Destruction of monocrystals of potassium dihydrophosphate in the process of heating

Autor: Atroshchenko, L., Kolybaeva, M., Rom, M., Salo, V., Tkachenko, V., Khodeeva, N.
Zdroj: Materials Science; September 1996, Vol. 31 Issue: 5 p583-587, 5p
Abstrakt: We study the effect of isothermal annealing of KH2PO4 monocrystals in the temperature range 180–210°C on the quality of their structure and phase composition by the method of X-ray diffraction analysis and microscopically. It is shown that in the process of heating followed by cooling, the specimens undergo both the phase transition from the tetragonal to monoclinic modification and the inverse transition, namely, $$\bar 4$$ 2m → P21 → $$\bar 4$$ 2m, and these transitions are accompanied by the structural transition from monocrystals to polycrystals. This leads to the formation of a branched system of microcracks and, as a result, to the turbidity and degradation of the material. The indicated processes are explained by the great difference between the lattices of the tetragonal and monoclinic phases and stresses formed in the course of these phase transformations.
Databáze: Supplemental Index
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