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【答案】应助回帖
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hour219: 金币+35, 翻译EPI+1, ★★★★★最佳答案 2012-08-04 11:38:16
In the high temperature oxidation and corrosion environment, no other normal metals can stand high temperature and complex environment like noble metal. Amongst the noble metals, Ir, Rh, and Ru have stronger tensile strength and high-temp break strength than Pt and Pd (especially in 2200C Ir has stronger rupture strength and creep break strength than Pt-Rh alloy). However, the development and application of noble metal Ir, Rh, Ru and their alloy are restricted by relatively low normal-temp plastic, worse high-temp oxidation resistance, high density, high oxidation evaporation velocity, limited resources, and high cost.
Platinum-based high-temp structure material has the following properties: (1) high melting temperature, (2) good oxidation resistance and thermal stability in 900C or higher atmosphere, (3) good corrosion resistance so it can stand serious corrosion of nitric acid, hydrogen cyanide, hydrofluoric acid, up to 1600C melting glass, and other silicate melts, (4) good high-temp strength property and stable mechanical property, (5) good ductility and machinability property to be produced to required structure parts and products, (6) good weldable property to be welded to required parts. Besides the features above, relatively abundant resources and reasonable price make platinum material important in contemporary industry, defense technology, and advanced techniques. |
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