Hardmetal alloys are processed by liquid phase sintering, which consist of one refractory carbide, embebided in to a tough matrix of Co. These alloys extensively are used in applications that demand abrasion resistance and high hardness. The present work has as objective to analyze the sintering of ultrafine powders of tungsten carbide (WC) with the addition of 10%wtCo. The alloys had been prepared by using high pressure and high temperature technique. The sintering of the WC/10%pCo alloy was processed at the 3, 4 and 5 GPa, in temperatures of 1300,1400 and 1500°C, during 2 and 4 minutes. The analysis was made by microstructure, densification, structure, Vickers hardness and fracture toughness. The best results was density = 98.9%, hardness HV30 =10,77GPa and fracture toughness KIC = 15,57 MPa.m1/2.