Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751608
Title: Thermal decomposition of transition-metal hydroxides
Author: Hazell, Ian Frank
ISNI:       0000 0001 3550 0441
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1964
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Abstract:
Previous studies of the process of corrosion of steel by superheated alkaline water have shown that the formation and subsequent decomposition of ferrous hydroxide may be responsible for some of the magnetite scale found in operating boilers. With the increasing use of alloy steels, the properties of cobalt and nickel hydroxides under these conditions are also of interest. There is reason to expect that the mechanism of the decomposition will be the same under hydrothermal conditions as for the dry solid and accordingly, kinetic studies of the decompositions have been made in air and in vacuo where appropriate. Both isothermal and non-isothermal methods have been used to obtain kinetic parameters. Previous methods for analysing non-isothermal data have been found to be unreliable and a new approach has been devised which gives results in agreement with isothermal studies. The similarity of the reaction under hydrothermal conditions has been confirmed by autoclave experiments. Ferrous, cobaltous and nickelic hydroxides all have the magnesium hydroxide structure and so similarities in the mode of decomposition are to be expected. For example, decompositions should be topotactio processes with a definite ciystallographic orientation between starting material and product. This has been confirmed by X-ray studies for the nickel hydroxide-nickel oxide system. The intensities of X-ray reflexions from nickel hydroxide have been investigated as considerable discrepancies exist between the results of earlier wrorkers. A good agreement between our experimental results and calculated values has been obtained. The factors influencing the course of the reaction under various conditions are discussed and possible mechanisms examined.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.751608  DOI: Not available
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