Diamond Berkovich

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... 

A fully automated microscale indentor known as the Nano Indentor is available from Nano Instmments (257—259). Used with the Berkovich diamond indentor, this system has load and displacement resolutions of 0.3 N and 0.16 nm, respectively. Multiple indentations can be made on one specimen with spatial accuracy of better than 200 nm using a computer controlled sample manipulation table. This allows spatial mapping of mechanical properties. Hardness and elastic modulus are typically measured (259,260) but time-dependent phenomena such as creep and adhesive strength can also be monitored. 

A nano hardness tester (CSEM) with a Berkovich in-denter tip (diamond, radius 100 nm) was used. For all... 

In hardness tests by scratch methods, apart from the previously mentioned diamond cones with included angle of 90° or 120°, trihedral pyramid-shaped points (Bierbaum pyramid and Berkovich pyramid) and Vickers tetrahedral pyramid (Fig. 4.3.3) are now widely used their main... 

With the rapid advances now observed in hardness test methods (Vickers, Knoop, Grodzinski, Berkovich and Hanneman diamond indenters or Brinell and Rockwell hardness testers, etc.), the 10-degree Mohs scale poses a number of problems owing to the low distinction of hardness... 

The standard methods to determine the coating microhardness by indentation of a pyramid-shaped diamond indenter are described in ASTM E384-07 (2007). Depending on the shape of the indenter, Knoop- and Vickers-type diamonds as well as Berkovich indenters can be distinguished. The reported hardness number expressed in N mm-2 (MPa) is the force exerted on the specimen surface by the diamond indenter used to produce the impression. In principle, the technique is less affected by porosity than the scratch tests based on measuring the indenter travel caused by a specific increase in load. Microhardness tests are usually made... 

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.

Pyramid Indenters. The most common pyramid indenters are the Vickers, Knoop, and Berkovich indenters. The Vickers indenter consists of a square-based diamond pyramid with included angles (a) of 136° between nonadjacent faces. The Knoop test uses a rhombic-based diamond with included angles of 172° and 130° between opposite edges. The Berkovich indenter is a diamond trigonal pyramid whose facets form an angle of 65.3° with respect to the normal to the base. 

To assess the scratch behavior of polsmiers, scratch tests are performed. A compendium of the use of various instruments and methods applied is given in Reference (20). Although different setups have been used for scratch studies, the basic principle relies on the use of a stylus to scratch a surface (2,3,21 3). The stylus can be made of materials ranging from diamond and sapphire, to tool steel, and silicon nitrite for the case of AFM tips. It also comes with a variety of geometries including conical tips with different included angles, spherical tips of different radii, and Berkovich tip. In addition, the observation length scale and controlled experimental parameters are instrument specific. 

Berg Method. See diver method. Berkeley Clay. A plastic, refractory kaolin from S. Carolina P.C.E.34. Berkovich Indenter. A 3-faced diamond pyramid for indentation hardness tests. 

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. 

Figure 6b and c shows the dynamic compliance and corresponding phase shift of the indenter (uncorrected for electronics). The response was fit to the model in Fig. 6a for this indenter the damping coefficient, Q is 0.008 Ns/m, resonance frequency, Q)o is 110 Hz, indenter mass, m is 236 mg, and spring constant, Ki is 116 N/m. A Berkovich diamond indenter with a tip radius of -200 nm was used for all experiments. Tip shape calibration and machine compliance were determined by standard techniques (14) using electropolished indium and quartz. 

Barium titanate (BaTi03), strength after indentation, 185 Barrel indents, 44-126 BeBg Knoop hardness, 303 Beevers-Ross sites, 280 Berkovich hardness anisotropy, 94 diamond, 11, 39-40 equation, 11... 

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. 

HaU effect measurement, 467 hardness measurement in sol-gel coatings aluminium alloy, use of, 304 antireflex coatings, 305 Berkovich indenter, 303, 304 defomation mechanisms, 302 diamond indenter, 302 elastic modulus, 303 indentation testing, 302 indium-tin-oxide coatings, 305 loading-unloading cycle, 303 pencil hardness, 305 Poisson s ratio, 303 silica, 304... 

The area-depth function depends on the shape of the indenter used, and there are standard relationships for specific indenters. For example, a Berkovich indenter (typical of a diamond tip indenter in many AFM systems) has A = 24.5hc, while for a spherical indenter, A = Tv(2Rhc + h/), where R is the indenter radius. There are corrections made for the depth, h, to become h to account for the actual contact area because A is less than what would be calculated for h (see Figure 33.1). The following equation finds h. ... 

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