| 摘要 |
Metal- or ceramic-bonded ultra-hard boron nitride composite material production, by hot pressing a mixture of fine matrix powder and boron nitride particles in the presence of a pulsed heating current, is new. Metal- or ceramic-bonded composite materials, containing dispersed ultra-hard boron nitride, are produced from a matrix material and binder powder, which has a fine particle or crystal size for high sintering activity or which (partially) melts during sintering, by (a) dispersing, mixing and grinding the powder with boron nitride in a liquid medium to achieve homogeneous mixing and particle deagglomeration, followed by drying; and (b) densifying the dry powder mixture to a low porosity body by application of pressure and heat in the presence of a pulsed heating current. An Independent claim is also included for a composite material produced by the above process and having a relative porosity of less than 10%, the material comprising 1-65 (preferably 35-45) vol.% boron nitride and either (i) 20-80 (preferably 40-60) vol.% matrix consisting of one or more of Ti, Al, Si, W, Ta, Zr, V, Hf, Cr, B, N, C and O in elemental, compound, alloy, crystalline or amorphous form and 4-60 (preferably 5-15) vol.% binder (partially) enclosing the matrix and cubic boron nitride (CBN) particles or (ii) 20-99 (preferably 50-70) vol.% matrix consisting of one or more of Ti, Al, Si, W, Ta, Zr, V, Cr, Y, Sc, rare earths, B, N, C and O in elemental, compound, alloy, crystalline or amorphous form surrounding the boron nitride particles and 0-30 vol.% oxides, oxynitrides or oxycarbonitrides.
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