Effect of tungsten disilicide addition on tungsten boride based composites produced by milling-assisted pressureless sintering

Abstract

In this study, tungsten boride (WB and W2B) based composites with various amounts oftungsten disilicide (WSi2) addition were fabricated by using a combined method of mechanicalmilling (MM), cold isostatic pressing (CIP) and pressureless sintering (PS). MMwas conducted for 4 h in ethanol (wet milling) and Argon atmosphere (dry milling) using ahigh-energy ball mill. WSi2 was used with different amounts (0, 5, 10 and 20 wt.%) in orderto investigate its effect on the resultant products. MM’d powders were compacted usingCIP under a pressure of 450 MPa, and were consecutively sintered at 1600 °C for 2 h and1770 °C for 2 h under Ar atmosphere. Compositional, physical and microstructural characterizationsof the samples were performed using stereo and optical microscopes, X-raydiffractometer, TOPAS software, scanning electron microscope coupled with an energy-dispersivespectrometer, particle size analyzer and gas pycnometer. Sintered products werealso characterized in terms of Archimedes density and Vickers microhardness. Moreover,the oxidation studies of the samples were performed at 500 and 1000 °C via thermogravimetricanalyzer. The results showed that the highest density, microhardness and oxidationstability values amongst the fabricated composites were obtained for the dry milled andsintered WB-20 wt.% WSi2 sample.