Interparticle necks

Initial Rapid interparticle neck growth 0.65 Two monosized spheres in contact... 

Svoboda J, Riedel H (1995) New solution describing the formation of interparticle necks in solid-state sintering. Acta Metall Mater 43 1-10... 

Table 13.3 summarizes the polymeric systems that have been applied to silica. In effect, the underlying inorganic framework plays the role of a structure-directing agent (template). The mechanical property improvement is attributed to reinforcement of the interparticle necks, which are the weak points of the aerogel skeletal framework. In turn, the stabilization provided by the crosslinking polymer is attributed to the extra chemical bonds created by the interparticle polymeric tethers. 

Figure 5.14. Formation of interparticle necks. Top, solution and redeposition process rearrangement of silica bottom, deposition process of additional silica. Dashed lines original silica spheres before reinforcement.

Establishment of inexpensive fabrication process for making dense films of LaCrOs-based ceramics. This is because the sintering of LaCrOs in ir is quite difficult since the chromium component tends to volatilize during sintering and to subsequently deposit at interparticle necks as Cr203 This deposited chromia hinders further sintering [10]. 

This physical picture is reasonably consistent with the TEM micrograph shown in Fig. 11, although the estimate of the particle size is somewhat high. An overestimate of the particle size, based on Eq. 1, means that the surface area is less than that expected for particles of the equivalent spherical diameter observed by TEM. This indicates that the interparticle contacts are necked or deformed. According to Meissner et at. [14] the ratio of cavity radius to throat radius should equal about 1.4 for spheres compacted to a coordination number of about 8. The ratio obtained from values of the average pore sizes derived from the adsorption and desorption branches of the nitrogen isotherm was closer to 1.3, consistent with some interparticle neck formation. 

Simultaneous measurement of grain growth to determine if the grain boundaries migrate away from the interparticle necks. 

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