Direct solid state synthesis of W-Al_2O_3 nanostructured composite using ammonium paratungstate (APT) and Al powder mixture

摘要

W-Al_2O_3 nanostructured composite has been produced by mechanical milling of ammonium paratungstate (APT) and Al powder mixture at room temperature. The milled products have been characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). The XRD and EDS results confirmed that direct reduction of APT to α-W took place after 25 min milling. It was observed that α —> β phase transition took place after 24 h mechanical milling. SEM micrographs showed that alumina matrix composite reinforced with W could be obtained by one step MSR (mechanically induced self-propagation reaction) process. X-ray diffraction peak broadening equation confirmed that the mean grain size of these particles was in nanometer range which gradually decreased with increasing the milling time.