US Patent 7422513 Porous abrasive articles with agglomerated abrasives

A bonded abrasive tool, having a structure permeable to fluid flow, comprises sintered agglomerates of a plurality of abrasive grains and a binding material, the binding material being characterized by a melting temperature between 500 and 1400° C., and the sintered agglomerates having a loose packing density of ≦1.6 g/cc and three-dimensional shape; a bond material; and about 35-80 volume % total porosity, including at least 30 volume % interconnected porosity. Methods for making the sintered agglomerates and abrasive tools containing the sintered agglomerates are described.