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:
Feb. 24, 2009
Filed:
Feb. 28, 2006
Xiaoxing Wang, Hung Hom Kowloon, HK;
Kin Wing Kwok, Hung Hom Kowloon, HK;
Helen Lai Wah Chan, Hung Hom Kowloon, HK;
Siu Hong Choy, Hung Hom Kowloon, HK;
Xiaoxing Wang, Hung Hom Kowloon, HK;
Kin Wing Kwok, Hung Hom Kowloon, HK;
Helen Lai Wah Chan, Hung Hom Kowloon, HK;
Siu Hong Choy, Hung Hom Kowloon, HK;
The Hong Kong Polytechnic University, Hung Hom Kowloon, HK;
Abstract
The present invention provides a piezoelectric ceramic composition, especially a lead-free piezoelectric ceramic composition, with a suitable amount of CeOor CeO-containing complex additives, which is represented by the following formula: (NaKLi)(NbA)O+yCeO+zBOwherein 'A' represents Sb or Sb+Ta, 'B' represents a tetravalent transition metal, 0≦x≦0.2, 0.2 wt %<y<1.2 wt % and 0≦z 1 wt %. Addition of CeOor CeO-containing complex additives suppresses melting and abnormal grain growth of (NaKLi)(NbA)Oduring sintering, thereby improving sinterability and increasing the density of the composition. As a result, the dielectric and piezoelectric properties of the ceramics are enhanced. Furthermore, the represented compositions have a wide sintering temperature range so that the process for preparing such a lead-free piezoelectric ceramic composition has high degree efficiency.