Self-organization processes in nanopowder dispersed system based on zirconia under pressure action

The work is devoted to the studying of mechanisms of zirconia nanoparticles growth (enlargement) in temperature region were diffusion processes isn’t beginning. A comparative analysis of morphology of compacted using high hydrostatic pressure ZrO2 + 3 mol% Y2O3 nanopowders (YSZ, particle size 9 nm) with different content of adsorbed moisture was conducted. The fact of granulation on a microscopic size scale of initially uniformly distributed dispersed phase with adsorbed water content of 11.5% was established. The results were considered by using thermodynamic principles of nanosized dispersed systems self-organization. The different precursors and external pressure was considered as a critical factor in the destabilization of the self-organization process at room temperature. It was shown that the observed effect is a form of manifestation of coagulation process in the studied dispersed system at room temperature range which is hidden under normal pressure. Conclusion about coagulation nature of growth process of ZrO2 nanoparticles at temperature range where thermal diffusion is still missing was done. The suggestion that widespread models of low-temperature growth of nanoparticles based on collective effects (orientation growth), which is suggest the orienting action of crystalline environment fields as a thermodynamic stimulus of growth processes, are a particular cases of manifestation of the overall coagulation process.

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