Mechanical hardness

If Ihe main incoming male contacts are made ol aluminium alloy, which is normally a eompnsilioii of aluminium-magnesium and silicon, they must be provided wiili a coat of bron/e. copper and tin to give it an adequate mechanical hardness and resistance to corrosion. For more details refer to Section 27.2..5. 

FIG. 37. Internal stress and mechanical hardness as functions of nitrogen content, and for films deposited from aC2H2-N2 mixture. (Reproduced from [56].)... 

Chemistry and Physics of Mechanical Hardness, by John J. Gilman Copyright 2009 John Wiley Sons, Inc. 

In dielectric materials (oxides, semiconductors, halides, polymers, and he like), polarizability correlates with hardness. For metals, this is not the case. However, the frequencies of the collective polarizations known as plasmons are related to mechanical hardness. 

Yang, Parr, and Uytterhoeven (1987) have shown that chemical and mechanical hardnesses (physical stabilities) are connected. Consider the isotropic case, and differentiate Equation 16.5 with respect to N ... 

Chemistry and physics of mechanical hardness / John J. Gilman. 

For the structural applications of materials, there is no more useful measurable property than mechanical hardness. It quickly and conveniently probes the strengths of materials at various scales of aggregation. Firstly, it does this at the human scale (Brinell hardness—millimeters to centimeters). Secondly, it does so at a microscopic scale (Vickers microhardness—1 to 100 microns). And thirdly, it does so at a nanoscale (nanoindentation—10 to 1000 nanometers). 

Hardness does not produce a complete characterization of the strengths of materials, but it does sort them in a general way, so it is very useful for quality control for the development of new materials and for developing prototypes of devices and processes. Furthermore, mechanical hardness is closely related to chemical hardness, which is a measure of chemical bond stability (reactivity). In the case of metals the connection is somewhat indirect, but nevertheless exists. 

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