Ask for a reprint
email :
* Give your email
2023
ACL
|
A.Prnová, J.Valúchová, M.Parchovianský, P.Švančárek, F.Šimko, A.Rakhmatullin, H.Pálková, H.Branislav, R.Klement, D.Galusek, 'Structure, thermal properties and crystallization behavior of binary Y2O3–Al2O3 glasses with high alumina content', J. Mat. Res. Technol. 26 2333-2351 (2023) doi:10.1016/j.jmrt.2023.08.067
Five compositions in the system Al 2 O3eY 2O 3 with high level of homogeneity were prepared in the form of glass microspheres by flame synthesis. The amorphous nature of prepared glasses with highly disordered structure was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman and nuclear magnetic resonance (NMR) spectroscopy. In the NMR spectra, typical signals with chemical shifts of 75, 42 and 12 ppm were observed, which were attributed to the presence of AlO4, AlO 5 and AlO 6 motifs in the glass structure. The ratio of individual motifs in glass samples did not change significantly with the composition. The crystallization of yttrium-aluminium garnet (YAG) phase was observed as a major process in the glasses thermally treated up to 1450 C, with slow crystallization of q- and a-Al 2O3 phases detected in the temperature interval 980e1450 C. IR and Raman spectra of the microspheres crystallized at 998, 1300 and 1500 C for 4 h contained typical bands, that were assigned to the vibrations of AlO 4 and AlO 6 groups in YAG and Al 2O3 structures. The comparison of 27Al and 89Y magic angle spinning (MAS) NMR spectra showed the presence of only YAG and a-Al2 O3 phase in the samples crystallized at 1500 °C and the presence of a trace amount of q-Al2 O3 in the sample crystallized at 998 and 1300 °C. The yttrium aluminium perovskite (YAP) and yttrium aluminium monoclinic (YAM) phases, expected in this system, were no detected.
|
|
|