Interaction of Cerium Oxide with Hafnium, Zirconium, and Yttrium Oxides at 1500 degree C

• Published in: Powder metallurgy and metal ceramics Vol. 40; no. 7-8; pp. 405 - 413
• Main Authors: Lopato, Lidiya M, Andrievskaya, Elena R
• Format: Journal Article
• Language: English
• Published: 01.07.2001
• Subjects: Hafnium; Hafnium oxide; Phase relationships; Solid solutions; Ternary systems; Yttrium oxide; Zirconium; Zirconium dioxide
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1023/A:1013731223261

Using the methods of x-ray diffraction and petrographic analysis as well as electron microscopy, phase relationships in the ternary systems ZrO sub(2) - Y sub(2)O sub(3) - CeO sub(2) and HfO sub(2) - Y sub(2)O sub(3) - CeO sub(2) were investigated over the entire range of concentrations at 1500 degree C. The accuracy of the phase relationships of the binary systems HfO sub(2) - CeO sub(2), ZrO sub(2) - CeO sub(2), and CeO sub(2) - Y sub(2)O sub(3) at this temperature was improved. Isothermal sections of the ternary phase diagrams at 1500 degree C were constructed. Specimens of various compositions were prepared from nitrate solutions by evaporating, drying, and heat treating at 1500 degree C. These systems are characterized by the formation of broad ranges of solid solutions based on C-Y sub(2)O sub(3), F-CeO sub(2), F-HfO sub(2) and ZrO sub(2), and narrow ranges based on T-ZrO sub(2) and M-HfO sub(2). No new phases were detected. The course of isoparametric lines in the solid solution ranges of F-HfO sub(2) (ZrO sub(2)) leads to the assumption that yttrium and cerium ions substitute for each other, but no appreciable substitution by them for zirconium or hafnium ions occurs.