Grain impurity segregation

Application of AES to zirconia ceramics has been reported by Moser et al. [2.146]. Elemental maps of Al and Si demonstrate the grain boundary segregation of small impurities of silica and alumina in these ceramics. 

The mechanical properties of ceramics maybe increased by minimising impurity segregation, decreasing grain size and increasing sintered density. 

Grain Boundary Segregation of Impurity in Polycrystalline Silicon... 

For the SoG-Si polycrystalline silicon, both the XGB and X are far less than unity. Furthermore, if the impurities follow Henry s law, e.g., (13.6), the effect of the excess Gibbs energy on the grain boundary segregation can be neglected. Equation (13.20) may, thus, be simplified to pcpc... 

A more sophisticated approach for determination of the grain boundary segregation is similar to the determination of the surface tension of silicon melt. The novel approach of surface tension simulation has been successfully implemented in the thermochemical database. Hence, the assessment of the parameters for impurity segregation in solid silicon phase may greatly extend the application of the thermochemical database. The calculation results for C and O segregation are shown as dashed lines in Fig. 13.28. The McLean segregation isotherm can be reproduced using the approach similar to the surface tension simulation. 

Solute and impurity segregation to grain boundaries in polycrystalline solids is known to affect mechanical properties and engineering performances of these materials. 

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