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Study of the Decomposition of Colloidal Mixed Rare Earth Hydroxycarbonate Spheres by conventional thermal treatment and by electron‐beam irradiation within a high‐resolution microscope
Author(s) -
Kang Z. C.,
McKelvy M. J.,
Eyring L.
Publication year - 1992
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19926161019
Subject(s) - decomposition , thermal decomposition , thermogravimetric analysis , oxide , materials science , scanning electron microscope , colloid , differential thermal analysis , spheres , analytical chemistry (journal) , chemical engineering , mineralogy , diffraction , chemistry , optics , composite material , metallurgy , chromatography , organic chemistry , physics , astronomy , engineering
The practical utility of colloidal particles in the processing of ceramic oxide materials demands an understanding of the decomposition of precursor compounds as they transform to the oxide. In this exposition, the transformation of mixed rare earth hydroxycarbonate colloidal spheres to the oxide is studied. Three methods are described. In one the spheres are heated in a combined thermogravimetric and differential thermal analysis system up to 1100°C. Then successive reruns were made with specimens being cooled rapidly from the temperatures where intermediate or final reaction products are formed. X‐ray diffraction patterns were taken and HREM studies were made of each sample thus produced. A second series of experiments was made in which the spheres were slowly heated to 500°C in the specimen chamber of a mass spectrometer. The gaseous decomposition products were monitored continuously. The third series involved observation of the decomposition of the colloidal spheres directly in the electron microscope. The electron‐beam‐induced decomposition to the oxide was followed at high resolution. The results of these three decomposition studies are compared and contrasted.