Growth of Super-Tough Nanocomposite Films by Hot-Filament Chemical Vapor Deposition

• Main Authors: Wen-han Fang, 方文翰
• Other Authors: Franklin Chau-Nan Hong
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/76352444786464888490

碩士 === 國立成功大學 === 化學工程學系碩博士班 === 96 === Diamond films are of significant interest for tribological applications because of their high hardness, chemical inertness, low friction coefficient and high wear resistance. But diamonds are brittle with low fracture toughness. This flaw limits the use of diamonds for applications in harsh environments of dynamic impacts and high stress concentrations. We can fabricate nanodiamond-SiC or nanodiamond-TiC composite films by hot-filament chemical vapor deposition. We expect that the ideas are designed by microstructure to satisfy the mechanisms of strength and toughness. And it can raise the hardness and toughness of nanodiamond films. We fabricate nanodiamond-SiC composite films in the most optimized conditions. Compare with nanodiamond films, the hardness enhances from 63.8GPa to 78.5GPa. The enhancement scope achieves 23%. We measure the toughness by Vickers. We change the applied loading (500~10000mN) to observe the behavior about the fracture of the films. The nanodiamond films fracture when the applied loading is 1000mN. But the nanodiamond-SiC composite films don’t fracture when the applied loading is over 10000mN. The toughness of composite films can raise substantially because add the solute atoms to nanodiamond. It can inhibit the cracks expand rapidly and avoid fracture. And it also changes the nature of brittle fracture.