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Thermochemical Reactions Between PZT and Ag/Pd Powders: Relevance to Cofiring of Multilayer Actuators
Author(s) -
Donnelly Niall J.,
Shrout Thomas R.,
Randall Clive A.,
Reaney Ian M.
Publication year - 2008
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.1551-2916.2007.02230.x
Subject(s) - materials science , crystallite , transmission electron microscopy , ceramic , scanning electron microscope , phase (matter) , decomposition , electrode , analytical chemistry (journal) , thermal decomposition , chemical engineering , composite material , metallurgy , nanotechnology , chemistry , organic chemistry , chromatography , engineering
Mixtures of Ag 1− x Pd x ( x =0.2, 0.3) and doped PZT ceramic powders have been heat treated in air and the resulting phase content has been analyzed by X‐ray diffraction and transmission electron microscopy. Beginning around 400°C, a phase similar to PbPdO 2 is formed on the surface of the Ag 1− x Pd x particles and subsequently decomposes at temperatures <700°C. Consequently, the remaining Ag 1− x Pd x powder becomes significantly silver‐rich while the reaction progresses. After decomposition the Pd appears to realloy and the initial Ag 1− x Pd x composition is recovered. We show that the reaction is all but eliminated in a nitrogen atmosphere. The occurrence of this reaction was also investigated in PZT multilayer actuators cofired with Ag 0.7 Pd 0.3 electrodes. Transmission electron microscope analysis revealed the presence of distinct crystallites at the electrode–ceramic interface, most likely nucleated from a PbO liquid phase arising from the decomposition of PbPdO 2 .