Piezoelectric ceramic stacked structure
AssigneeKorea Atomic Energy Research Institute
InventorsMin Ku LEE, Kyu Hyun PARK, Gyoung Ja LEE, Byung Hoon KIM, Jin Ju PARK
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Abstract
The present invention relates to a piezoelectric ceramic stacked structure, and the piezoelectric ceramic stacked structure includes at least one first layer including a KNN-based ceramic; and at least one second layer including a BFO-based ceramic, wherein a ratio of a number (n1) of the first layers stacked to a number (n2) of the second layers stacked in the piezoelectric ceramic stacked structure satisfies Equation (1) below: 0.8×|q|/|p|≤n1/n2≤1.2×|q|/|p| (1) (Equation (1) is as defined in the Description).
Claims20
A piezoelectric ceramic stacked structure, comprising:
- at least one first layer comprising a KNN-based ceramic;
- and
- at least one second layer comprising a BFO-based ceramic,
- wherein a ratio of a number (n1) of the first layers stacked to a number (n2) of the second layers stacked in the piezoelectric ceramic stacked structure satisfies Equation (1) below:
- 0.8×|q|/|p|≤n1/n2≤1.2×|q|/|p| (1)
- in Equation (1), |p| represents an absolute value of a decrease rate (p) of a charge sensitivity according to a temperature of the first layer, and |q| represents an absolute value of an increase rate (q) of a charge sensitivity according to a temperature of the second layer, and
- the decrease rate (p) of the charge sensitivity according to the temperature of the first layer and the increase rate (q) of the charge sensitivity according to the temperature of the second layer are slope values of a straight line obtained by approximating the charge sensitivity according to the temperature within a temperature range from room temperature (25° C.) to a Curie temperature (Tc) of the KNN-based ceramic by a method of least squares.
A method for manufacturing a piezoelectric ceramic stacked structure, comprising:
- forming a precursor powder of a KNN-based ceramic by calcining a KNN-based precursor mixture comprising sodium precursor powder, potassium precursor powder, and niobium precursor powder;
- forming a precursor powder of a BFO-based ceramic by calcining a BFO-based precursor mixture comprising bismuth precursor powder, iron precursor powder, barium precursor powder, and titanium precursor powder;
- forming at least one first layer by sintering the precursor powder of the KNN-based ceramic;
- forming at least one second layer by sintering the precursor powder of the BFO-based ceramic;
- and
- forming a stacked structure including n1 of the first layers and n2 of the second layers
- wherein a ratio of a number (n1) of the first layers stacked to a number (n2) of the second layers stacked satisfies Equation (1) below:
- 0.8×|q|/|p|≤n1/n2≤1.2×|q|/|p| (1)
- in Equation (1), |p| represents an absolute value of a decrease rate (p) of a charge sensitivity according to a temperature of the first layer, and |q| represents an absolute value of an increase rate (q) of a charge sensitivity according to a temperature of the second layer, and
- the decrease rate (p) of the charge sensitivity according to the temperature of the first layer and the increase rate (q) of the charge sensitivity according to the temperature of the second layer are slope values of a straight line obtained by approximating the charge sensitivity according to the temperature within a temperature range from room temperature (25° C.) to a Curie temperature (Tc) of the KNN-based ceramic by a method of least squares.
Dependencies are inferred from the claim text.