Quantification of Oxide Inclusions and Porosity Structure in a Tantalum Carbide Microstructure Fabricated From Carbothermal Reduced Tantalum Oxide Precursor Powders

The oxide inclusion and porosity defect structures in a tantalum carbide specimen fabricated from vacuum plasma spraying with postspraying sintering and hot‐isostatic pressing has been characterized. The tantalum carbide powders were obtained using a carbothermal reduction process of tantalum oxide precursors. During its fabrication, oxide‐based inclusions formed from intrinsic impurities in the powder. Using serial sectioning and three‐dimensional reconstruction techniques, interconnected globular oxide inclusions were revealed to be within the matrix phase and in the grain boundaries. The oxide phase was identified to be z ‐Ta 2 O 5 through selected area electron diffraction. The two‐ and three‐dimensional porosity size distribution was compared and accounted for ~2% of the volume.