Crystallinity influence, cohesion materials

One may expect that with increasing temperature the thermal expansion in the crystalline regions will lead to an enlargement of the chain cross-section in the crystalline phase which in turn will induce a decrease in the cohesion energy of the crystals thus causing a gradually lower resistance to plastic deformation. In order to minimize the effect of the surface layer, the influence of temperature on microhardness has been investigated in PE crystallized at 260 °C under a pressure of 5 Kbar 28). The decrease of MH with temperature for the above chain extended PE material is depicted in Fig. 11. The hardness decrease follows an exponential law... 

Abstract Refractory oxides encompass a broad range of unary, binary, and ternary ceramic compounds that can be used in structural, insulating, and other applications. The chemical bonds that provide cohesive energy to the crystalline solids also influence properties such as thermal expansion coefficient, thermal conductivity, elastic modulus, and heat capacity. This chapter provides a historical perspective on the use of refractory oxide materials, reviews applications for refractory oxides, overviews fundamental structure-property relations, describes typical processing routes, and summarizes the properties of these materials. 

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