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The refractory metals show a wide variety of chemical properties because they are members of three distinct groups in the periodic table. They are easily oxidized, but this reaction is slowed down in the bulk metal by the formation of stable oxide layers on the surface (passivation). Especially the oxide of rhenium is more volatile than the ...
Refractory materials are classified into three types based on fusion temperature (melting point). Normal refractories have a fusion temperature of 1580–1780 °C (e.g. fire clay) High refractories have a fusion temperature of 1780–2000 °C (e.g. chromite) Super refractories have a fusion temperature of > 2000 °C (e.g. zirconia)
Its thermal conductivity (2,200 W/m•K) is five times greater than the most conductive metal (Ag at 429); 300 times higher than the least conductive metal (Pu at 6.74); and nearly 4,000 times that of water (0.58) and 100,000 times that of air (0.0224). This high thermal conductivity is used by jewelers and gemologists to separate diamonds from ...
Nonmetals show more variability in their properties than do metals. [1] Metalloids are included here since they behave predominately as chemically weak nonmetals.. Physically, they nearly all exist as diatomic or monatomic gases, or polyatomic solids having more substantial (open-packed) forms and relatively small atomic radii, unlike metals, which are nearly all solid and close-packed, and ...
In metallurgy, non-ferrous metals are metals or alloys that do not contain iron (allotropes of iron, ferrite, and so on) in appreciable amounts.. Generally more costly than ferrous metals, non-ferrous metals are used because of desirable properties such as low weight (e.g. aluminium), higher conductivity (e.g. copper), [1] non-magnetic properties or resistance to corrosion (e.g. zinc). [2]
It reacts with moist air to form a thin layer of carbonate that prevents further corrosion. [61] Cadmium is a soft, ductile metal (MH 2.0) that undergoes substantial deformation, under load, at room temperature. [62] Like zinc, it has a crystalline structure (BCN 6+6) that is slightly distorted from the ideal.
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In neutral solution containing oxygen, the metal does not corrode but may corrode in an acidic solution containing oxygen and oxidant. The representative metals are Pd, Ir, etc. Group 5: completely thermodynamically stable metal: E° > 1.23V In all metals, Au is the most resistant to corrosion and does not corrode even in an acid solution with ...