Synthesis of Heavy Tungsten Alloy by Thermal Technique

Abstract

Heavy tungsten alloy with composition 93W:3Ni:2Fe:2Co was successfully prepared through gaseous reduction technique. Starting from tungsten, nickel, iron, and cobalt oxides, a mixture of these oxide powders was reduced by treatment in hydrogen. The course of reduction was followed up by measuring the weight loss as a function of time in the temperature range of 850–1000 °C. Afterward, samples were subjected to sintering process in reducing atmosphere (Ar/4% H2) at different temperatures (1300–1500 °C) and dwell times (30, 90 min) to investigate the microstructural changes occurring during sintering. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the reduced samples. The microhardness of the sintered samples was measured and correlated to sintering temperature and dwell time. It was found that the heavy tungsten alloy can be synthesized from metal oxide at reduction temperatures above 850 °C. The reduction rate increased with temperature. The values of the apparent...