Cation Distribution in Transition Metal Oxide Spinels: Thermodynamic and Kinetic Considerations

1983 ◽  
Vol 24 ◽  
Author(s):  
S. E. Dorris ◽  
D. S. Erickson ◽  
T. O. Mason
Keyword(s):  
Electrical Properties ◽  
Transition Metal ◽  
Metal Oxide ◽  
Cation Distribution ◽  
Transition Metal Oxide ◽  
Thermodynamics And Kinetics ◽  
Oxide Spinels ◽  
Kinetics Of ◽  
Thermoelectric Coefficient ◽  
Defect Reaction

ABSTRACTThe point defect reaction which governs the magnetic and electrical properties of transition metal oxide spinels is the distribution of cations between tetrahedral and octahedral sublattices. Two types of redistribution occur -- ionic and electronic. The thermodynamics and kinetics of these processes can be studied via the electrical properties, thermoelectric coefficient and conductivity.

Elasticity of franklinite and trends for transition-metal oxide spinels

2013 ◽  
Vol 98 (4) ◽  
pp. 601-608 ◽  
Author(s):  
H. J. Reichmann ◽  
S. D. Jacobsen ◽  
T. B. Ballaran
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Transition Metal Oxide ◽  
Oxide Spinels

The kinetics of crystal growth in an aluminosilicate glass containing small amounts of transition-metal ions

1970 ◽  
Vol 37 (291) ◽  
pp. 759-770 ◽  
Author(s):  
J. Williamson
Keyword(s):  
Activation Energy ◽  
Crystal Growth ◽  
Transition Metal ◽  
Metal Oxide ◽  
Transition Metal Oxide ◽  
Transition Metal Ions ◽  
Aluminosilicate Glass ◽  
Kcal Mole ◽  
Kinetics Of ◽  
Kinetics Of Crystal Growth

SummaryQuantitative data are presented for the kinetics of crystal growth in an aluminosilicate glass to which a few wt % of a transition-metal oxide had been added. The composition of the base glass was CaO 3o, MgO 2, Al2O3 15, SiO2 53 wt %, to which the oxides of iron, vanadium, chromium, or zinc were added. Glasses were prepared with a range of high to low valency ratios in cases where the transition metal oxide could exist in two or more oxidation states.Small quantities of Fe2+, Fe3+, Zn2+, V3+, V4+, and V5+ were all found to increase the kinetics of crystal growth from the glass phase. The magnitude of the effect is compared with additions of Mg2+ to the glass. Cr2+, Cr3+, and Cr6+ were found to decrease the rates of crystal growth. Values for the apparent activation energy for crystal growth ranged from ∼50 kcal/mole to ∼150 kcal/mole. The high values were found to be of the same order of magnitude as that for the activation energy for viscous flow in the glass at the crystallization temperature.The results are interpreted in terms of the structure of the glasses and current theories on the rate of crystallization of glasses.

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