Templated Grain Growth of Single Crystal-Like Electroceramics
Abstract
Fiber textured bismuth titanate (Bi4Ti3O12) (BIT) and biaxially textured La-doped Sr2Nb2O7 (SN) were produced by templated grain growth. Platelets of BIT and blade-shaped SN template particles were dispersed in a matrix of nanosize BIT and fine SN powders, respectively. and aligned by tape casting. As determined by x-ray diffraction and microscopy. the sintered ceramics were >90% textured. Growth of the template particles depends critically on the presence of a liquid during growth and maintaining a template to matrix grain size ratio >2. Textured Nb-doped bismuth titanate ceramics (Bi4Ti(3-x/5)Nb(x/5)O12. where x=0.02) showed anisotropic dielectric and piezoelectric properties when measured parallel and perpendicular to the texture axes with the remanent polarization differing by more than a factor of 15 in the two directions. The piezoelectric constant in the grain-axis was 30 pC/N. or ^77% of the single crystal value. High temperature piezo, doped bismuth titanate. A gated doctor blade was developed to achieve biaxial alignment of the blade-shaped Sr2Nb2O7 template particles. Very good orientation was achieved perpendicular to the major blade axis In addition, X-ray diffraction measurements of the 131 pole revealed that the Sr2Nb2O7 was biaxially textured and had a full width at half maximum of the peak height of 30 deg in the orientation distribution in the plane of the blades.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2001
- Accession Number
- ADA386724
Entities
People
- Gary L. Messing
- Susan Trolier-McKinstry
Organizations
- Pennsylvania State University