Synthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables
Niobium-alumina aggregate fractions with particle sizes up to 3150 µm were produced by crushing pre-synthesised fine-grained composites. Phase separation with niobium enrichment in the aggregate class 45–500 µm was revealed by XRD/Rietveld analysis. To reduce the amount of carbon-based impurities, n...
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oai:doaj.org-article:91fd0ce1d4bf41a594b84d3250f598c62021-11-11T18:01:36ZSynthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables10.3390/ma142164531996-1944https://doaj.org/article/91fd0ce1d4bf41a594b84d3250f598c62021-10-01T00:00:00Zhttps://www.mdpi.com/1996-1944/14/21/6453https://doaj.org/toc/1996-1944Niobium-alumina aggregate fractions with particle sizes up to 3150 µm were produced by crushing pre-synthesised fine-grained composites. Phase separation with niobium enrichment in the aggregate class 45–500 µm was revealed by XRD/Rietveld analysis. To reduce the amount of carbon-based impurities, no organic additives were used for the castable mixtures, which resulted in water demands of approximately 27 vol.% for the fine- and coarse-grained castables. As a consequence, open porosities of 18% and 30% were determined for the fine- and coarse-grained composites, respectively. Due to increased porosity, the modulus of rupture at room temperature decreased from 52 MPa for the fine-grained composite to 11 MPa for the coarse-grained one. However, even the compressive yield strength decreased from 49 MPa to 18 MPa at 1300 °C for the fine-grained to the coarse-grained composite, the latter showed still plasticity with a strain up to 5%. The electrical conductivity of fine-grained composite samples was in the range between 40 and 60 <sup>S</sup>/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula>, which is fifteen magnitudes above the values of pure corundum.Tilo ZienertDirk EndlerJana HubálkováGökhan GünayAnja WeidnerHorst BiermannBastian KraftSusanne WagnerChristos Georgios AnezirisMDPI AGarticlerefractory compositeaggregate synthesiscastableTechnologyTElectrical engineering. Electronics. Nuclear engineeringTK1-9971Engineering (General). Civil engineering (General)TA1-2040MicroscopyQH201-278.5Descriptive and experimental mechanicsQC120-168.85ENMaterials, Vol 14, Iss 6453, p 6453 (2021) |
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DOAJ |
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| topic |
refractory composite aggregate synthesis castable Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 |
| spellingShingle |
refractory composite aggregate synthesis castable Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 Tilo Zienert Dirk Endler Jana Hubálková Gökhan Günay Anja Weidner Horst Biermann Bastian Kraft Susanne Wagner Christos Georgios Aneziris Synthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables |
| description |
Niobium-alumina aggregate fractions with particle sizes up to 3150 µm were produced by crushing pre-synthesised fine-grained composites. Phase separation with niobium enrichment in the aggregate class 45–500 µm was revealed by XRD/Rietveld analysis. To reduce the amount of carbon-based impurities, no organic additives were used for the castable mixtures, which resulted in water demands of approximately 27 vol.% for the fine- and coarse-grained castables. As a consequence, open porosities of 18% and 30% were determined for the fine- and coarse-grained composites, respectively. Due to increased porosity, the modulus of rupture at room temperature decreased from 52 MPa for the fine-grained composite to 11 MPa for the coarse-grained one. However, even the compressive yield strength decreased from 49 MPa to 18 MPa at 1300 °C for the fine-grained to the coarse-grained composite, the latter showed still plasticity with a strain up to 5%. The electrical conductivity of fine-grained composite samples was in the range between 40 and 60 <sup>S</sup>/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula>, which is fifteen magnitudes above the values of pure corundum. |
| format |
article |
| author |
Tilo Zienert Dirk Endler Jana Hubálková Gökhan Günay Anja Weidner Horst Biermann Bastian Kraft Susanne Wagner Christos Georgios Aneziris |
| author_facet |
Tilo Zienert Dirk Endler Jana Hubálková Gökhan Günay Anja Weidner Horst Biermann Bastian Kraft Susanne Wagner Christos Georgios Aneziris |
| author_sort |
Tilo Zienert |
| title |
Synthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables |
| title_short |
Synthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables |
| title_full |
Synthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables |
| title_fullStr |
Synthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables |
| title_full_unstemmed |
Synthesis of Niobium-Alumina Composite Aggregates and Their Application in Coarse-Grained Refractory Ceramic-Metal Castables |
| title_sort |
synthesis of niobium-alumina composite aggregates and their application in coarse-grained refractory ceramic-metal castables |
| publisher |
MDPI AG |
| publishDate |
2021 |
| url |
https://doaj.org/article/91fd0ce1d4bf41a594b84d3250f598c6 |
| work_keys_str_mv |
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