caa a22 4500 388018534 CHVBK 20180307124917.0 cr unu---uuuuu 161130e199811 xx s 000 0 eng 10.1557/JMR.1998.0425 doi S0884291400046598 pii (NATIONALLICENCE)cambridge-10.1557/JMR.1998.0425 Synthesis of BaAl2Si2O8 from solid Ba-Al-Al2O3-SiO2 precursors: Part III. The structure of BaAl2Si2O8 formed by annealing at ≤650 °C and at 1650 °C [Elektronische Daten] Analytical TEM and HREM have been used to examine the structure of BaAl2Si2O8 crystals produced within oxidized Ba-Al-Al2O3-SiO2 precursors upon annealing: (i) at ≤650 °C and (ii) up to 1650 °C. A BaAl2Si2O8 polymorph with a c-axis parameter of 15.6 Å was detected after annealing at ≤650 °C. Stacking faults and antiphase boundaries were detected within this polymorph after the 650 °C treatment. After a 15 h heat treatment at 1650 °C, convergent beam diffraction patterns and HREM confirmed that the predominant phase was β-hexacelsian. Although antiphase boundaries were absent in the β-hexacelsian crystals, dislocations and stacking faults were detected after the 1650 °C anneal. The generation of defects in BaAl2Si2O8 crystals within specimens annealed at ≤650 °C and at 1650 °C is discussed in light of prior structural analyses. Copyright © Materials Research Society 1998 Zhang Xiao-Dong Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 Sandhage Kenneth H. Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 Fraser Hamish L. Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 Journal of Materials Research Cambridge University Press 13/11(1998-11), 3122-3134 0884-2914 13:11<3122 1998 13 JMR https://doi.org/10.1557/JMR.1998.0425 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/JMR.1998.0425 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhang Xiao-Dong Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 NATIONALLICENCE 700 1- Sandhage Kenneth H. Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 NATIONALLICENCE 700 1- Fraser Hamish L. Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 NATIONALLICENCE 773 0- Journal of Materials Research Cambridge University Press 13/11(1998-11), 3122-3134 0884-2914 13:11<3122 1998 13 JMR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge