Synthesis and crystallization of yttrium-aluminium garnet and related compounds

✍ Scribed by N. J. Hess; G. D. Maupin; L. A. Chick; D. S. Sunberg; D. E. McCreedy; T. R. Armstrong

• Publisher: Springer
• Year: 1994
• Tongue: English
• Weight: 586 KB
• Volume: 29
• Category: Article
• ISSN: 0022-2461
• DOI: 10.1007/bf00351307

✦ Synopsis

Amorphous oxide combustion products with compositions corresponding to Y4AI209, YAIO 3, and Y3AI5012 were synthesized by the glycine-nitrate process and heat-treated to induce crystallization. The crystalline structure of the resulting powders was determined by powder X-ray diffraction techniques. The phase stabilities of the crystalline phases were investigated as functions of the glycine-to-nitrate ratio, the yttrium-to-aluminium ratio, and the heat-treatment conditions. Heat treatment for short durations resulted in incompletely crystalline powders that consisted of a mixture of Y4AI209, YAlO 3, and Y3AIs012 phases, regardless of the chemical composition of the amorphous combustion product. However, heat treatment for longer durations or higher temperature generated both pure-phase, monoclinic Y4AI209 and Y3AIs012 with the garnet structure. Prolonged heat treatment at high temperature failed to generate pure-phase orthorhombic YAI03. Subsequent analysis revealed a sluggish, complex crystallization process involving the formation and decomposition of several phases.