Abstract Synthetic diamond films have attracted great attention for their extreme properties and potential engineering applications as protective and wear-resistant coating for cutting tools. Nanocrystalline diamond (NCD) coatings were synthesized from CH4/H2/Ar (1/10/89%) microwave plasma at four deposition temperatures (TD) ranging from 653 to 884 °C. The hardness (H) and Young's modulus (E) of NCD coatings measured at three different loads (10, 25 and 47 mN) depended on the nanoindentation load-level. The NCD coating produced at the lowest TD showed values of H = 121 ± 25 GPa and E = 1036 ± 163 GPa at the highest load. This result was attributed to the formation of elongated nanocrystallites at low deposition temperature. Further, the NCD coating obtained at lower deposition temperature exhibited an anomalous indentation size effect (ISE), i.e. a reverse ISE (RISE), which was ascribed to the heterogeneity of grain sizes along the [220] and [111] directions. Finally, a positive and negative (inverse) Hall-Petch behavior was observed for grain sizes along the [111] and [220] directions, respectively.

中文翻译：

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纳米晶金刚石涂层的负载敏感超硬度

摘要 合成金刚石薄膜因其优异的性能和潜在的工程应用而备受关注，作为刀具的保护和耐磨涂层。纳米晶金刚石 (NCD) 涂层是由 CH4/H2/Ar (1/10/89%) 微波等离子体在 653 至 884 °C 的四个沉积温度 (TD) 下合成的。在三种不同载荷（10、25 和 47 mN）下测量的 NCD 涂层的硬度 (H) 和杨氏模量 (E) 取决于纳米压痕载荷水平。在最低 TD 下生产的 NCD 涂层在最高负载下显示出 H = 121 ± 25 GPa 和 E = 1036 ± 163 GPa 的值。该结果归因于在低沉积温度下形成细长的纳米微晶。此外，在较低沉积温度下获得的 NCD 涂层表现出异常压痕尺寸效应 (ISE)，即反向 ISE (RISE)，这归因于沿 [220] 和 [111] 方向的晶粒尺寸的不均匀性。最后，分别观察到沿 [111] 和 [220] 方向的晶粒尺寸的正负（逆）霍尔-佩奇行为。