Influence of cobalt on the attritor milling efficiency of WC-Co powder blends

Abstract

This work investigates the effect of Co content on the energy-specific WC surface area relationship in attritor milling for slurries in which a constant 22 vol % solids is maintained. It is shown that increases in the Co level result in decreased milling efficiency, although the effect is less pronounced than might be anticipated, particularly at the highest Co concentrations (up to 24 wt %). Comparisons to a recent study on attritor milled WC-Co blends in which a constant 85 wt % solids (22–26 vol %) was maintained show that increased vol % solids also results in decreased milling efficiency. Increases in the Co level and/or the extent of grinding are shown to cause an increase in the apparent viscosity of the slurry. Changes in the vol % solids of the slurry are demonstrated to have an exponential effect on the apparent viscosity. It is expected that the vol % solids will have a dominant effect on viscosity for concentrations greater than about 24 vol %.