Equilibrium Phase Relations of the CaO-SiO2-Ti3O5 System at 1400 °C and a p(O2) of 10−16 atm

SummaryThe liquidus temperature (1198 °C) and equilibrium phase relations of a sample of Columbia River basalt from the Picture Gorge section have been determined at I atmosphere by heating in a controlled atmosphere. When this basalt is cooled from above its liquidus temperature the liquidus phase (plagioclase) may fail to crystallize depending on the degree of undercooling and the duration of the experiment. A field in temperature-time space in which plagioclase fails to crystallize on cooling is separated from another in which plagioclase always crystallizes by a third in which the nucleation of plagioclase is unpredictable in terms of temperature and time. The extent to which this basaltic liquid can be supercooled without the crystallization of plagioclase is independent of the time it is held above the liquidus or the temperature in excess of the liquidus to which it is heated.The exceptionally long times required to ensure the nucleation of plagioclase at or near the liquidus temperature suggest that many so-called ‘equilibrium’ phase relations determined from experiments of a few hours' duration could be in serious error if the ‘equilibration’ involves a nucleation process.It is demonstrated that, over a range of cooling rates, the temperature at which plagioclase begins to crystallize on cooling varies markedly and the temperature and times required for both possible and certain nucleation of plagioclase are calculated for a range of constant cooling rates. The range of cooling rates over which the nucleation temperature of plagioclase varies is likely to occur in nature only in certain lava flows and small minor intrusions. In such cases this could lead to changes in the order in which the minerals appear on cooling and other petrologically significant effects.

Download Full-text

Internally consistent thermodynamic data and equilibrium phase relations for compounds in the system MgO-SiO2at high pressure and high temperature

Journal of Geophysical Research Atmospheres ◽

10.1029/jb095ib05p06915 ◽

1990 ◽

Vol 95 (B5) ◽

pp. 6915 ◽

Cited By ~ 99

Author(s):

Yingwei Fei ◽

Surendra K. Saxena ◽

Alexandra Navrotsky

Keyword(s):

High Pressure ◽

High Temperature ◽

Thermodynamic Data ◽

Equilibrium Phase ◽

Phase Relations ◽

Consistent Thermodynamic Data

Download Full-text

Equilibrium phase relations in the Bi–Ca–Sr–Cu–O system at 850 and 900°C

Journal of Materials Research ◽

10.1557/jmr.1990.1403 ◽

1990 ◽

Vol 5 (7) ◽

pp. 1403-1408 ◽

Cited By ~ 41

Author(s):

C-L. Lee ◽

J-J. Chen ◽

W-J. Wen ◽

T-P. Perng ◽

J-M. Wu ◽

...

Keyword(s):

Solid Solution ◽

Powder Diffraction ◽

Equilibrium Phase ◽

Superconducting Phase ◽

Phase Relations ◽

The Other ◽

Boundary Line ◽

X Ray ◽

Tie Lines ◽

Boundary Lines

The phase relations of equilibrium compounds in the pseudoternary system Bi2O3–(Ca,Sr)O–CuO at 850 and 900°C were studied. The ratio of Ca : Sr was fixed at 1:2. Starting materials of Bi2O3, CaCO3, SrCO3, and CuO with various ratios were mixed, pressed into pellets, and heated at or above and then brought back to 850 or 900°C for different durations to ensure that equilibrium had been reached. The products were cooled in air or quenched in liquid nitrogen and then identified by x-ray powder diffraction. At 850°C, only the superconducting phase, Bi2CaSr2Cu2Ox (2122), was observed inside the triangle. The other stable phases were all positioned on the boundary lines, and included CuO·⅗MO, CuO·MO, CuO·2MO, 1.½Bi2O3·0.9MO, Bi2O3·4MO, Bi2O3·9MO, and a solid solution, Bi2O3·xMO, where 0.16  x  0.82 and MO represents ⅓(CaO·2SrO). At 900°C, the above boundary line phases remained stable but the 2122 phase was not observed. The tie lines among the stable phases in the two isotherms were established.

Download Full-text

Effect of Oxygen Partial Pressure and Temperature on Liquidus for the CaO-SiO2-FeOx-Al2O3 System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.295-297.2279 ◽

2011 ◽

Vol 295-297 ◽

pp. 2279-2282 ◽

Cited By ~ 1

Author(s):

Nan Wang ◽

Zong Shu Zou ◽

Zhan Zhang ◽

Yan Xiao ◽

Yong Yang

Keyword(s):

Thermodynamic Properties ◽

Oxygen Partial Pressure ◽

Partial Pressure ◽

Equilibrium Phase ◽

Bottom Ash ◽

Oxide System ◽

Phase Relations ◽

Efficient Utilization ◽

Oxide Systems ◽

Effect Of Oxygen

To provide essential data for an efficient utilization of vitrified bottom ash slag, the thermodynamic properties of the CaO-Al2O3-SiO2-FeOx-MgO-Na2O oxide system is highly required. As one of the related oxide subsystems, the equilibrium phase relations and liquidus of CaO-SiO2-FeOx-Al2O3 system is of great significance to interpret and predict the thermodynamic properties in multi-component oxide systems. In this paper, phase diagrams for the CaO-Al2O3-FeOx and SiO2-Al2O3-FeOx systems were calculated by using CALPHAD method with FactSage program. The liquid phase area changed with changing oxygen partial pressure from 1Pa to 10-3Pa and temperature from 1673K to 1773K. The equilibrium phase relations of CaO-Al2O3-FeOx and SiO2-Al2O3-FeOx systems were discussed.

Download Full-text