Copper greater strength than monocrystalline forms. The softness of copper partly explains its high electrical conductivity (59.6×10 S/m) and high thermal conductivity, second highest (second only to silver) among pure metals at room temperature. This is because the resistivity to electron transport in metals at room temperature originates primarily from scattering of electrons on thermal vibrations of the lattice, which are relatively weak in a soft metal. The maximum permissible current density of copper in open air is approximately 3.1×10 A/m of cross-sectional area, above which it begins to heat excessively. Copper is one of a few metallic elements with a
Thermal conductivity which converts from specific thermal conductivity to absolute thermal conductivity: Again, since thermal conductivity and resistivity are reciprocals of each other, it follows that the equation to convert specific thermal conductivity to absolute thermal resistance is: The thermal conductivity of T-Global L37-3F thermal conductive pad is given as 1.4 W/(mK). Looking at the datasheet and assuming a thickness of 0.3 mm (0.0003 m) and a surface area large enough to cover the back of a TO-220 package (approx. 14.33 mm x 9.96 mm [0.01433 m x 0.00996 m]), the absolute thermal resistance of this size and type of thermal pad