Effect of Oxygen Vacancies on the Hot Hardness of Mullite |
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| Authors: | James E Pitchford Robert J Stearn Anthony Kelly William J Clegg |
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| Affiliation: | Department of Materials, University of Cambridge, Cambridge CB2 3QZ, United Kingdom |
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| Abstract: | The structure of mullite, which has a composition ranging from 3Al2O3·2SiO2 to Al2O3·2SiO2, contains ordered oxygen vacancies. Sillimanite, Al2O3·SiO2, has a similar structure but with no vacancies. The indentation hardness of polycrystalline mullite (3Al2O3·2SiO2) was measured from room temperature up to 1400°C and compared with that of single-crystal sillimanite (Al2O3·SiO2) up to 1300°C. It was found that both materials show the same variation in hardness with temperature, suggesting that the structures have a similar resistance to plastic deformation, and therefore that the oxygen vacancies in the mullite structure are not the primary cause of mullite's resistance to high-temperature deformation. |
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| Keywords: | oxygen vacancies mullite |
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