Forming From Powders

Abstract

The considerations for powders are the particle size, which affects the resulting properties, and the particle size distribution, which affects the packing density. Smaller-particle-size compositions have higher strengths because they have more surface area, and therefore more bonds, than those with larger particles. Increased packing densities can be achieved by mixed sizing with coarse and fine grains. The porosity can be minimized, with the finer grains filling the interstitial vacancies between the larger grains. The ideal mixture is approximately 70 percent coarse grain and 30 percent fine grain.