Dipartimento di Ingegneria Industriale e Scienze Matematiche, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
Micron. 2012 Feb;43(2-3):215-22. doi: 10.1016/j.micron.2011.07.016. Epub 2011 Aug 12.
Nanoindentation has become a common technique for measuring the hardness and elastic-plastic properties of materials, including coatings and thin films. In recent years, different nanoindenter instruments have been commercialised and used for this purpose. Each instrument is equipped with its own analysis software for the derivation of the hardness and reduced Young's modulus from the raw data. These data are mostly analysed through the Oliver and Pharr method. In all cases, the calibration of compliance and area function is mandatory. The present work illustrates and describes a calibration procedure and an approach to raw data analysis carried out for six different nanoindentation instruments through several round-robin experiments. Three different indenters were used, Berkovich, cube corner, spherical, and three standardised reference samples were chosen, hard fused quartz, soft polycarbonate, and sapphire. It was clearly shown that the use of these common procedures consistently limited the hardness and reduced the Young's modulus data spread compared to the same measurements performed using instrument-specific procedures. The following recommendations for nanoindentation calibration must be followed: (a) use only sharp indenters, (b) set an upper cut-off value for the penetration depth below which measurements must be considered unreliable, (c) perform nanoindentation measurements with limited thermal drift, (d) ensure that the load-displacement curves are as smooth as possible, (e) perform stiffness measurements specific to each instrument/indenter couple, (f) use Fq and Sa as calibration reference samples for stiffness and area function determination, (g) use a function, rather than a single value, for the stiffness and (h) adopt a unique protocol and software for raw data analysis in order to limit the data spread related to the instruments (i.e. the level of drift or noise, defects of a given probe) and to make the H and E(r) data intercomparable.
纳米压痕技术已成为测量材料（包括涂层和薄膜）硬度和弹塑性的常用技术。近年来，不同的纳米压痕仪已商业化并用于此目的。每种仪器都配备了自己的分析软件，用于从原始数据中得出硬度和降低的杨氏模量。这些数据主要通过 Oliver 和 Pharr 方法进行分析。在所有情况下，都必须对柔量和面积函数进行校准。本工作通过多次轮次实验，说明了和描述了用于六种不同纳米压痕仪的校准程序和原始数据分析方法。使用了三种不同的压头，即 Berkovich、立方角和球形，选择了三种标准化参考样品，即硬熔融石英、软聚碳酸酯和蓝宝石。结果清楚地表明，与使用特定于仪器的程序进行的相同测量相比，使用这些常见程序一致地限制了硬度并降低了降低的杨氏模量数据的分散度。纳米压痕校准必须遵循以下建议：（a）仅使用锋利的压头，（b）设定一个穿透深度的上限值，低于该值的测量必须被认为是不可靠的，（c）进行纳米压痕测量时，热漂移要有限，（d）确保载荷-位移曲线尽可能平滑，（e）针对每个仪器/压头对进行特定的刚度测量，（f）使用 Fq 和 Sa 作为校准参考样品，以确定刚度和面积函数，（g）使用函数而不是单个值来确定刚度，（h）采用独特的协议和软件进行原始数据分析，以限制与仪器相关的数据分散度（即漂移或噪声水平，给定探头的缺陷），并使 H 和 E(r)数据可比较。
