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lwglwg木虫 (职业作家)
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[求助]
求助:HfB2的熔化热是多少?
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| 求助:HfB2的熔化热是多少?请给出出处哈,急需,感谢! |
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lwglwg
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4楼2007-12-10 15:52:08
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Subcategory: Boride Key Words: HfB2, Boron Material Notes: Gray hexagonal crystals Physical Properties Metric English Comments Density 10.5 g/cc 0.379 lb/in2 Molecular Weight 200.11 g/mol 200.11 g/mol Thermal Properties Melting Point 3100 0C 5610 ?F Descriptive Properties CAS Number 12007-23-7 Color Gray Crystal Structure Hexagonal Heat capacities of HfB2.035 and HfC0.968 from 5 to 350 K hafnium diboride Hafnium diboride is an ultra-high temperature ceramic. It has a melting temperature of about 3250 degrees Celsius. It is an unusual ceramic, having relatively high thermal and electrical conductivities. It is a grey, metallic looking material. Hafnium diboride has a hexagonal crystal structure, a molar mass of 200.11 grams per mole, and a density of 10.5 grams per cubic centimeter. Hafnium diboride is often combined with carbon, boron, silicon, silicon carbide, and/or nickel to improve the consolidation of the hafnium diboride powder (sintering). It is commonly formed into a solid by a process called hot pressing, where the powders are pressed together using both heat and pressure. The material has potential for use in hypervelocity reentry vehicles such as ICBM heat shields or aerodynamic leading-edges, due to its strength and thermal properties. Unlike polymer and composite material, HfB2 can be formed into aerodynamic shapes that will not ablate during reentry. This inorganic compound-related article is a stub. You can help Wikipedia by expanding it. This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer) |
2楼2007-12-08 10:12:13
lwglwg
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3楼2007-12-08 10:41:38
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