W. Mista et al., FORMATION OF NEODYMIUM-ALUMINUM OXIDE BINARY-SYSTEM PREPARED FROM NITRATES BY COPRECIPITATING WITH AMMONIA, Polish Journal of Chemistry, 70(12), 1996, pp. 1506-1511
The phase and texture conversions in the Nd2O3-Al2O3 binary system of
variable molar composition occurring during the heat treatment at temp
eratures up to 1200 degrees C in air were studies by XRD, DTA, and the
specific surface area S-BET measurements. the samples were synthetize
d by neutralization of solutions of aluminium and neodymium nitrates w
ith ammonia. It was shown that above 460 degrees C, samples rich in Nd
, produced amorphous, non-porous materials which crystallized at 800-9
00 degrees C to give perovskite NdAlO3, and transition mixed phase Nd-
Al-O with structure of hexagonal neodymium oxide (A-Nd2O3) with the la
ttice constants (for the Al:Nd=50:50% mol content) a=4.009 Angstrom, c
=5.038 Angstrom. This phase is unstable and decomposes at 930 degrees
C to give perovskite NdAlO3. The crystallization temperatures for samp
les with low nd content are shifted towards higher temperatures.