Chemical-electric energy conversion effect in zirconia nanopowder systems

Abstract

Issues concerned with the energy conversion of exothermal heterophase processes are discussed using the physico-chemical interaction between ZrO 2-Y 2 O 3 (3 mol %) nanopowder system and atmospheric moisture as an example. The electrical properties of an experimental sample are investigated upon moisture saturation in the case of a molecular-flow density gradient. A probable mechanism for the effect based on the theory of contact phenomena in semiconductors is proposed. The idea of developing chemical-electric converters fabricated from nanoscale materials with dielectric conduction is suggested.

Martensitic Phase Transition in Yttrium-Stabilized ZrO2 Nanopowders by Adsorption of Water

“…The established effect as one of the forms of recharging of oxide nanoparticles surface layer, confirms the adsorption mechanism of electron emission in ZrO2-3mol%Y2O3 described in [7,8,33,34].…”

“…The thermodynamic approach allows us to draw another important conclusion about the mechanism of T-M transformation in nanoparticles: for it to be realized, it is necessary to change the surface energy of the nanoparticle significantly. The probable mechanisms of this process are associated with a change in the physicochemical and electronic properties of the surface of nanoparticles by adsorbates (OHgroups) (Adsorption mechanism of T-M phase transformation [7][8]12]). Estimates of the corresponding structural parameters (level of microstresses, sizes of unit cells, etc.)…”

“…Thus, Raman spectroscopy confirmed neutron and X-ray diffractions data about adsorption-induced formation of the monoclinic phase in ZrO2-3mol%Y2O3 nanopowders. A probable mechanism of tetragonal-monoclinic phase transformation in ZrO2-nanoparticles was discussed in [7][8] and is showed schematically on Fig. 5.…”

“…It is commonly assumed that in nanoparticles smaller than 30 nm t-m transformations cannot be realized due to the lack of the necessary volume for accumulation of stresses and propagation of the phase transformation front [5,6]. However, the results of [7,8], in which the effect of the so-called "chemoelectronic conversion" was shown, indicates that the t -m transformation still can be able in nanoscale objects. The confirmation of this fact is extremely interesting task as for fundamental science as for applications, in particular, adsorption electronics, alternative energetics and so on.…”

Reversible Martensitic Phase Transition in Yttrium-Stabilized ZrO2 Nanopowders by Adsorption of Water

“…It is commonly assumed that in nanoparticles smaller than 30 nm, T-M transformations cannot be realized due to the lack of the necessary volume for accumulation of stresses and propagation of the phase transformation front [ 5 , 6 ]. However, the results of [ 7 , 8 ], in which the effect of the so-called “chemoelectronic conversion” was shown, indicates that the T-M transformation still can be able in nanoscale objects. Moreover, it is shown that in nanoparticles, this transition has a reversible character.…”