On the Sintering Behavior of Nb2O5 and Ta2O5 Mixed Oxide Powders

Abstract

A mixed oxide system consisting of Nb2O5 and Ta2O5, was subjected to annealing in air/hydrogen up to 950 °C for 1–4 h to study its sintering behavior. The thermogravimetric–differential scanning calorimetry (TGA–DSC) thermograms indicated the formation of multiple endothermic peaks at temperatures higher than 925 °C. Subsequently, a 30% Ta2O5 and 70% Nb2O5 (mol%) pellet resulted in good sintering behavior at both 900 and 950 °C. The scanning electron microscope (SEM) images corroborated these observations with necking and particle coarsening. The sintered pellets contained a 20.4 and 20.8% mixed oxide (Nb4Ta2O15) phase, along with Ta2O5 and Nb2O5, at both 900 and 950 °C, indicating the possibility of the formation of a solid solution phase. In situ high-temperature X-ray diffraction (XRD) scans also confirmed the formation of the ternary oxide phase at 6 and 19.8% at 890 and 950 °C, respectively. The Hume–Rothery rules could explain the good sintering behavior of the Ta2O5 and Nb2O5 mixed oxides. An oxide composition of 30% Ta2O5 and 70% Nb2O5 (mol%) and a sintering temperature of 950 °C appeared adequate for fabricating well-sintered oxide precursors for subsequent electrochemical polarization studies in fused salts.

Powder Metallurgy: Materials and Processing

“…The SI consists of 16 papers (published between 2022 and 2023): a review article [ 1 ], a viewpoint paper [ 2 ], a communication [ 3 ], and thirteen research articles [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. The papers reflect the current trends in the field: the search for new compositions (not investigated previously) of materials and the development of new processing approaches enabling better control and flexibility of the materials’ microstructures, shapes, and architectures.…”

“…The research papers report recent findings in metallic [ 4 , 5 , 6 , 7 , 8 , 9 ], ceramic [ 10 , 11 , 12 ], polymer [ 3 ], and composite materials [ 3 , 13 , 14 , 15 , 16 ].…”

“…Interesting ceramic systems in terms of composition have been investigated in [ 10 , 11 , 12 ]. Bannykh et al [ 10 ] conducted a systematic study of the products of interaction between the W 2 B and iridium powders.…”

“…Bannykh et al [ 10 ] conducted a systematic study of the products of interaction between the W 2 B and iridium powders. Chorney et al [ 11 ] reported the sintering behavior of Nb 2 O 5 and Ta 2 O 5 mixtures and the formation of a ternary oxide. Akopdzhanyan et al [ 12 ] elaborated the synthesis of MgAlON powders via combustion reactions.…”