Measurement of Solid State Reactions

8) Precipitation is usualfy homogeneous. Formation of embryos which grow into nuclei which grow into particles suspended in the mother-liquor will vary according to the precipitation temperature, concentration of reacting components and method of addition. 

Particles can grow into larger particles either due to Ostwald Ripening (in solution) or by sintering (solid state). 

Particles that are too small cannot sinter to grow into IcU ger particles. 

Particles that are formed by either precipitation or sintering form grain boundaries within each individual crystallite. This is due to consolidation of the very small crystallites, having a large surface area, into larger crystallites, having a decreased surface area. 

We have now examined the factors involved in solid state reactions and particle growth. Nucleation, particle growth and diffusion mechanisms were the main theme of our discussion of solid state reactions, but we have not addressed how we can obtain a measure of solid state reactions as they occur. That is, how do we measure how the reaction occurs The next section shows how DTA and TGA are applied to the decomposition and reaction of solids. 

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Theron C C, Mars J A, Churms C L, Farmer J and Pretorius R 1998 In situ, real-time RBS measurement of solid state reaction in thin films Nuol. Instrum. Methods B 139 213... 

The Solid State Mechanisms of Nucleation, Solid State Diffusion, Growth of Particles and Measurement of Solid State Reactions... 

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