Composite WC–35% Ni Produced from Ultrafine WC + NiО Powders.
I. Density and Structure

Abstract

The density and structure of ultrafine-grained WC–35 wt.% Ni composite produced by short-term solid-state pressing at different temperatures and at pressure ∼ 1200 МPа are examined. The initial powder mixture consists of tungsten carbide and nickel oxide, but one part of the mixture is reduced in hydrogen and the other is mixed with saccharose to reduce nickel from its oxide during heating of green briquettes. In the latter case, it takes one stage to synthesize the metal phase and consolidate the WC–Ni mixture. It is established that the composite samples produced from the powder mixture containing saccharose show more intensive shrinkage during heating than the samples produced from the mixture preliminary treated with hydrogen. High pressure permits obtaining practically porousless samples above 1150 °С. It is shown that the structure of the composite obtained from the carbide–oxide mixture by reduction of saccharose carbon is more fine-grained and differs by more uniform distribution of tungsten carbide in the nickel binder.