UBC Theses and Dissertations
Deformation of compacts of magnesium hydroxide during dehydroxylation Sunderland, Philip William
The deformation behaviour of polycrystalline compacts of Mg(OH)₂ during dehydroxylation has been studied in an attempt to evaluate the nature of strain that can be introduced into the compact during the reaction. A study of neck-growth between tips of single crystals of Ca(OH)₂, and between two hemispherical tips of Mg(OH)₂, compacts showed both deformation and interaction at the contact point during the dehydroxylation reaction. Load-dependent deformation of the compacts gave a total strain proportional to the one-third power of the applied stress. The creep deformation of Mg(OH)₂ compacts during dehydroxylation was also studied under isothermal conditions. The overall creep behaviour can be divided into three stages. The initial stage is initiated by the dehydroxylation reaction. During the second or steady state creep stage the highest creep rate was obtained. The steady state creep rate was determined as a function of temperature pressure, and relative density of the green compact. The results are represented by: [formula omitted] Particle sliding was considered to be the most probable mechanism for creep during the second stage.
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