Crystallization kinetics of yttrium aluminate glasses
- 64 Downloads
Yttrium aluminate glasses with eutectic AY-E and near-eutectic composition AY-NE were prepared in the form of glass microspheres. Their basic characterization was carried out by XRD, optical microscopy and SEM. In DSC records of both samples, two exothermic peaks in temperature interval 940–1027 °C were observed. In both samples, YAG phase crystallized in two steps, as determined by HT XRD. DSC experiments conducted in the temperature interval 35–1200 °C at heating rates 2, 4, 6, 8 and 10 °C min−1 were performed, and the kinetic parameters of crystallization were determined with the use of the JMAK model. Crystallization in both samples was controlled by diffusion flow with linear nucleation rate time dependence. One-dimensional growth and formation of needle-like (dendritic) YAG crystals was observed in AY-E glass crystallized at 932 °C corresponding to the first exothermic maximum at the DSC curve. Two-dimensional growth and the presence of plate-like YAG crystals were observed in AY-NE glass crystallized at 996 °C. For the second exothermic effect, plate-like crystals crystallized at higher temperatures (996 and 1020 °C) in both compositions. The results of SEM analysis are in agreement with the results of kinetic calculations in the prepared systems.
KeywordsCrystallization kinetics HT XRD DSC Yttrium aluminate glasses
The financial support of this work by the project SAS-MOST JRP 2015/6, VEGA 1/0631/14, VEGA 2/0026/17 and APVV 0014-15 is gratefully acknowledged. This publication was created in the frame of the project “Centre of excellence for ceramics, glass, and silicate materials” ITMS code 262 201 20056, based on the Operational Program Research and Development funded from the European Regional Development Fund.
- 7.Dianguang L, Yan G, Jinling L, Fangzhoung L, Kai L, Haijun S, Yiguang W, Linan A. Preparation of Al2O3–Y3Al5O12–ZrO2 eutectic ceramic by flash sintering. Scr Mater. 2016;14:108–11.Google Scholar
- 15.Prnová A, Galusek D, Hnatko M, Kozánková J, Vávra I. Composites with eutectic microstructure by hot pressing of Al2O3–Y2O3 glass microspheres. Ceram Silik. 2011;55:208–13.Google Scholar
- 16.Šesták J, Šimon P, editors. Thermal analysis of micro, nano- and non-crystalline materials: transformation, crystallization, kinetics and thermodynamics. New York: Springer; 2013. p. 225–46.Google Scholar
- 20.Kolmogorov AE. On the statistic theory of metal crystallization. Izv Akad Nauk SSSR Ser Mat. 1937;1:355–9 (in Russian).Google Scholar
- 21.Johnson WA, Mehl RF. Reaction kinetics in processes of nucleation and growth. Trans Am Inst Min Metall Pet Eng. 1939;135:416–58.Google Scholar
- 28.Akaike H. Information theory and an extension of maximum likehood principle. In: Petrov BN, Csáki F, editors. 2nd international symposium on information theory. Budapest: Akadémia Kiadó; 1973. p. 267–81.Google Scholar
- 32.Pechini MP. Method of preparing lead and alkaline-earth titanates and niobates and coating method using the same to form a capacitor. US Patent No. 3 330 697, 1967.Google Scholar