopy (SEM), Auger electron spectroscopy (AES), micro-Raman spectroscopy. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) techniques were employed to analysis the microstructure properties of TiAl-doped DLC coatings. Vicker's and tribometer tester were used to measure the mechanical properties of TiAl-doped DLC coatings. The results indicated that the bias voltage and hydrocarbon gases (C2H2) pressure plays a major role in the microstructure change in the deposition of TiAl-doped DLC films. The profile ID/IG and sp3/sp2 ratio corresponds to the change of microhardness profile as the bias voltage or the hydrocarbon gases (C2H2) pressure varied. And, TiAl metals are in the form of small nanocrystallites of pure metal or metal carbides dispersed throughout the carbon network. The tribo-analysis indicated that the coatings exhibited steady-state friction in the range of 0.15 - 0.25 to the end of 2 km travel distance. Interesting optimum wear rate corresponded to the steady-state low coefficient of friction of DLC films due to formation of graphitized layer. The lubricity and wear resistance of TiAl-doped DLC coatings is then demonstrated to potentially be applied to the cutting tools with no lubricants. To summary, the optimum condition and properties of TiAl-doped DLC coatings was appeared at the bias of-120 V and the hydrocarbon gases (C2H2) pressure of 15 mtorr.