Premium
Single‐Calcination Synthesis of Pyrochlore‐Free 0.9Pb(Mg 1/3 Nb 2/3 )O 3 –0.1PbTiO 3 and Pb(Mg 1/3 Nb 2/3 )O 3 Ceramics Using a Coating Method
Author(s) -
Gu Huiming,
Shih Wan Y.,
Shih WeiHeng
Publication year - 2003
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.1151-2916.2003.tb00002.x
Subject(s) - pyrochlore , calcination , materials science , columbite , perovskite (structure) , analytical chemistry (journal) , dielectric , coating , solid solution , mineralogy , nuclear chemistry , phase (matter) , ceramic , inorganic chemistry , crystallography , metallurgy , catalysis , chemistry , chromatography , nanotechnology , biochemistry , optoelectronics , organic chemistry
A coating approach for synthesizing 0.9Pb(Mg 1/3 Nb 2/3 )O 3 –0.1PbTiO 3 (0.9PMN–0.1PT) and PMN using a single calcination step was demonstrated. The pyrochlore phase was prevented by coating Mg(OH) 2 on Nb 2 O 5 particles. Coating of Mg(OH) 2 on Nb 2 O 5 was done by precipitating Mg(OH) 2 in an aqueous Nb 2 O 5 suspension at pH 10. The coating was confirmed using optical micrographs and zeta‐potential measurements. A single calcination treatment of the Mg(OH) 2 ‐coated Nb 2 O 5 particles mixed with appropriate amounts of PbO and PbTiO 3 powders at 900°C for 2 h produced pyrochlore‐free perovskite 0.9PMN–0.1PT and PMN powders. The elimination of the pyrochlore phase was attributed to the separation of PbO and Nb 2 O 5 by the Mg(OH) 2 coating. The Mg(OH) 2 coating on the Nb 2 O 5 improved the mixing of Mg(OH) 2 and Nb 2 O 5 and decreased the temperature for complete columbite conversion to ∼850°C. The pyrochlore‐free perovskite 0.9PMN–0.1PT powders were sintered to 97% density at 1150°C. The sintered 0.9PMN–0.1PT ceramics exhibited a dielectric constant maximum of ∼24 660 at 45°C at a frequency of 1 kHz.