Liquid–Solid Equilibria in the System NiO–TiO2–SiO2 in the Temperature Range 1430° to 1660°C |
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Authors: | Nia F Roberts Arnulf Muan |
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Affiliation: | College of Earth and Mineral Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802 |
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Abstract: | Equilibrium relations in the system NiO–TiO2–SiO2 in air have been investigated in the temperature range 1430° to 1660°C. The most conspicuous feature of the phase relations is the existence of a cation-excess spinel-type phase, in addition to NiO and NiTiO3, on the liquidus surface and at subsolidus temperatures down to 1430°C. Three invariant points have been located on the liquidus. There is a peritectic at 1540°C characterized by coexisting NiO ( ss ), spinel( ss ), cristobalite, and liquid of composition 47 wt% NiO, 29 wt% TiO2, and 24 wt% SiO2. Two eutectics are present, one at 1480°C, with spinel( ss ), NiTiO3, cristobalite, and liquid (42 wt% NiO, 43 wt% TiO2, and 15 wt% SiO2), as the coexisting phases. The other is at 1490°C with NiTiO3, rutile, cristobalite, and liquid (32 wt% NiO, 56 wt% TiO2, and 12 wt% SiO2). A liquid miscibility gap extends across the diagram from the two bounding binary systems NiO–SiO2 and TiO2–SiO2. |
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Keywords: | phase equilibria nickel oxide titania silica temperature |
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