Optical, physical and chemical properties of a Diamond-Like Carbon Film and its Wear-Resistant Performance

• Main Authors: Hao Yu Yang, 楊浩宇
• Other Authors: Jen Fin Lin
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/71188320365693478544

碩士 === 國立成功大學 === 機械工程學系 === 87 === The research on Diamond-Like Carbon (DLC) has found the numerous applications in industry but the research is limited. In this thesis, Gridless Ion Beam Source (GIBS) method is used to deposit various thickness DLC on CR39 plastic lens. The effects of two different thickness of intermediate layer and the addition of SiO2 are investigated. The primary topics on this thesis are as follows: 1. The structure and optical properties of DLC are investigated by Raman Spectrum, X ray Diffractometer (XRD), ellipsometer and visible transmission. 2. The wear test under different operating conditions. 3. The evaluation of adhesion strength by tape pull-off test based on ASTM standard. 4. The humidity durability and salt spray test based on MIL standard. This thesis studies on the relationship among these results. From the analysis of DLC microstructure and the pull-off test, the quality of this DLC film is excellent. The microstructure is amorphous and the graphitization is low. On the optical property, the refraction index is 2.0~2.1 in the visible light area and extinction coefficient is 0.13~0.23 and the transitivity is above 60%. With the addition of SiO2, the films tends to cracking and the adhesion strength, the wear resistance and erosion resistance is reduced. This is contrary to the common belief that the addition of SiO2 is advantageous in adhesion and wear resistance. The film thickness seems to play an important role in these areas. The thicker the film, the wear-resistance is better but the transitivity is reduced. However, the thickness of SiO2 is not arbitrary: only certain thickness ratio with DLC films improves the quality of the overall property. The occurrence of cracks in deposition films will greatly reduced the erosion resistance as well as the wear resistance capability. The adhesion strength is crucial in the evaluation of the deposition quality. For low adhesion strength, the erosion resistance reduced accordingly. The correlation with wear resistance is less obvious. In wear test, the average friction coefficient increases as the load increases; however, the average friction coefficient decreases slightly as the rotation speed increases. For thicker DLC film (above 80nm), the applied load and the rotation speed must exceed certain value to initiate the cracking in the films.