Berkovich nanoindentations

Lichinchi, M., Lenardi, C., Haupt, J., Vitali, R., 1998. Simulation of Berkovich nanoindentation experiments on thin films using finite element method. Thin Solid Films 312, 240—248. 

In recent years there has been much interest in the application of polymer materials at the micro- and nanoscale as microelectronic devices are made smaller and smaller. Constantinides describes an analysis and experiments of materials at the nanoscale. An instrumented pendulum device with a diamond Berkovich indenter was used to indent polymer specimens at a rate of 0.7-1.5 mm/s. The highest impact velocity (1.5 mm/s) corresponded to an impulse energy of 250 nJ. (The Berkovich nanoindenter similar to the Vickers type is normally used for testing the hardness of a material. It has a three-sided pyramid shape. It has also... 

Fig. 29—Scanning elecron micrograph of a smaii nanoindentation made with a Berkovich indenter in a 500 nm aiuminum fiim deposited on giass (from Ref. [64]).

The mechanical behavior of coatings under point loading conditions was studied by nanoindentation using Berkovich indenter on Nano Indenter-II (MTS Systems Corporation, Oak Ridge, TN, USA). The nanohardness of chromium and molybdenum coatings was determined by the Oliver and Pharr analysis. 

The unloading was conducted with the same rate as loading. In the given experiment the Berkovich indentor was used with the angle at the top of 65.3° and rounding radius of 200 nm. Indentations were carried out in the checked load regime with preload of 0.001 mN. For elasticity modulus calculation the obtained result in the experiment by nanoindentation course dependences of load on indentation depth (strain) in 10 points for each sample at loads of 0.01, 0.02, 0.03, 0.05, 0.10, 0.50, 1.0, and 2.0 mN were processed according to Oliver-Pharr method [18]. 

Fig. 26. The SEM image of a typical nanoindentation in Ge (Berkovich tip 70 mN loading (111) surface) revealing plastically extruded material.

In Fig. 6.10, the scheme of volume of the deformed at nanoindentation material calculation in case of Berkovich indentor using is adduced and in Fig. 6.11, the dependence in logarithmic coordinates was... 

FIGURE 6.10 The schematic images of Berkovich indentor and nanoindentation process. 

The nanoindentation experiments were conducted at room temperature with a Nano Indenter XP system (MTS Nanoinstruments, Knoxville, TN) using a Berkovich-type diamond tip. Before each test, the system was calibrated using a fused silica. The continuous stiffness mode (CSM) was used in the tests. Thirty randomly selected different fiber and CVI matrix locations were indented for each component of C/C composites. The method of Oliver and Pharr was employed for the elastic modulus calculations. ... 

The elastic moduli of the as-sintered porous LSCF cathode film samples were measured using a NanoTest nanoindentation platform (Micromaterials, UK) with a spherical diamond indenter tip of 50pm diameter. Compared with sharp indenters like Berkovich tips, benefits of using spherical tips include less sensitivity to surface condition. At least 20 measurements were conducted in different locations for each sample in order to measure the variability of the mechanical response of the sample. Prior to nanoindentation tests, the NanoTest platform was precisely calibrated using a standard sihca sample to establish the system frame compliance. 

Figure 6.2 Schematic diagram of a nanoindentation test (a) and commonly used indenter type (b) Vickers indenter (c) elongated diamond-shaped indent formed on the sample by Knoop indenter (d) spherical indenter and (e) Berkovich indenter.

A Berkovich diamond tip with a total included angle of 142.3° and a radius of around 150 nm was used for the nanoindentation measurements [1-2]. Indentation load-displacement curves were obtained by applying loads ranging from 1 pN to 1 mN. The hardness and reduced elastic modulus of the tribofilms were determined with Oliver s method [35,36], where fused silica with a Young s modulus of 69.7 GPa was used as a standard sample for tip-shape calibration to determine the function of the contact area with respect to the contact depth in a range of 1.5-50 nm. Figure 9.5 shows indentation load-displacement curves obtained for the MoDTC/ZDDP and ZDDP tribofilms at a maximum load of 600 pN and in situ AFM images of the residual indent. A plastic pileup was clearly observed around the indent on both the MoDTC/ZDDP and ZDDP tribofilms. 

In Fig. 10 the scheme of volume of the deformed at nanoindentation material calculation in case of Berkovich indentor using is adduced and in Fig. 11 the dependence yiffde) logarithmic coordinates was shown. As it follows from the data of Fig. 11, the density fluctuation growth is observed at the deformed material volume increase. The ploty(ln extrapolation to y=0 gives In or F )=4.42 10 nm. Having determined the... 

A Nanoindenter II with a blunt Berkovich tip (tip end radius 250 nm at the time of making the experiments) was used for testing the NbN coated samples and the CNx coated samples at loads in the complete range. Due to the fact that the... 

Figure 9. Nanoindentation of a commercial polycarbonate surface using a Berkovich diamond indenter (40 nm radius).

Figure 10. Nanoindentation of a commercial polycarbonate coated with a 2 im thick Vitrinite (trademark of Metroline Surfaces, Inc.) Protective Coating surface using a Berkovich diamond indenter (40 nm radius).

The determination of mechanical properties of periodically re-crystallized Pt thin films has been performed using a nanoindentation test. The sample surface was subjected to a loading — unloading cycle with a Berkovich diamond tip. Using the calculation method developed by Oliver and Pharr,local measurements of both hardness H) and Young modulus E) of the thin Pt films have been carried out. 

Characterization of the mechanical properties of these thin silica layers, unreinforced or reinforced, is usually conducted by using the nanoindentation technique [33-37] to determine the hardness (H) of the layer and the elastic modulus ( ) using the Oliver-Pharr method [38]. In these tests, a Berkovich indenter is used and low maximum loads are applied (in the range of mN) to avoid the influence of the mechanical response of the substrate. A complete review of how to calculate different key mechanical parameters ( , H, fracture toughness, residual stresses, and adhesion) of thin sol-gel coatings using nanoindentation tests and scratch testing with nanoindenter equipment can be found in the work of Malzbender et al. [39]. 

Figure 39.9 Nanoindentation tests in CNT-reinforced siiica coatings (a) ioad-dispiacement curve with discontinuities marked and (b) imprint observed by AFM with cracks observed in the tips of the Berkovich prism (arrows). (Reproduced from Ref. [24].)...

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