Modern materials are subject to elaborate testing regiments, and nanoindentation and nanotribology are technologies that can help address this. For bulk materials like metal alloys there are long-established test methods for hardness and indentation; however, these methods are not suitable for many materials due to the tiny scale of the samples. As products become miniaturized and coatings become thinner, materials scientists have had to adapt their instrumentation to the nanoscale.

Consequently, a small industry has sprung up to facilitate the nanomechanical testing of materials. The most common type of such testing is nanoindentation, which is primarily used to measure the hardness, modulus of elasticity and creep of materials. The measurement is relatively straightforward, albeit not necessarily simple to achieve at the nanoscale. Nanoindenters function by pushing an indenter made of hard material, such as diamond or sapphire, onto the sample with a prearranged force and time profile. In addition to the force, the displacement of the tip into the sample is carefully measured, either through direct imaging or electromechanical measurements. Software can convert these raw measurements into the various mechanical properties and moduli.

In addition to basic indentation, many other potential measurements can be made. The science of tribology relates to friction and rubbing, and at the nanoscale, surface treatments and coatings can have powerful effects on surface roughness and friction. Consequently, nanotribology has been developed to provide useful measurements for evaluating materials. In addition to measuring the static and dynamic friction of surfaces, systems can be used to measure wear by moving the probe in contact with the surface back and forth over a number of cycles to determine the resistance of the sample to repetitive stresses.

Another mode of analysis commonly used with nanoindentation and nanotribology systems is microscopy. The general setup of these instruments is fairly similar to AFM, and thus AFM capabilities are commonly found with these systems. Optical microscopy is also a relatively frequent addition to these systems to provide a visual inspection of indentations, wear and scratch tests. Some systems are also designed for inclusion within the sample chamber of electron microscopes or FIB systems, providing high-resolution microscopy and other sample preparation possibilities.

Although these systems can be applied to the same kind of bulk samples as their grander-scale brethren, the main utility is for samples that cannot be tested with larger-sized instrumentation. A common example is thin layers placed over a substrate, where the interest is the mechanical properties of the thin layer. Larger instruments would penetrate into the substrate, where the nanoindenter only scratches the surface. Common sample types include paints, elastic coatings, thin films, polymers, fused silica for optics, ceramics, and even soft materials like gels or biological specimens. Tribological applications are similar, but there are more opportunities to study lubricants and lubrication, as well as the opposite, namely adhesives and adhesion properties.

Bruker, which acquired Hysitron in 2017 (see IBO 1/30/17), is the leader in the nanoidentation and nanotribology market, offering a wide variety of solutions for standalone analysis, process systems and systems geared for use within electron microscopes. Bruker’s other businesses in AFM and Raman imaging also enable the a variety of possible hybrid systems. Keysight Technologies (formerly part of Agilent Technologies) had been one of the primary vendors of nanoindentation products, but in April, the company’s nanoindentation product lines were acquired by KLA-Tencor (see IBO 8/15/18). Prior to the acquisition, KLA-Tencor already had an existing business for a specialized system, the Nanoflip, for use inside electron microscopes. The third largest vendor is Fischer Technology, which is a quite specialized firm for the inspection and analysis of coatings and other nanoscale features. A number of other market participants exist, including Anton Paar, Micro Materials, Nanovea, Oxford Instruments, Zwick and Optics 11, the last of which is notable for focusing primarily on biomaterials.

Leading Vendors:

• Bruker
• KLA-Tencor
• Fischer Technology

Largest Markets:

• Coatings
• Polymers
• Metals

Instrument Cost:

• $25,000–$750,000