Liquid phase behaviour in nonstoichiometric calcium-doped lanthanum chromites
| Autor: | J. D. Carter, M. M. Nasrallah, Harlan U. Anderson |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Materials science
Mechanical Engineering technology industry and agriculture Sintering Mineralogy chemistry.chemical_element equipment and supplies Microstructure Grain growth Chemical engineering chemistry Mechanics of Materials Phase (matter) Lanthanum General Materials Science Wetting Porosity Phase diagram |
| Zdroj: | Journal of Materials Science. 31:157-163 |
| ISSN: | 1573-4803 0022-2461 |
| Popis: | The sinterability of (La,Ca)CrO3 is analysed by comparing the liquid phase behaviour in A-site excess and A-site deficient compositions (referring to the ABO3 formula). The analysis shows that a series of A-site excess and deficient compositions form distinct liquid phases belonging to the CaO-Cr2O3 phase system. Although both series experience grain growth and densification due to the presence of a liquid phase, the A-site excess compositions exhibit greater shrinkage and sinter to closed porosity, whereas the A-site deficient compositions remain porous. During the final stages of sintering, surplus liquid from the A-site excess material exudes to the free-surface forming a layer of uniform thickness. By comparison, the liquid in the A-site deficient composition segregates to the free-surface forming islands and leaving porous regions in the bulk matrix. It is concluded that the different liquid phase compositions in the A-site excess and A-site deficient (La,Ca)CrO3 have dissimilar wetting characteristics during the later stages of sintering. The A-site deficient liquid forms a premature solid phase, which accounts for the difference in sintering behaviour. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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