Preparation of Barium Titanate–Potassium Niobate Nanostructured Ceramics with Artificial Morphotropic Phase Boundary Structure By Solvothermal Method

2011 ◽  
Vol 50 (9) ◽  
pp. 09NC08 ◽  
Author(s):  
Satoshi Wada ◽  
Shigehito Shimizu ◽  
Kenta Yamashita ◽  
Ichiro Fujii ◽  
Kouichi Nakashima ◽  
...  
Keyword(s):  
Barium Titanate ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Solvothermal Method ◽  
Boundary Structure ◽  
Potassium Niobate ◽  
Nanostructured Ceramics

Piezoelectric and Dielectric Enhancement of New Nano-structured Ceramics with Heteroepitaxial Interfaces

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000001-000004
Author(s):  
Satoshi Wada ◽  
Kenta Yamashita ◽  
Hideto Kawashima ◽  
Ichiro Fujii ◽  
Shintaro Ueno ◽  
...  
Keyword(s):  
Barium Titanate ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Solvothermal Method ◽  
Piezoelectric Ceramics ◽  
Piezoelectric Constant ◽  
Molar Ratio ◽  
Potassium Niobate ◽  
Composite Ceramics ◽  
Dielectric Enhancement

Barium titanate (BT) - potassium niobate (KN) nano-structured ceramics with an artificial morphotropic phase boundary (MPB) structure were prepared by a solvothermal method at temperatures below 230 °C. Various characterizations of the BT-KN nano-structured ceramics revealed that the BT/KN molar ratio was 1, the porosity was around 30 %, and the interface between BT particles and KN crystals was heteroepitaxial. The apparent piezoelectric constant d33* was 136 pC/N, which was three times larger than that of 0.5BT-0.5KN dense composite ceramics. The concept proposed in this study can be useful to create piezoelectric ceramics with artificial MPB regions.

Preparation of Potassium Niobate-Coated Barium Titanate Accumulation Ceramics by Solvothermal Synthesis and Enhancement of Piezoelectric Property

2013 ◽  
Vol 566 ◽  
pp. 76-80 ◽  
Author(s):  
Kenta Yamashita ◽  
Shigehito Shimizu ◽  
Nobuhiro Kumada ◽  
Kouichi Nakashima ◽  
Ichiro Fujii ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Piezoelectric Property ◽  
Solvothermal Synthesis ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Solvothermal Method ◽  
Potassium Niobate ◽  
Nanostructured Ceramics ◽  
Dielectric And Piezoelectric Properties

Barium titanate (BaTiO3, BT) - potassium niobate (KNbO3, KN) nanostructured ceramics with artificial morphotropic phase boundary (MPB) structure were successfully prepared at temperatures below 230 °C by solvothermal method. Various characterizations suggested that the BT-KN nanostructured ceramics exhibited a porosity of around 30 % and heteroepitaxial interface between BT and KN. Their dielectric and piezoelectric properties were measured at room temperature, and the dielectric constant and apparent piezoelectric constant estimated from slope of strain and electric field curve was 370 and 136 pm/V, respectively.

Phase Diagram and Microstructure Analysis of Barium Titanate – Potassium Niobate System Piezoelectric Ceramics

2009 ◽  
Vol 421-422 ◽  
pp. 34-37 ◽  
Author(s):  
Satoshi Wada ◽  
Momoyo Nitta ◽  
Nobuhiro Kumada ◽  
Daisuke Tanaka ◽  
Masahito Furakawa ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Barium Titanate ◽  
Phase Boundary ◽  
Wide Band ◽  
Dielectric Measurement ◽  
Potassium Niobate ◽  
Sintering Process ◽  
Transmission Electron ◽  
High Temperature Xrd ◽  
Two Phases

Barium titanate (BaTiO3, BT) and potassium niobate (KNbO3, KN) ceramics were prepared by normal sintering process. Phase diagram of BT-KN system was investigated using high-temperature XRD and dielectric measurement, and two phases coexistence between tetragonal and orthorhombic was observed at room temperature. Transmission electron microscope (TEM) observation confirmed that the microstructure of the ceramics with KN contents below 30 molar% was composed of only tetragonal BT-rich grain, while those with KN contents above 40 molar% were composed of two kinds of grains, i.e., tetragonal BT-rich and orthorhombic KN-rich grains. Phase boundary between two phases for BT-KN ceramics was grain boundary. Thus, we named two phases coexistence region for BT-KN ceramics “wide-band morphotropic phase boundary (MPB)”. Finally, dielectric and piezoelectric properties were investigated, and both dielectric and apparent d33 maximum were observed at the 0.5BT-0.5KN ceramics.

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