Heat stability, consolidant

The dimensional and mechanical stability of materials is of paramount importance to their use in the everyday world where they may encounter a wide variation in temperature through design or by accident. Many polymers are processed at elevated temperatures so as to enable them to flow and be more amenable to fabrication. Food items are cooked, pasteurised or otherwise heated or frozen. Ceramics are fired so as to consolidate their final structure. The relationship between a material s dimensional and mechanical properties and its temperature is studied by the techniques described within this chapter and, due to common concepts, the effect of heat on the electrical properties of materials is also considered. 

The well-known nonequilibrium process of plasma chemical synthesis has found practical application for a large number of compounds and compositions. However, in recent years more attractive and well-developed processes of synthesis become gas phase condensation under quasi-equilibrium conditions of moderate heat and mass transfer. This process becomes preferable over latter plasma chemical synthesis due to its ability to control the thermal regime and more flexibility in regard to dispersion and purity of the synthesized product. Uniformity of particle size and chemical composition (powder purity) are essential for fabrication of nanocomposites or dense nanocrystalline materials with improved physical, chemical and mechanical properties. This is because the particle size distribution determines the stability of grains during consolidation of a polycrystal while the concentration of impurities affects properties of grain boundaries and entire material (Table 5.1). 

Electric meter bases capitalize on SPS s excellent electrical insulation and ease of processing, which in turn permits cost reductions through parts consolidation. Various appliance components take advantage of SPS s hydrolytic, heat, and dimensional stability, including coffee makers, garbage compactors, humidifiers, and washer/dryer components. 

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