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US 6,207,070 B1Granted
Composition for piezoelectric ceramics
AssigneeTDK Corporation
InventorsSatoshi Sasaki, Masaru Abe
Life of this patent
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Abstract
Composition for piezoelectric ceramics includes a main component and a sub component. The main component is expressed with a general expression of aPb(Mg⅓Nb⅔)O3-bPb(Yb⅓Nb⅔)O3-cPbTiO3-dPbZrO3, where a+b+c+d=1, 0.01≦a≦0.07, 0.01≦b≦0.07, 0.35≦c≦0.55, and 0.4≦d≦0.6. The sub component contains 0.1 to 0.7 wt % of Mn in terms of manganese oxide, 0.01 to 0.3 wt % of Cr in terms of chromium oxide and 0.05 to 0.5 wt % of Co in terms of cobalt oxide per the weight of 1 mol of main component.
Claims9
A piezoelectric ceramic composition comprising:
- a main component expressed with a general expression of aPb(Mg⅓Nb⅔)O3-bPb(Yb⅓Nb⅔)O3-cPbTiO3-dPbZrO3, where a+b+c+d=1, 0.01≦a≦0.07, 0.01≦b≦0.07, 0.35≦c≦0.55, 0.4≦d≦0.6;
- and
- a subcomponent containing 0.1 to 0.7 wt % of Mn in terms of manganese oxide, 0.01 to 0.3 wt % of Cr in terms of chromium oxide and 0.05 to 0.5 wt % of Co in terms of cobalt oxide per the weight of 1 mol of main component, wherein
- the composition has an electromechanical coupling coefficient (kt)≧40.0%. a coefficient of mechanical quality (Qm)≧500, a rate of change of kt after heat resistance test is within the range of −2.0% to 2.0% and a rate of change of kt after thermal shock test is within the range of −2.0% to 2.0%.
1 more element
Dependencies are inferred from the claim text.