Activity of W-Powder-A Controlling Parameter for Interconnected Porosity of Sintered Porous W-Bodies

摘要

For many performant applications aften are necessary W-bodies with precisely controlled interconnected porosity and in the same time with good mechanical strength, which are two opposite material features. A high mechanical strength demands the utilization of a W-powder with a good sinterability (activity), that is a very fine one. But such a W-powder tends to form closed porosity. To avoid the appearence of closed porosity and to assure concomitantly a maximum quota of total porosity interconnected porosity as were conducted experiments with coarser W-powder (less than 45 μm), that was activated before pressing and sintering by a mechanical treatment with different durations. To enhance the sintering in addition 0,5 w/o Ni was added to W-powder. The effect of mechanical treatment duration on the mechanical strength was determined by compression tests. SEM porosity studies on the fracture surface of compression testing specimens were also made.