Water-Sorption Effects near Grain Boundaries in Modified MgO-Al2O3 Ceramics Tested with Positron-Positronium Trapping Algorithm

H. Klyma, A. Ingram b, O. Shpotyukc,d,e, I. Hadzaman f and D. Chalyy g aLviv Polytechnic National University, 12 Bandery Str., Lviv, 79013, Ukraine bOpole University of Technology, Ozimska 75, 45-370 Opole, Poland cVlokh Institute of Physical Optics, 23 Dragomanova Str., Lviv, 79005, Ukraine dJan Dlugosz University of Czestochowa, al. Armii Krajowej 13/15, 42-201 Czestochowa, Poland eScientific Research Company "Carat", 202 Stryjska Str., Lviv, 79031, Ukraine fDrohobych Ivan Franko State Pedagogical University, 24 I. Franko Str., Drohobych, 82100, Ukraine gLviv State University of Life Safety, 35 Kleparivska Str., Lviv, 79000, Ukraine

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Water-sorption processes near grain boundaries in the MgO-Al2O3 ceramics prepared at different temperatures were studied using positron annihilation lifetime spectroscopy. Numerical values of three- and four-component treatment of spectra were used for study of physical- and chemical-sorption processes in the MgO-Al2O3 ceramics. To apply mathematical approach in the form: of positron-positronium trapping algorithm into three-component treatment of positron annihilation lifetime spectra it was shown that physical-adsorbed water did not modify positron trapping sites near grain boundaries in water-immersed MgO-Al2O3 ceramics and localized mainly in nanopores. The chemically-adsorbed water modifies structural extended defects located near grain boundaries that accompanied them by void fragmentation at water desorption.

DOI: 10.12693/APhysPolA.133.824 PACS numbers: 81.05.Je, 07.07.Df