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采用热丝化学气相沉积(HFCVD)法,以甲烷和氢气为反应气体,在YG13(WC1-3%Co)硬质合金基体上制备了金刚石膜。膜中存在大量五重对称结构的正二十面体金刚石晶粒(IDC)。当尺寸较小时晶粒为较完整的正二十面体形状,尺寸达微米级后晶粒为带有“沟槽”或“凹坑”的变种正二十面体形状。研究了IDC的形成机制,并进行了计算机模拟。结果表明:对于四面体立方结构来说,IDC的{111}孪晶面与正常{111}孪晶面相比存在2.87o的差异,孪晶面两侧原子几何位置失配,使其成为畸变孪晶面,这种畸变孪晶面导致IDC晶粒存在“凹坑”和“沟槽”;IDC的晶核是正十二面体烷(C20H20)。
A diamond film was prepared on YG13 (WC1-3% Co) cemented carbide substrate by hot filament chemical vapor deposition (HFCVD) with methane and hydrogen as reaction gases. There are a large number of quintic symmetrical structures of icosahedral diamond grains (IDC) in the film. When the size is smaller, the grains are more perfect icosahedron shapes, and the grain sizes up to the micron scale are the regular icosahedron shape with “grooves” or “pits”. The formation mechanism of IDC was studied and the computer simulation was carried out. The results show that for the tetrahedral cubic structure, the {111} twin plane of IDC has a difference of 2.87o compared with the normal {111} twin plane, and the geometric positions of the atoms on both sides of the twin plane are mismatched, making it a distorted twin The crystal plane, the distorted twin planes lead to IDC grains present “pit” and “groove”; IDC nucleus is n-dodecahedron (C20H20).