| Summary: | 碩士 === 國立虎尾科技大學 === 機械與電腦輔助工程系碩士班 === 102 === AlCrSiTiVN multicomponent thin films were prepared on silicon and tungsten carbide samples using a cathodic arc deposition system. Ti60V40 and Cr60Al30Si10 cathodes were used for the deposition of AlCrSiTiV multicomponent thin films. By controlling the Ti60V40 and Cr60Al30Si10 cathode current ratio, the microstructure and composition of the AlCrSiTiVN coatings were changed. For the high temperature oxidation analyses, annealing of the deposited AlCrSiTiVN coatings at 500°C and 700°C in air were conducted.
The microstructure of the AlCrSiTiV multicomponent thin films were characterized by using a field emission scanning electron microscope (FE-SEM), high resolution transmission electron microscope(HRTEM), and an X-Ray diffraction(XRD) instrument. The chemical composition and bonding structures of the oxidized coatings were identified by electron spectroscope for chemical analysis, (ESCA). Mechanical properties including adhesion ,hardness and Young''s modulus were measured by using a Rockwell indentation testerand a nanoindenter. A dynamic impact fatigue test was used to evaluate the impact fatigue performacne of the deposited AlCrSiTiV thin films.
The results showed that the AlCrSiTiVN-1 film with equal caothde currents of Ti60V40 and Cr60Al30Si10 cathodes had the highest hardness of 33 GPa due to the smallest grain size 13.2nm . The hardness increased with decreasing grain size down to a critical value 10–20 nm. The results of room temperature impact test showed that AlCrSiTiVN-1 film possessed the best impact resistant due to its high hardness and fracture toughness. At 500˚C, the impact test results also showed that AlCrSiTiVN-1 film still had good resistance to impact fatigue because vanadium oxide were formed to provide lubricity at high temperature. From the XRD analyses, AlCrSiTiVN films had fcc-NaCl structure, vanadium pentoxide (V2O5 ) were formed after annealing at 500˚C. AlCrSiTiVN-0.5 film with the highest Al contents had the best thermal oxidation resistance. Al2O3、VO2、AlVO4 and V2O5 were formed after annealing at 700˚C. The 700 ˚C impact test results showed that AlCrSiTiVN-0.5 film had the best impact resistantance.
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