Leadless piezoelectric ceramics

A lead-free piezoelectric and ceramic technology, applied in the field of piezoelectric ceramics, can solve problems such as the temperature limit of BNT application, and achieve the effects of increasing depolarization temperature, good high-temperature ferroelectricity, and low raw material cost

Inactive Publication Date: 2009-10-21
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

A significant disadvantage of BNT-based ceramics is that there is a ferroelectric-antiferroelectric phase transition point at around 160°C, called the depolarization temperature, which limits the application temperature of BNT.

Method used

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  • Leadless piezoelectric ceramics
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  • Leadless piezoelectric ceramics

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] For formula (1-x) Bi 0.5 Na 0.5 TiO 3 -xBi 0.8 La 0.2 FeO 3 , x=0.0125.

[0022] performance:

[0023] piezoelectric coefficient

Embodiment 2

[0025] For formula (1-x) Bi 0.5 Na 0.5 TiO 3 -xBi 0.8 La 0.2 FeO 3 , x=0.0375.

[0026] performance:

[0027] piezoelectric coefficient

Embodiment 3

[0029] For formula (1-x) Bi 0.5 Na 0.5 TiO 3 -xBi 0.8 La 0.2 FeO 3 , x=0.0625.

[0030] performance:

[0031] piezoelectric coefficient

d 33 (pC / N)

electromechanical coupling

Coefficient k p

depolarization temperature

T d (℃)

Saturation polarization Ps

(μC / cm 2 )

remanent polarization P r

(μC / cm 2 )

coercive field E c

(kV / mm)

X＝0.0625

20

0.027

171

28

11

5.5

[0032] figure 1 is (1-x) Bi 0.5 Na 0.5 TiO 3 -xBi 0.8 La 0.2 FeO 3 (Where 0.0125≤x≤0.0625) The X-ray diffraction spectrum (XRD) of ceramics, it shows that the sample prepared under this condition is a single phase without other impurity phases. And, from the XRD spectra of these ceramics, it can be obtained that when x=0.0125, the ceramics have a trigonal-orthorhombic quasi-isomorphic phase boundary structure.

[0033] Figure 2a , 2b is (1-x) Bi 0.5Na 0.5 TiO 3 -xBi 0.8 La 0.2 FeO 3 (where 0.01...

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PUM

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Abstract

The invention discloses leadless piezoelectric ceramics, the chemical formula thereof is (1-x)Bi0.5Na0.5TiO3-xBi0.8La0.2FeO3, wherein x is more than or equal to 0.0125 and is less than or equal to 0.0625; the invention replaces Bi0.5Na0.5TiO3 with introduced Bi0.8La0.2FeO3 so as to form tripartite-orthogonal morphotropic phase boundary structure which has leadless piezoelectric ceramics composition point with excellent high temperature ferroelectric and piezoelectric property, thereby increasing the depolarization temperature of the ceramics to a certain degree; the piezoelectric modulus d33 and the electromechanical coupling factor kp decrease with increasing parameter x, d33 varies from 20pC/N to 128pC/N, and kp varies from 0.27 to 0.30; the saturation polarization, residual polarization and coercive field of the ceramics decrease with increasing parameter x; in particular, the depolarization temperature of the ceramics (Td) increases between 163 DEG C and 171 DEG C with increasing x.

Description

technical field [0001] The invention relates to a piezoelectric ceramic, in particular to a lead-free piezoelectric ceramic. Background technique [0002] In high-tech fields such as information, laser, and navigation, piezoelectric materials, as an important class of applied functional materials, have been widely used. ABO-based 3 Pb(Zr 1-x Ti x )O 3 Ceramics have excellent piezoelectric properties and are piezoelectric materials that have been widely used in industry. However, since such materials contain lead, the toxicity of lead will cause serious harm to the human body and the natural environment after the production, use and disposal of the product, which is contrary to the sustainable development strategy. Therefore, the trend of industrial applications must be to use lead-free piezoelectric ceramics to replace the current lead-containing piezoelectric ceramics, which means that the development and research of lead-free piezoelectric ceramics with excellent piez...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/462H01L41/187
Inventor 王磊丁潞奕基维静张善涛陈延峰
Owner NANJING UNIV
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