Measurements of grain boundary properties in nanocrystalline ceramics

Thermodynamics of Nanostructured Materials

“…Solution calorimetry shows the excess free energy of the nanocrystalline material to be in the range 6 to 10 kJ mol-1 , corresponding to a grain boundary free energy of 0.25 to 0.5 J m-2 . These values are similar to those quoted above for nanocrystalline Pd, though they may be underestimated [27]. It is suggested that reasonable values for the grain boundary energy would be 1 to 2 J m-2 .…”

“…Chiang et al [27] have studied nanocrystalline SiC produced in fibre-form by chemical decomposition. The material consists of single-phase cubic SiC of grain diameter -3 nm, but with oxygen impurities in the grain boundaries.…”

Interface Energy Measurement of MgO and ZnO: Understanding the Thermodynamic Stability of Nanoparticles

“…Among the techniques for interface energy measurements reported in the literature, image analysis providing dihedral angle measurements has been used extensively to derive relative energies. This technique, however, has been considered problematic because of surface faceting and also because of the inherent curvature potential that leads to dihedral angle increase . Drop solution calorimetry using dense nanograined ceramics was also proposed as a method to obtain absolute γ SS values .…”

“…Chen and Spaepen explored DSC to extract parameters that characterize the grain growth and used them to derive the surface energy of a metal alloy. Chiang et al used a similar approach to determine the interface energy of Si and TiO 2 . In such an approach, a grain growth model was used and needed a geometric factor accounting for the grain shape and size distribution.…”