Grain-enhancing compound

Potent recrystallization-inhibitors will also be useful as additives to prevent recrystallization in materials such as grain oriented silicon steel or silicon-iron composites (22, 23). In a different venue, such compounds have applications in the food industry to enhance the texture and tastes of various frozen food products. 

Another possibility that could explain Lith development is the apparently contradictory phenomenon of bleach enhanced fog or BEF [70]. In this case compounds known as silver bleaches can cause fog in grains with sub-developable silver centers. Two-atom silver centers cannot initiate development and would be bleached by oxidants, for example, benzoquinone, to a one-atom silver center. A single silver atom is thermally unstable and can dissociate, without the need for an oxidant, into a silver ion and a mobile conduction-band electron. If several two-atom centers are present on a grain, a developable center can arise from the accumulation of these mobile electrons at a suitable site. 

Preparation of a peritectic compound requires a solid state (solid-solid) or solid-liquid reaetion. A solid state reaction requires transport of matter (diffusion) in the direetion of a chemical potential gradient (i.e., a chemical composition gradient). Thus solid state reactions are diffusion controlled, with diffusion fastest across grain boundaries. Within a crystal, diffusion is enhanced by defects. Clearly the preparation of a peritectic alloy should be carried out at the highest possible temperature just below the peritectic decomposition temperature. The speciality of powder metallurgy exploits the optimum conditions for solid state reactions. 

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