Study on Pyrolysis Behavior of Yttrium Oxalate and Kinetic of Yttria Grain Grown

Abstract

The precursor of yttria was prepared by yttrium nitrate and ammonium oxalate in water solution. Pyrolysis behavior of the precursor and the characterization of yttria phase transformation were studied through thermoanalysis. The grain growth kinetic behavior of yttria nanopowders was investigated by the X-ray powder diffraction (XRD) result of the powders obtained through roasting the precursor. Pattern of the yttria powders and agglomeration of its grain were measured by means of SEM and laser particle size analysis methods. The results suggested that cubic crystal phase yttria could be obtained by sample calcination for 1 h under 823 K. When the precursor was calcined under conditions of temperature ranging from 823 K to 1173 K, yttria grain ranging 7 nm ~ 16 nm could be obtained ,with grain growth exponent of n< 0.2 . In addition , an significant increase in grain-growth-rate constant was observed as the temperature went up. The higher temperature, the faster growth. Grain growth activation energy was different in low-temperature and high-temperature fields. The activation energy was 77.42 kJ•mol-1 when the temperature was lower than 965 K, and became 524.36 kJ•mol-1 when the temperature was higher than 965 K. Yttria powders is highly dispersed whose agglomerates sized about 400 nm after being dispered in deionezed water.

Raman spectroscopy and electrical properties of polypyrrole doped dodecylbenzene sulfonic acid/Y2O3 composites

“…Moreover, Y 2 O 3 is a very essential ceramic compound that can be used as a corrosion resistance material, temperature dependent electronic devices fabrication particularly due to high thermal stability. The Y 2 O 3 plays very important role in laser host materials to enhance the life span of luminous lamps and their thermal stability [21][22]. Finally, the Y 2 O 3 owing to high surface area was utilized as a catalyst carrier [23] in order to increase the conductivity of temperature dependent electronic devices.…”