Nanoindentation instruments

Nanoindentation instruments emerged as a consequence of the need to characterize mechanically the surfaces of thin films and near surfaces (within 1000 nm of the surface). The type of instrumentation and data processing needed for nanoindentation is essentially different from the microhardness tester (Pollock, 1992). 

Table 2.2. Commercial nanoindentation instrument specifications. (From Pollock, 1992.)...

The development of multipurpose nanoindentation instruments that also perform scratch testing, profiling, and measurements of scratch hardness, film stress, friction, and other surface-mechanical properties. 

The actual trend in hardness testing is to use the nanoindentation instruments in conjimction with atomic force microscopes (45). Load-displacement measurements are used to derive hardness and elastic modulus data while the atomic force microscope yields additional topographic information of the indentation area. Measurements at depths of 1 nm can be performed. 

In AFM, the relative approach of sample and tip is nonnally stopped after contact is reached. Flowever, the instrument may also be used as a nanoindenter, measuring the penetration deptli of the tip as it is pressed into the surface of the material under test. Infomiation such as the elastic modulus at a given point on the surface may be obtained in tliis way [114], altliough producing enough points to synthesize an elastic modulus image is very time consuming. 

In this chapter, we overview basic techniques for making nanoscale adhesion and mechanical property measurements. Both quasi-static and dynamic measurements are addressed. In Section 2 of this chapter, we overview basic AFM instrumentation and techniques, while depth-sensing nanoindentation is overviewed in Section 3. Section 4 addresses recent advances in instrumentation and techniques... 

Nanoindentations were carried out by using a commercial AFM (AutoProbe CP Research, Park Scientific Instruments) equipped with a commercial capacitance transducer (TriboScope, Hysitron) with a three-sided pyramidal dia-... 

Another modem instrument used for nanoindentation and for nanotribological studies of polymers is the surface force microscope (SFM) (Ovemey, 1995a). 

In situ TEM can be performed to study the optical, electrical, and mechanical properties of materials. The instrumentation involved considers several types of specimen holders. At present, the main types of specimen probes used in industry are electrical probing (TEM-STM) [32], micro-force (TEM-nanoindenter) [33], nano-force (TEM-AEM) [34, 35], optical, scanning fiber, multiple electrical wire. 

Specimens were placed in a holder and loaded to fiacture in a nanoindentation machine with a flat-tipped diamond indenter. Load and displacement were monitored throughout the loading cycle. The instrument was typically operated in load control with a total ramp time to fiacture of about 13 s. 

The nanofiller structure was studied on force-atomic microscope Nano-DST (Pacific Nanotechnology, USA) by a semicontact method in the force modulation regime. The received CNT size and polydispersity analysis was made with the aid of the analytieal disk centrifuge (CPS Instrument, Inc., USA), allowing to determine with high precision the size and distribution by sizes in range from 2 run up to 5 mcm. The nanocomposites BSR/CNT elasticity modulus was determined by nanoindentation method on apparatus Nano-test 600 (Great Britain). 

Experimental techniques most commonly used to probe the plastic properties of thin film materials involve direct tensile loading of either a freestanding film or a film deposited onto a deformable substrate material, microbeam bending of films on substrates, substrate curvature measurement or instrumented depth-sensing nanoindentation. Sahent features of these methods, as well as specific examples of the adaptation of these methods for the study of mechanical properties in thin films, are briefly addressed in the following subsections. 

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