Synthesis of sinteractive single-phase microstructure yttrium disilicate precursor powder using hydrothermal processing

• Published in: Journal of materials research Vol. 13; no. 11; pp. 3135 - 3143
• Main Authors: Trusty, P. A., Chan, K. C., Ponton, C. B.
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.11.1998
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/JMR.1998.0426

This paper is the first report of the synthesis of a sinteractive single-phase microstructure yttrium disilicate precursor powder using hydrothermal processing. The effect of the pH of the precursor chemicals on the ease of formation of a single-phase material was investigated using x-ray diffraction, TEM, and SEM. Under very acidic conditions (pH 1), the formation of yttrium chloride, in addition to the yttrium disilicate precursors, produced a powder that absorbed moisture, did not sinter well, and produced a two-phase interpenetrating microstructure after sintering. At pH 6, yttrium chloride no longer formed, but the interpenetrating network persisted after sintering. Only under basic conditions (pH 10) did single-phase yttrium disilicate form after sintering. This work is noteworthy because the calcination time of 1 h required for the formation of this ceramic at 1050 °C is over an order of magnitude lower than the calcination times of over 100 h required when calcined in the temperature range 900 °C to 1150 °C, as reported previously by other workers.