On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide Powders
A mixed oxide system consisting of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5,</sub> 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 (...
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2022-07-01
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| Online Access: | https://www.mdpi.com/1996-1944/15/14/5036 |
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| author | Maureen P. Chorney Kunal Mondal Jerome P. Downey Prabhat K. Tripathy |
| author_facet | Maureen P. Chorney Kunal Mondal Jerome P. Downey Prabhat K. Tripathy |
| author_sort | Maureen P. Chorney |
| collection | DOAJ |
| description | A mixed oxide system consisting of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5,</sub> 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% Ta<sub>2</sub>O<sub>5</sub> and 70% Nb<sub>2</sub>O<sub>5</sub> (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 (Nb<sub>4</sub>Ta<sub>2</sub>O<sub>15</sub>) phase, along with Ta<sub>2</sub>O<sub>5</sub> and Nb<sub>2</sub>O<sub>5</sub>, 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 Ta<sub>2</sub>O<sub>5</sub> and Nb<sub>2</sub>O<sub>5</sub> mixed oxides. An oxide composition of 30% Ta<sub>2</sub>O<sub>5</sub> and 70% Nb<sub>2</sub>O<sub>5</sub> (mol%) and a sintering temperature of 950 °C appeared adequate for fabricating well-sintered oxide precursors for subsequent electrochemical polarization studies in fused salts. |
| first_indexed | 2024-03-09T06:17:21Z |
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| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-09T06:17:21Z |
| publishDate | 2022-07-01 |
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| spelling | doaj.art-f83ff7e05db74e55aa4db27c952df61a2023-12-03T11:52:56ZengMDPI AGMaterials1996-19442022-07-011514503610.3390/ma15145036On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide PowdersMaureen P. Chorney0Kunal Mondal1Jerome P. Downey2Prabhat K. Tripathy3Department of Materials Science and Engineering, Montana Technological University, Butte, MT 59701, USAMaterials Science and Engineering Department, Energy and Environment Science and Technology Directorate, Idaho National Laboratory, Idaho Falls, ID 83415, USADepartment of Materials Science and Engineering, Montana Technological University, Butte, MT 59701, USAPyrochemistry & Molten Salt Systems Department, Fuel Cycle Science and Technology Division, Nuclear Science and Technology Directorate, Idaho National Laboratory, Idaho Falls, ID 83415, USAA mixed oxide system consisting of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5,</sub> 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% Ta<sub>2</sub>O<sub>5</sub> and 70% Nb<sub>2</sub>O<sub>5</sub> (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 (Nb<sub>4</sub>Ta<sub>2</sub>O<sub>15</sub>) phase, along with Ta<sub>2</sub>O<sub>5</sub> and Nb<sub>2</sub>O<sub>5</sub>, 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 Ta<sub>2</sub>O<sub>5</sub> and Nb<sub>2</sub>O<sub>5</sub> mixed oxides. An oxide composition of 30% Ta<sub>2</sub>O<sub>5</sub> and 70% Nb<sub>2</sub>O<sub>5</sub> (mol%) and a sintering temperature of 950 °C appeared adequate for fabricating well-sintered oxide precursors for subsequent electrochemical polarization studies in fused salts.https://www.mdpi.com/1996-1944/15/14/5036tantalum pentoxideniobium pentoxideenergy materialsoxide precursorsinteringgreen manufacturing |
| spellingShingle | Maureen P. Chorney Kunal Mondal Jerome P. Downey Prabhat K. Tripathy On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide Powders Materials tantalum pentoxide niobium pentoxide energy materials oxide precursor sintering green manufacturing |
| title | On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide Powders |
| title_full | On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide Powders |
| title_fullStr | On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide Powders |
| title_full_unstemmed | On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide Powders |
| title_short | On the Sintering Behavior of Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub> Mixed Oxide Powders |
| title_sort | on the sintering behavior of nb sub 2 sub o sub 5 sub and ta sub 2 sub o sub 5 sub mixed oxide powders |
| topic | tantalum pentoxide niobium pentoxide energy materials oxide precursor sintering green manufacturing |
| url | https://www.mdpi.com/1996-1944/15/14/5036 |
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