Effect of surface oxides and intermetallics on nanostructured diamond coating of nitinol
Effect of surface oxides and intermetallics on nanostructured diamond coating of nitinol
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DOI：
10.2174/157341306775473809
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发表时间：
2006-02-01
影响因子：
1.5
通讯作者：
Vohra, YK
中科院分区：
文献类型：
--
作者：
Catledge, SA;Thomas, V;Vohra, YK
采用微波等离子体化学气相沉积（CVD）技术在机械抛光的超弹性镍钛合金表面生长纳米金刚石。如通过掠射角X射线衍射所确定的，机械抛光的严重氧化的接收样品导致去除镍，Ni 3 Ti和TiO 2表面相，留下待检测的NiTi奥氏体（B2型，CsCl结构）。金刚石成核和生长是不切实际的缓慢的机械抛光的样品，只能产生连续的薄膜在实际的增长率时，他们首先暴露于等离子体退火，以允许形成氧化物和金属间相（Ni 3 Ti，NiTi 2）。表面层（由氧化物和/或金属间相组成）作为碳扩散屏障的能力可能是导致观察到的界面TiC形成增加的原因，从而导致约1 μ m/小时的实际金刚石生长速率。
Microwave plasma chemical vapor deposition (CVD) was used to grow nanostructured diamond onto mechanically polished superelastic Nitinol (NiTi) alloy. As determined by glancing-angle x-ray diffraction, mechanical polishing of the heavily oxidized as-received samples resulted in removal of nickel, Ni3Ti, and TiO2 surface phases, leaving the NiTi austenite (B2 type, CsCl structure) to be detected. Diamond nucleation and growth was impractically slow on the mechanically polished samples and could only yield continuous films at practical growth rates when they were first exposed to plasma annealing to allow formation of oxide and intermetallic phases (Ni3Ti, NiTi2). The ability of a surface layer (composed of oxides and/or the intermetallic phases) to act as a barrier to carbon diffusion may be responsible for an observed increase in interfacial TiC formation leading to practical diamond growth rates of about 1 mu m/hour.