Boron carbide (boron carbide)

Japanese: 炭化ホウ素(炭化硼素) - たんかほうそ

Boron carbides are said to exist with compositions ranging from BC to B ₆ C, but the most certain one is B ₄ C, which is usually called boron carbide. Its specific gravity is 2.51, its melting point is 2450°C, and its Knoop hardness is about 2800. In industry, it is made by heating boron oxide (B ₂ O ₃₎ and carbon to 2500-2600°C. Because of its high hardness, its powder is used for wrapping high-hardness ceramics and as an abrasive for ultrasonic processing. Because it has poor oxidation resistance, it is rarely used in the form of a grinding wheel (grinding stone).

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

ホウ素の炭化物には，BCからB₆Cまでの組成のものが存在するとされているが，最も確実なものはB₄Cで，ふつうこれを炭化ホウ素と呼んでいる。比重は2.51，融点2450℃，ヌープ硬さは約2800。工業的には酸化ホウ素B₂O₃と炭素とを2500～2600℃に熱してつくる。硬度が高いため，粉体は高硬度セラミックスのラッピングや超音波加工の砥粒に用いる。耐酸化性に乏しいため，研削といし(砥石)の形にして使うことはほとんどない。

出典　株式会社平凡社世界大百科事典第２版について　情報

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