对几种薄膜硬度测试方法的评定

Evaluation of hardness measurement methods for thin films

用传统的显微硬度计直接测量薄膜硬度难以避免基体的影响且小载荷压入时产生的较小的压痕不易被准确测量。纳米压入仪是一种可以精确控制及测量压入深度的高精度仪器。这种通过测压入深度测硬度值的技术可以减少基体硬度对薄膜测量硬度的影响同时产生的误差较直接测压痕对角线的误差小。但是,纳米压入仪对试样表面光洁度要求高,仪器价格昂贵。这些都限制其在实际工业中的应用。较好的一种硬度测试方法是通过传统显微硬度计在不同的大载荷下测得膜基复合硬度,同时建立适当的模型计算出薄膜的本征硬度值。此方法可能更适合于常规应用。

The conventional Vickers hardness measurement for thin films cannot get rid from the influence of substrate and the resolution of small indentation is also poor. Nanoindentor is a modern instrument, which can provide a precise control and accurate measurement of indentation depth. By controlling the indentation depth, the effect of substrate on film hardness can be eliminated. The measure- ment error of indentation depth is much less than that of indent diagonal. However, nanoindentor requires well prepared surface with low roughness of specimen, and this instrument is expensive, that limits its application in industry. One method studied in this paper may be available for some special cases. The composite hardness of coated specimen can be measured by the conventional Vickers hardness tester with relatively heavy load, then the intrinsic hardness of thin film can be calculated using a proper model. This method would be a suitable way for industrial applications.