| Summary: | 碩士 === 崑山科技大學 === 機械工程研究所 === 96 === Along with the rapid development of industries of liquid crystal display(LCD), micro-electro-mechanical system(MEMS), and thin film solar cell, the processes of nano thin film become more and more important.
However, the micro properties are not the same as macro properties, and then it must use new measuring method to obtain the micro properties. Therefore, the thin film mechanical properties under micro/nano scale are very important.
In this study, the thin film properties are investigated and with different properties coating on different substrate are selected and the relationships between micro/nano wear behavior. We use the micro/nano thin film property measuring machine (NanoTest) with the Pin-On-Disc(POD) mode to obtain the coefficient of friction as change the applied load. And then the scanning electron microscopy was employed to observing the width of wear scar. And the mechanism behavior of micro/nano wear on the thin film surface was analyzed.
The experimental results showing that the metal materials (Ag, Al, Cu and Ti) are coated on the PMMA substrate and the applied load is 1 mN, due to the rough peak contacted, leading to the coefficient of friction is increaseing. When the applied load is 200mN, the ploughing is formed due to the thin film pressed and causes the coefficient of friction is increaseing. The stick-slip phenomenon are formed obviously for Ag thin film morphology, and it was found crack and separated that Al, Cu and Ti coating on the PMMA substrate.
The influence of metal materials of Ti and Cu coating on glass substrate are discussed. When the applied load beyond 100 mN of Ti coating on soft substrate (PMMA), the thin film are separated from substrate due to the shear stress. On the other hand, the Ti coating on hard substrate (glass and Si wafer) and load the 1 mN, the micro-welding are formed because the surface affected by adhesion stress, and the stick-slip phenomenon are formed due to the shear stress leading to slide. Furthermore, when the applied load is 100 mN, the surface is not crack when the trace on the thin film surface. Because of hard material on the part of the substrate, and causes the coefficient of friction decreased. As the experimental results in present study, the relationship of micro wear morphology between thin film and substrate can be obtained, and comprehend the mechanisms of micro/nano wear behavior availably.
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