SHRINKAGE BEHAVIOR OF WC-CO HARD METALS

The outgassing and sintering behaviour of WC-Co hard metals is investi gated by complex thermal analysis especially in view of shrinkage (dil atometry), mass loss (thermogravimetry), gas evolution (mass spectrome try) and formation of the eutecticum (DSC). Concerning the shrinkage i t is known that solid-state sintering contributes more than 75% toward s the total densification of hard metals and strongly depends on prope rties and processing of the starting powders. A model of that solid-st ate sintering prior to the binder melting is proposed and may be used to understand the processes and basic mechanisms of particle approach and particle rearrangement. Both effects are based on diffusion contro lled creep processes on the surface of the particles.