金刚石涂层硬质合金是一种出众的刀具材料，将碳化硅掺入金刚石涂层中不仅可以提高涂层的断裂韧性，还能够提高薄膜与基体之间的粘附性。文章采用氢气、甲烷和四甲基硅烷混合气体作为反应气体，用直流等离子体辅助热丝化学气相沉积法在硬质合金基体上沉积金刚石-碳化硅-硅化钴复合薄膜。通过扫描电子显微镜、电子探针显微分析、X 射线衍射和拉曼光谱对薄膜的表面形貌、成分以及结构进行了分析，结果显示此复合薄膜中含有金刚石、碳化硅(β-SiC)和硅化钴(Co2Si、CoSi)。复合薄膜的结构和成分可通过调节偏流和气相中四甲基硅烷的浓度来控制，随着偏流的增加，复合薄膜中金刚石晶粒尺寸变大且含量增加，β-SiC 的含量减少，因为复合薄膜沉积过程中正偏压促进金刚石的生长，并且增强金刚石的二次形核。虽然电子轰击同时增强了氢气、甲烷和四甲基硅烷的分解，但随着偏流的增加，气相中产生的碳源浓度高于硅源浓度，使金刚石比β-SiC 在空间生长上更具有优势。当偏流过高时则形成纯金刚石，不能够同时沉积金刚石、β-SiC 和硅化钴三种物质。通过调节偏压和气体成分，金刚石和碳化硅在复合薄膜中的分布得以控制。该工作有助于理解和控制复合材料和超硬薄膜的生长，所产生的复合薄膜可用于提高金刚石涂层刀具切削性能。%Diamond coated hard metal is an outstanding cutting material for manufacturing. By adding SiC to the diamond coating material, not only the surface toughness but also the film adhesive strength can be improved. Diamond/β-SiC/cobalt silicide composite films were deposited on Co-cemented tungsten carbide (WC-Co) substrates by direct current plasma assisted hot iflament chemical vapor deposition using a gas mixture of hydrogen, methane and tetramethylsilane. Scanning electron microscopy, electron probe microanalysis, X-ray diffraction and Raman scattering analyses were carried out to characterize the surface morphology, composition and structure of the deposited iflms. The results revealed that the composite iflms consist of diamond,β-SiC and cobalt silicides (Co2Si, CoSi). The structure and composition of the composite films can be controlled by adjusting bias current and tetramethylsilane concentration in the gas phase. With the increase of bias current, the grain size and content of diamond also increase, while the content ofβ-SiC decrease. Since bias current enhances the secondary nucleation and growth of diamond. Although the dissociation of hydrogen, methane and tetramethylsilane are all enhanced by electron bombardment during the biasing process, the concentration of produced C sources is much higher than that of Si sources with the increase of bias current. Then the growth of diamond becomes more competitive than that ofβ-SiC. The bias current cannot be too high to deposit the three substances of diamond,β-SiC and cobalt silicides. By adjusting bias and gas composition, the distribution of diamond and β-SiC in the composite films was manipulated. These results demonstrated the signiifcance to understand and control the growth of composite materials and super hard thin iflms. Such composite iflms can be utilized to improve the cutting performance of diamond coated cutting tools.
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