Premium
Preparation of Metal Ruthenates by Spray Pyrolysis
Author(s) -
Senzaki Yoshihide,
HampdenSmith Mark J.,
Kodas Toivo T.,
Hussler John W.
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb09073.x
Subject(s) - pyrochlore , crystallite , materials science , oxide , metal , pyrolysis , perovskite (structure) , chemical engineering , particle size , inorganic chemistry , mineralogy , crystallography , chemistry , metallurgy , organic chemistry , engineering , phase (matter)
Submicrometer crystalline metal ruthenate powders with perovskite structure, MRuO 3 (M = Sr, La), and pyrochlore structure, M 2 Ru 2 O 7‐ x (0.5 < x < 1; M = Bi, Pb, Y, Eu, Gd, Tb, Dy, Ho, Er, Tm), were prepared by spray pyrolysis using metal nitrates and glycolates under an oxygen‐gas atmosphere at temperatures up to 1100°C. Submicrometer‐sized solid single crystals (SrRuO 3 ), submicrometer‐sized hollow spheres consisting of nanocrystallites (pyrochlore rare‐earth ruthenates, Bi 2 Ru 2 O 7 , and Pb 2 Ru 2 O 6.5 below 1000°C), and nanometer‐sized particles (Pb 2.31 Ru 1.69 O 6.5 and Bi‐Pb‐O above 1000°C) were observed. Particle formation proceeded by intraparticle reaction and intraparticle reaction followed by evaporation of volatile metal oxides to form metal oxide vapors followed by condensation and reaction to form particles. The former was observed for systems where no volatile metal oxides were formed, whereas the latter occurred for the Pb‐Ru‐O and Bi‐Ru‐O systems, where volatile metal oxides, such as Bi 2 O, PbO, and RuO x could occur. Particle morphology depended strongly on precursor properties. Submicrometer‐sized single‐crystal SrRuO 3 particles could be formed from the metal nitrates but not from Sr(NO 3 ) 2 and ruthenium glycolate, which gave hollow polycrystalline particles. In general, crystallite size could be controlled by varying precursor properties and reactor temperature, with higher temperatures giving larger crystallite sizes.