Development of high density tungsten based scandate by Spark Plasma Sintering for the application in microwave tube devices

Abstract

In this work, an attempt has been made to synthesize Scandate material which is basically a composite of tungsten (W) with mixed oxides of Sc, Ba, Ca, and Al in powder form prepared by high energy planetary ball mill (PBM) and subsequently making of sintered pellet by Spark Plasma Sintering (SPS). The nano sized Sc2O3 has been evidenced through XRD and TEM, which indicates the particle size in between 10 and 50nm. The nano crystallite nature of BaCaAl2O3 has been found from FE-SEM with particle size <50nm with stable phase of Ba7Al2O10 through XRD analysis, formed during the calcination of BaCaAl2O3 at 1100°C. The quantitative analysis of Scandate pellet was confirmed by Electron Probe Micro Analyzer (EPMA) which shows the maximum percentage of W resides in most of region along with other constituent elements of Scandate materials. X-ray Micro Computed tomography study of Scandate Pellet revealed the homogenous distribution of W matrix throughout across the 3D geometry with absence of pores signifying dense sample. The mixture composite of the said matrix after making pellet with the help of SPS was found to be ≈99% density.