engleski

Phases in the system Ba_2SiO_4-Ca_2SiO_4

The system Ba_2SiO_4-Ca_2SiO_4 was studied by heating mixtures of Ba_2SiO_4 and Ca_2SiO_4 at 1723 K. Six distinct phases resulted ; they were examined by both X-ray diffraction and differential thermal analysis. The phases beta-(Ba_0.05Ca_1.95)SiO_4 and alpha-(Ba_0.15Ca_1.85)SiO_4 are isostructural with corresponding high-temperature modification of Ca_2SiO_4. The X phase -(Ba_0.48Ca_1.52)SiO_4 is orthorhombic, is a pure phase rather than a solid solution, and is defined for the first time in the present work. The T phase -(Ba_1.31Ca_0.69)SiO_4 is a hexagonal and interpreted in terms of a unit cell with a doubled c parameter, in contrast with literature data.

barium silicate ; calcium silicate ; X-ray diffraction ; differential thermal analysis

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