| 摘要 |
Sintered silicon carbide composites enveloped with diamond or cubic boron nitride (CBN) crystals are made through a process comprising: (a) forming a first and second dispersion of uncoated diamond crystals and carbon black in paraffin; (b) forming a mixture of carbon fiber, carbon black and filler in paraffin; (c) compacting said dispersions and mixture together to produce an integral compact wherein said dispersions form an envelope about said mixture; (d) subjecting said compact to a vacuum for a period of time at a temperature sufficient to vaporize essentially all of said paraffin; (e) heating silicon to cause liquefaction, direct infiltration and diffusion into said compact in vacuum; and (f) sintering the compact containing silicon under conditions sufficient to produce a beta -silicon carbide binder uniting said composite without applying pressure. In preferred composites, the dispersions contain different proportions of diamond or cubic boron nitride crystals. One may be utilized for a peripheral band about the mixture; the other connecting the edge as a surface layer of the composition. These composites are particularly useful as cutting material and/or wear components, where they exhibit extreme wear resistance. |
