High temperature, high strain piezoelectric compositions
US6279878A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 2000 |
| Grant date | Aug 28, 2001 |
| Priority date | — |
| Expiry date | Apr 28, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/493
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
PLZT piezoelectric ceramics having the general formula (Pb.sub.1-x La.sub.x)(Zr.sub.y Ti.sub.1-y).sub.1-(x/4)-z M.sup.a+.sub.4z/a O.sub.3 are fabricated in a hot forging process using PbO, TiO.sub.2, ZrO.sub.2, and La.sub.2 O.sub.3 powders with Nb.sub.2 O.sub.5 and Ta.sub.2 O.sub.5 added to provide 2.0-3.0% Nb.sup.5+ (mole %) and 2.0-3.0% Ta.sup.+5 (mole %) as a dopant. ZrO.sub.2 and TiO.sub.2 powders are mixed at a molar ratio of y/(1-y), the preferred molar ratio being 55/45, calcined at approximately 1300.degree. C.-1500.degree. C., ball milled in acetone, and evaporated to a dry powder. The mixture of ZrO.sub.2 and TiO.sub.2 is then combined with PbO.sub.2, La.sub.2 O.sub.3, Nb.sub.2 O.sub.5 and Ta.sub.2 O.sub.5 powders, and the new mixture is ball milled in acetone, evaporated to a dry powder, calcined at approximately 700.degree.-850.degree. C., and sifted to obtain a particle size of approximately 0.5-1.5 .mu.m. The final Nb/Ta-doped PLZT powder is formed into the desired shape by cold pressing followed by sintering at approximately 1000.degree. C.-1150.degree. C. in oxygen. The PLZT ceramic material is further densified to about 98.5% of the material's theoretical maximum d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.