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3D microstructure of magnesium potassium phosphate ceramics from X-ray tomography: new insights into the reaction mechanisms
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SYSNO ASEP 0496962 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title 3D microstructure of magnesium potassium phosphate ceramics from X-ray tomography: new insights into the reaction mechanisms Author(s) Viani, Alberto (UTAM-F) RID, ORCID, SAI
Sotiriadis, Konstantinos (UTAM-F) RID, ORCID, SAI
Lanzafame, G. (IT)
Mancini, L. (IT)Number of authors 4 Source Title Journal of Materials Science. - : Springer - ISSN 0022-2461
Roč. 54, č. 5 (2019), s. 3748-3760Number of pages 13 s. Publication form Print - P Language eng - English Country US - United States Keywords magnesium potassium phosphate ceramics ; 3D microstructure ; synchrotron X-ray computed microtomography Subject RIV JN - Civil Engineering OECD category Materials engineering R&D Projects LO1219 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Method of publishing Open access UT WOS 000452712800005 EID SCOPUS 85056575816 DOI 10.1007/s10853-018-3113-7 Annotation Magnesium potassium phosphate ceramics are chemically bonded ceramics employed as biomaterials, in nuclear waste encapsulation and for concrete repair. The microstructure dictates material performance and depends on the raw mix composition. Synchrotron X-ray computed microtomography was employed to describe the 3D microstructure and its time evolution during hardening and gain insights into the reaction mechanisms. Any excess water with respect to the stoichiometry of the reaction brought about an increase in porosity, but, notably, a reduction in the average pore size. Crystals filled the water ‘pockets’ in the ceramic volume by growing larger, although less densely packed, increasing the complexity of the pore shape. Platelet over elongated crystal habit was favoured. Such a change in shape is likely related to a change in reaction mechanism, as crystallization from a gel-like amorphous precursor is hindered and progressively substituted by a through-solution mechanism. It is proposed that the time evolution of the microstructure is dictated by the balance between crystallization from amorphous precursor, prevailing in relatively ‘dense’ systems (with stoichiometric water or in low excess), and water segregation, prevailing at higher water contents. The former mechanism was shown to produce an increase in porosity with time, because of the density mismatch between the amorphous and the crystalline phase Workplace Institute of Theoretical and Applied Mechanics Contact Kulawiecová Kateřina, kulawiecova@itam.cas.cz, Tel.: 225 443 285 Year of Publishing 2020 Electronic address https://doi.org/10.1007/s10853-018-3113-7
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