Influence of the milling parameters on the sintering behaviour of WC-Co composites

ABSTRACT

Often, in the studies dealing with the properties of WC-Co composites, the powders are mixed without quantifying the influence of this operation on the properties of the powders. Generally, WC powder, cobalt powder, and inhibitor powder are mixed together in a ball mill. The mixing time varies from 30 minutes to 72 hours in low-energy mixers or high-energy mills. In these conditions, the homogenization effect on the powder may differ greatly. To study the effect of the homogenization operation on the characteristics of two components, a mixture of WC and 10 wt.% of binder doped with Cr₃C₂ as GGI was prepared. The milling was carried out at speeds of 300 and 600 rpm, using two sizes of ball, for 6 hours. After sintering, the densification was significantly improved for the high-energy processed powders only. Moreover, the results confirm the important influence of mixing parameters on the powder behavior during sintering.

KEYWORDS:

• WC
• GGI
• cobalt
• milling
• duration
• homogenization
• sintering
• properties