Lead-free piezoelectric ceramic composition, the piezoelectric element, a knock sensor using the same, and a method for manufacturing a lead-free piezoelectric ceramic composition

摘要

[Object] To provide a lead-free piezoelectric ceramic composition having good piezoelectric properties without abrupt properties changes between -50°C and +150°C. [Solution] A lead-free piezoelectric ceramic composition includes a first crystal phase of alkali niobate/tantalate type perovskite oxide having piezoelectric properties and a second crystal phase of A-Ti-B-O composite oxide (where the element A is an alkali metal; the element B is at least one ofNb and Ta; and the contents of the element A, the element B and Ti are not zero). Examples of the second crystal phase are those represented by A 1- x Ti 1- x B 1+ x O 5 . It is preferable that x satisfies 0 ‰¤ x ‰¤ 0.15.