pyrochlore prepared by aqueous chemical synthesis

摘要

Pyrochlore structured Gd_2Zi_2O_7 and Nd_2Zr_2O_7 are produced via complex precipitation processing. A suite of characterization techniques, including FTIR, Raman, X-ray and electron diffraction, TEM, SEM as well as nitrogen sorption arc employed to investigate the structural and grain size evolution of the synthesized and calcined powder. Results show that Gd_2Zr_2O_7 with the pyrochlore structure arc produced after calcination at 1400 °C for 12 h while Nd_2Zr_2O_7 has already formed the pyrochlore structure at 1200 °C. This method allows the formation of dense materials at relatively low temperature, with bulk densities over 92% of the theoretical values achieved after sintering at 1400°C for 50 h. This unique aqueous synthetic method provides a simple pathway to produce pyrochlore lanthanide zirconate without using either organic solvent and/or mechanical milling procedures, making the synthesis protocol an attractive potential scale-up production of highly refractory ceramics.