Nanoindentation

What is nanoindentation?

Nanoindentation is a process by which mechanical properties, such as elastic modulus and hardness, are measured. It can also provide information on a material's stiffness, fracture toughness, delamination, tensile strength, and stress relaxation. Nanoindentation can be used to monitor these properties on a wide range of sample sizes, including very small components and specific areas of larger samples. The method is widely used in mechanical engineering and product development.

Nanoindentation covers several different kinds of methods: quasi-static, dynamic, and continuous stiffness measurements. The traditional testing method consists of a simple quasi-static load indentation. Load and depth of indentation are measured and the sample material's mechanical properties are calculated. Dynamic nanoindentation uses oscillating load variation to extract the properties of the tested material. Continuous stiffness measurement (CSM) is a combination of static and dynamic loads during indentation. This allows the measurement of depth-dependent properties quickly and efficiently.

How does nanoindentation work?

In nanoindentation, a very small probe tip made of a hard material, usually a diamond, is used to indent the surface of a sample. The system measures the load applied to the tip as well as the depth of indentation during the process. Over time, the force applied to the probe and the distance it moves to the surface are measured.

Nanoindentation and atomic force microscopy

Atomic force microscopes can conduct similar analyses to nanoindentation measurements, as long as the sample material is softer than the AFM tip. The probe is traced over the surface and its positional data is recorded along with the topographic measurements of the sample surface. This can then be used to produce an image of the surface on a tiny scale, allowing it to be further analyzed. Most modern nanoindentation instruments can be directly coupled with AFM analysis to reach the most efficient and precise measurements.

Applications

Nanoindentation is used in several fields of science and engineering to characterize materials including electronics, packaging materials, biological samples, construction materials, and polymers. More precisely, nanoindentation is typically used for thin films, alloys, soft tissues, coatings, and composites. The method finds particular use in modern technology, where components are becoming increasingly smaller. Nanoindentation is an excellent way to analyze these structures and provides valuable information on their physical properties.

Sample requirements and preparation

In principle, nanoindentation requires no sample preparation. However, loose samples and objects can generally not be placed in the nanoindenter. If the sample is loose, it can be super-glued to an AFM specimen disk, glass slide, or wafer. The roughness of the sample surface affects the measured mechanical properties. For this reason, the roughness of the sample surface should be large enough compared to the area of the tip.

Limitations of nanoindentation

Depending on the material characteristics, “pile-up” or “sink-in” of the sample material can cause problems in indentation depth calculations. For this reason, measurements on either very soft or very rough surfaces can be challenging or even impossible.

Need an analysis?

Measurlabs offers high-quality nanoindentation analyses with fast results and affordable prices. You can request a quote through the form below or at info@measurlabs.com. Our experts will get back to you within one business day.