US Patent 7074247 Method of making a composite abrasive compact

There is provided a method of making a composite abrasive compact which comprises an abrasive compact bonded to a substrate. The abrasive compact will generally be a diamond compact and the substrate will generally be a cemented carbide substrate. The composite abrasive compact is made under known conditions of elevated temperature and pressure suitable for producing abrasive compacts. The method is characterised by the mass of abrasive particles from which the abrasive compact is made. This mass has three regions which are: (i) an inner region, adjacent the surface of the substrate on which the mass is provided, containing particles having at least four different average particle sizes; (ii) an outer region containing particles having at least three different average particle sizes; and (iii) an intermediate region between the first and second regions.