The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 26, 2002
Filed:
Mar. 01, 2001
Toshiyuki Miyoshi, Omihachiman, JP;
Abstract
An oxide having a perovskite structure, for example, barium titanate, is provided in which the particle diameter is as small as about 0.03 to 0.2 &mgr;m, the amount of OH groups in the crystal lattice is less than about 0.2% by weight, the c/a axial ratio is as large as about 1.0033 or more and sufficient ferroelectricity is exhibited. Barium titanate is produced with steps of mixing a BaCO powder and a TiO powder having a specific surface area of about 10 m /g or more and heat-treating the mixed powder. In the heat treatment, in the case in which a partial pressure of oxygen is decreased to about 2×10 Pa or less and more than about 2×10 Pa, the heat treatment is performed at a temperature within the range of about 700 to 1100° C., and in the case in which a partial pressure of oxygen is decreased to about 2×10 Pa or less, the heat treatment is performed at a temperature within the range of about 600 to 1100° C.