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An In Situ High‐Temperature X‐Ray Diffraction Study of Early‐Stage Crystallization in Lithium Alumosilicate Glass–Ceramics
Author(s) -
Dressler Martina,
Rüdinger Bernd,
Deubener Joachim
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.04252.x
Subject(s) - crystallization , analytical chemistry (journal) , materials science , lattice constant , crystal (programming language) , diffraction , crystallography , mineralogy , chemistry , optics , chromatography , physics , organic chemistry , computer science , programming language
In situ high‐temperature X‐ray diffraction data have been collected for the crystallization of high‐quartz solid solution (hq‐ss) in a Li 2 O–Al 2 O 3 –SiO 2 glass–ceramic. The temporal development of the number density, size, and unit cell parameters of hq‐ss crystals indicated a two‐stage crystallization process. At the early stage, lattice parameters of hq‐ss crystals were constant. Their number density increased at a maximum rate of 1.7 × 10 12 ·(mm 3 ·min) −1 up to 1.4 × 10 14 mm −3 , while hq‐ss grew linear with time at a maximum rate of ≈1 nm/min up to a size of ≈21 nm. In contrast, a decrease of the a ‐unit cell parameter, characteristic for increasing Si/Al ratios of the hq‐ss crystals, was evident at the later stage. At this stage, the average crystal size was >21 nm. Their number density was constant or decreased linearly with time. The growth kinetics were very shallow with the exponent ≈1/50, but reached for crystals >30 nm cube root dependence typical for diffusion‐controlled ripening. Avrami analysis of the volume fraction V f confirmed these findings and resulted in a kinetic exponent in the range from 3.5 to 4.8 for the first ( V f <45%) and <0.3 for the second stage.