INDEX microhardness

One of the most popular techniques used for determining the hardness of a material is the Mohs scale that consists of a qualitative but an arbitrary hardness index scheme ranging from extremely soft materials (value of 1 Moh) to very hard materials such as diamond (10 Moh). Other techniques that are often employed for measuring hardness of substances are developed by Rockwell [72], Brinell [72], Knoop, and Vickers [73]. Over the years, more quantitative methods such as nanoindentation [74] have been developed. This technique applies a small and a controllable load on to the substrate with a probe. The depth of penetration along with a known geometry of the probe provides an indirect way to measure the area of contact at full penetration, which is then used to determine the hardness. The hardness is determined by the ratio of the total force to the contact area. Table 7.2 lists the bulk hardness of different materials, metal films, and abrasive particles, in both Moh and microhardness scales [75]. 

Glass type Transparency range (p-m) Refractive index d Abbe value Vd Thermal expansion a (10"Vk) Microhardness HV Transformation temperature TgCC) Density e (g/cm )... 

Si-0 asymmetric stretching vibration, microhardness, density, and refractive index of multicomponent borosilicate gels after heat treatments between room temperature and 600°C (heating rates = 0.5-2,0 C/min) (175). 

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