The preparation of fine carbide powders from coal solutions
- CSIR, Pretoria (South Africa)
Non-oxide ceramics, such as silicon carbide, find use in applications requiring extreme hardness, chemical inertness and high-temperature strength. Transition metal carbides, such as tungsten carbides cemented with cobalt or nickel, are used extensively as wear components. Articles are generally fabricated by sintering pressed powder bodies at high temperatures. To maximize strength and hardness of the ceramic bodies, fine powders below 1 micron in size are needed together with small additions of sintering aids. Boron carbide plus carbon are used as sintering aids for silicon carbide. Very uniform dispersion of the sinter aid or binder metal with the carbide powder is necessary. This is achieved by milling the components together, often for many hours. The carbides are generally prepared by reacting the metal or oxide together with carbon. The low reactivity of particulate carbon means that high temperatures have to be used with extensive milling being required to reduce the particles to a suitable size. The end result of these requirements is that sinterable powders are expensive.
- OSTI ID:
- 420478
- Report Number(s):
- CONF-950402--
- Journal Information:
- Preprints of Papers, American Chemical Society, Division of Fuel Chemistry, Journal Name: Preprints of Papers, American Chemical Society, Division of Fuel Chemistry Journal Issue: 2 Vol. 40; ISSN ACFPAI; ISSN 0569-3772
- Country of Publication:
- United States
- Language:
- English
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