| 摘要 |
A refractory dispersion comprises Fe, Co or Ni or an alloy of one or more of these with the optional addition of up to 30% of one or more conventional alloying elements (e.g. Cr, Mo or W) and has dispersed therein 1 to 99 part by volume of one or more nitrides of Ti, Al, Nb, V, Zr, Ta or Wf per part by volume of the metallic component and a refractory aluminium compound having a melting point above 1200 DEG C. and a heat of formation greater than 10 Cals per gram atom of aluminium at 298 degrees Kelvin (e.g. alumina or aluminium nitride). Both the essential nitride and the refractory compound must comprise at least 5% by volume of the non-metallic component. The essential nitride may be partially replaced by one or more of the nitrides of Be, Mg, B, U, Ce or Th, the carbides of Ti, W, Zr, Mo, Cr, Ta or Nb, the oxides of Ti, Zr, Mg or Th or the borides of Ti or Zr but the minimum amount of the essential nitrides must still be 5% by volume of the non-metallic component. The compositions are made by conventional powder metallurgical processes.
|
