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Hydrothermal Synthesis of Ferroelectric Mixed Potassium Niobate–Lead Titanate Nanoparticles
Author(s) -
Delahaye Thierry,
AlZein Ali,
Berger MarieHélène,
Bril Xavier,
Hochepied JeanFrançois
Publication year - 2014
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/jace.12778
Subject(s) - materials science , potassium niobate , ferroelectricity , grain size , hydrothermal circulation , dielectric , mineralogy , chemical engineering , nanoparticle , hydrothermal synthesis , ceramic , perovskite (structure) , crystallite , lead titanate , analytical chemistry (journal) , nanotechnology , composite material , metallurgy , chemistry , chromatography , optoelectronics , engineering
Potassium niobate–lead titanate solid‐solution nanoparticles have been synthesized using a new hydrothermal method. The key step is an in situ acid–base exothermic reaction with a large excess of KOH , generating an amorphous precipitated gel. This gel, when crystallized in an autoclave for 2 h at 190°C, produces a mixed perovskite solid solution with [ KNbO 3 ] 0.8 –[ PbTiO 3 ] 0.2 ( KNPT ) composition, and parallelepiped particles rang in size from a few tens to a few hundreds of nanometer in length. This study proves that the pure perovskite phase can be obtained in spite of the different solubilities of the reactive cations in an ethanol–water solution. Dielectric measurements show that KNPT ceramic with a grain size of 50 nm is ferroelectric at room temperature. In addition, ceramics sintered at 950°C have an average grain size of 500 nm, and exhibit a maximum permittivity of 2100 at 1 kHz near T C = 510 K and a remanent polarization P r = 12 μC/cm 2