Parameters optimization in the planetary ball milling of nanostructured tungsten carbide/cobalt powder

Abstract

In this paper, ball milling parameters: weight ratio of ball to powder, size of milling balls, type of medium, volume of milling medium and rotation speed in the planetary ball milling of nanostructured WC–Co powder were optimized by Taguchi method. WC grain size, median particle size (D50) and specific surface area (SSA) were used to assess the effect of the ball milling. It was found that using ethanol and a balls size combination of 12 + 18 mm could improve the reduction of WC grain size. While using distilled water and a balls size combination of 10 + 12 mm could accelerate the particle size reduction. By an analysis of variance (ANOVA) on the SSA results, it was found that except the weight ratio of ball to powder, all other factors are very significant, and the volume of ball milling medium and the rotation speed offer the largest and the second largest contributions in the SSA reduction. By 10 h of ball milling with the optimized milling parameters, D50 and WC grain size of the ball milled WC–Co powder were about 400 nm and 10 nm, respectively.