CN105541327A - Preparation method of potassium sodium niobate-based piezoelectric ceramic - Google Patents

Abstract

The invention relates to a potassium sodium niobate-based piezoelectric ceramic and a preparation method thereof. The chemical composition of the above ceramic material is KaNabNbxSbyO3, wherein a is greater than 0.2 and not greater than 0.8, b is greater than 0.2 and not greater than 0.8, x is greater than 0.6 and not greater than 1, and y is greater than 0 and not greater than 0.4. The preparation method comprises the following steps: preparing ceramic powder at a low temperature through a hydrothermal technology, adding an adhesive, granulating above materials, ageing obtained granules, dumping the aged granules, and carrying out normal pressure sintering to obtain the ceramic sample. The preparation method is simple and is convenient to operate, and ceramic chips produced in the invention have good piezoelectric performances.

Description

A kind of preparation method of potassium sodium niobate piezoelectric ceramics

Technical field

The invention belongs to environmentally friendly Material Field, a kind of potassium sodium niobate piezoelectric ceramics material and preparation method thereof is particularly provided.

Background technology

Piezoelectric ceramics is a kind of ceramic material that can realize mechanical energy and electric energy and mutually change, and is widely used in the fields such as military affairs, automobile, business and medical skill.Because leaded base piezoelectric ceramic has larger piezoelectric constant, and regulator performance can be carried out by doping vario-property and meet different application demands, so leaded base piezoelectric ceramic is still main application function pottery in the application, mainly contain Pb (Ti, Zr) O ₃(PZT), PbTiO ₃-PbZrO ₃-ABO ₃(ABO ₃for composite perofskite type ferroelectrics) and PbTiO ₃deng.But have unfriendly type because lead has toxicity to environment, because the mankind and the Nature are got along amiably and peacefully and the needs of Sustainable development, Chinese scholars starts to try to explore unleaded piezoelectric ceramics.

Niobate (KNN) leadless piezoelectric ceramics is first developmental research about the sixties in 20th century.Its chemical general formula is ABO ₃(A is K, Na; B is Nb, Ta, Sb etc.).Niobate base lead-free piezoelectric ceramic has higher Curie temperature, and mechanical quality factor and specific inductivity are all lower, and acoustic propagation velocity is larger.But the shortcoming of KNN piezoelectric ceramics, when high temperature, sintering is due to the volatilization of K, Na element, causes departing from of stoichiometric ratio, is difficult to obtain the very large ceramic body of compactness by traditional sintering method.In order to overcome the above-mentioned defect of pure KNN pottery, optimize its piezoelectric property, mainly concentrate on following two aspects: (1) component doping vario-property; (2) preparation technology and texture modifiedly to improve.

The method preparing potassium-sodium niobate based powders at present has the methods such as hydrothermal method, sol-gel method, solid reaction process, molten-salt growth method, coprecipitation method.Much traditional method is all harsher to the requirement of condition in the process of preparation, and the particle diameters generated is also larger, and solid phase method easily causes the sintering between particle to harden and grain particles is uneven greatly, thus can not reach the requirement of Nano grade.Hydrothermal method directly can prepare powder, and eliminate the pre-burning stage that conventional solid sintering process has to pass through, technique is simple.The temperature of hydro-thermal reaction is lower (about 200 DEG C, sol-gel method is usually more than 600 DEG C), so environmental protection and energy saving more.In addition, powder prepared by hydrothermal method, uniform particles, purity is high, time saving and energy saving.

Summary of the invention

In the face of prior art Problems existing, the present invention aims to provide a kind of potassium sodium niobate piezoelectric ceramics simultaneously with the simple and higher pressure electrical property of preparation technology.

The chemical constitution of a kind of potassium sodium niobate piezoelectric ceramics material provided by the invention is K _ana _bnb _xsb _yo ₃, wherein 0.2<a≤0.8,0.2<b≤0.8,0.6<x≤1,0<x≤0.4.

The present invention is according to chemical constitution, and experimental procedure is as follows:

(1) according to chemical constitution, raw material is calculated required quality separately according to molar percentage, adopts hydrothermal method, raw material is put into the reactor inner bag of tetrafluoroethylene, stir, at temperature 180-220 DEG C, insulation 20-40 hour, carries out the synthesis of niobate;

(2) suction filtration, dried powder, adds the polyvinyl alcohol granulation ageing of appropriate 5%;

(3) particle is loaded in the mould of Φ 10-20mm, compression moulding;

(4) ceramic plate dump temperature is 450-550 DEG C, binder removal time 1-8 hour;

(5) ceramic plate after binder removal is put into High Temperature Furnaces Heating Apparatus, bury burning with lapis amiridis, sintering temperature is 900-1100 DEG C, soaking time 1-4 hour;

(6) by silver-colored for potassium sodium niobate piezoelectric ceramics sheet, polarization, poling temperature is 100-200 DEG C, and the time is 10-30 minute, and voltage is 1-8kv/mm, completes polarization after 1 to 2 day, carries out performance test to ceramic plate.

The potassium sodium niobate piezoelectric ceramics tool that the present invention proposes has the following advantages:

(1) environmental friendliness shaped material, the objectionable constituent such as not leaded, environmental protection;

(2) ceramic powder preparation is simple, does not need to differentiate level of response by observing response phenomenon, easy to operate, time saving and energy saving;

(3) good piezoelectric property, piezoelectric constant d ₃₃73pC/N can be reached.

Accompanying drawing explanation

Fig. 1 is the X ray diffracting spectrum of an example stupalith of the present invention.

Fig. 2 is the electron scanning micrograph of an example stupalith of the present invention.

Embodiment

Piezoelectric ceramics sample in the present invention, takes hydrothermal method to prepare ceramic powder, normal pressure-sintered technique, its process comprise powder preparation, granulation ageing, compressing tablet, sintering, by technical process such as silver, polarization.Be specially:

(1) according to chemical constitution, raw material is calculated required quality separately according to molar percentage, adopts hydrothermal method, raw material is put into the reactor inner bag of tetrafluoroethylene, stir, at temperature 180-220 DEG C, insulation 20-40 hour, carries out the synthesis of niobate;

(2) suction filtration, dried powder, adds the polyvinyl alcohol granulation ageing of appropriate 5%;

(3) particle is loaded in the mould of Φ 10-20mm, compression moulding;

(4) ceramic plate dump temperature is 450-550 DEG C, binder removal time 1-8 hour;

(5) ceramic plate after binder removal is put into High Temperature Furnaces Heating Apparatus, bury burning with lapis amiridis, sintering temperature is 900-1100 DEG C, soaking time 1-4 hour;

(6) by silver-colored for potassium sodium niobate piezoelectric ceramics sheet, polarization, poling temperature is 100-200 DEG C, and the time is 10-30 minute, and voltage is 1-8kv/mm, completes polarization after 1 to 2 day, carries out performance test to ceramic plate.

Below in conjunction with specific embodiment, content of the present invention is described in further detail, but the invention is not restricted to the following specific examples enumerated.

Embodiment 1

(1) according to general formula K _ana _bnb _xsb _yo ₃get a=0.5, b=0.5, x=1, y=0, adopt KOH, NaOH, Nb of AR or 4N level ₂o ₃, Sb ₂o ₃for raw material, weigh by above formula stoichiometry.Adopt hydrothermal method, raw material is put into the reactor inner bag of tetrafluoroethylene, add distilled water and stir, temperature 180 DEG C, be incubated 24 hours, carry out the synthesis of niobate;

(2) suction filtration, dried powder, adds the polyvinyl alcohol granulation ageing of appropriate 5%;

(3) particle is loaded in the mould of Φ 10mm, compression moulding;

(4) ceramic plate dump temperature is 500 DEG C, 1 hour binder removal time;

(5) ceramic plate after binder removal is put into High Temperature Furnaces Heating Apparatus, bury burning with lapis amiridis, sintering temperature is 1060 DEG C, soaking time 2 hours;

(6) by silver-colored for potassium sodium niobate piezoelectric ceramics sheet, polarization, poling temperature is 120 DEG C, and the time is 15 minutes, and voltage is 3kv/mm, completes polarization after 1 day, carries out performance test to ceramic plate.

Embodiment 2

(1) according to general formula K _ana _bnb _xsb _yo ₃get a=0.5, b=0.5, x=0.96, y=0.04, adopt KOH, NaOH, Nb of AR or 4N level ₂o ₃, Sb ₂o ₃for raw material, weigh by above formula stoichiometry.Adopt hydrothermal method, raw material is put into the reactor inner bag of tetrafluoroethylene, add distilled water and stir, temperature 200 DEG C, be incubated 24 hours, carry out the synthesis of niobate;

(2) suction filtration, dried powder, adds the polyvinyl alcohol granulation ageing of appropriate 5%;

(3) particle is loaded in the mould of Φ 10mm, compression moulding;

(4) ceramic plate dump temperature is 500 DEG C, 1 hour binder removal time;

(5) ceramic plate after binder removal is put into High Temperature Furnaces Heating Apparatus, bury burning with lapis amiridis, sintering temperature is 1040 DEG C, soaking time 2 hours;

(6) by silver-colored for potassium sodium niobate piezoelectric ceramics sheet, polarization, poling temperature is 120 DEG C, and the time is 15 minutes, and voltage is 3kv/mm, completes polarization after 1 day, carries out performance test to ceramic plate.

Embodiment 3

(1) according to general formula K _ana _bnb _xsb _yo ₃get a=0.5, b=0.5, x=0.96, y=0.04, adopt KOH, NaOH, Nb of AR or 4N level ₂o ₃, Sb ₂o ₃for raw material, weigh by above formula stoichiometry.Adopt hydrothermal method, raw material is put into the reactor inner bag of tetrafluoroethylene, add distilled water and stir, temperature 200 DEG C, be incubated 24 hours, carry out the synthesis of niobate;

(2) suction filtration, dried powder, adds the polyvinyl alcohol granulation ageing of appropriate 5%;

(3) particle is loaded in the mould of Φ 10mm, compression moulding;

(4) ceramic plate dump temperature is 500 DEG C, 1 hour binder removal time;

(5) ceramic plate after binder removal is put into High Temperature Furnaces Heating Apparatus, bury burning with lapis amiridis, sintering temperature is 1080 DEG C, soaking time 4 hours;

(6) by silver-colored for potassium sodium niobate piezoelectric ceramics sheet, polarization, poling temperature is 120 DEG C, and the time is 15 minutes, and voltage is 3kv/mm, completes polarization after 1 day, carries out performance test to ceramic plate.

Embodiment 4

(1) according to general formula K _ana _bnb _xsb _yo ₃get a=0.46, b=0.54, x=0.93, y=0.07, adopt KOH, NaOH, Nb of AR or 4N level ₂o ₃, Sb ₂o ₃for raw material, weigh by above formula stoichiometry.Adopt hydrothermal method, raw material is put into the reactor inner bag of tetrafluoroethylene, add distilled water and stir, temperature 200 DEG C, be incubated 24 hours, carry out the synthesis of niobate;

(2) suction filtration, dried powder, adds the polyvinyl alcohol granulation ageing of appropriate 5%;

(3) particle is loaded in the mould of Φ 10mm, compression moulding;

(4) ceramic plate dump temperature is 500 DEG C, 1 hour binder removal time;

(5) ceramic plate after binder removal is put into High Temperature Furnaces Heating Apparatus, bury burning with lapis amiridis, sintering temperature is 1060 DEG C, soaking time 2 hours;

(6) by silver-colored for potassium sodium niobate piezoelectric ceramics sheet, polarization, poling temperature is 120 DEG C, and the time is 15 minutes, and voltage is 3kv/mm, completes polarization after 1 day, carries out performance test to ceramic plate;

Fig. 1 is its X ray diffracting spectrum, and Fig. 2 is its stereoscan photograph.

Sintering temperature 1060 DEG C, soaking time 2 hours, according to general formula K _ana _bnb _xsb _yo ₃get a=0.46, b=0.54, x=0.96, y=0.04, the optimum d of ceramic performance of preparation ₃₃reach 73pC/N, density is 4.39g/cm ².

Claims (4)

1. a potassium sodium niobate piezoelectric ceramics material, is characterized in that, the chemical constitution of described stupalith is K _ana _bnb _xsb _yo ₃, wherein 0.2<a≤0.8,0.2<b≤0.8,0.6≤x≤1,0≤y≤0.4.

2. sodium potassium niobate base leadless piezoelectric ceramics material according to claim 1, is characterized in that, 0.4<a≤0.6,0.4<b≤0.6.

3. sodium potassium niobate base leadless piezoelectric ceramics material according to claim 1, is characterized in that, 0.8≤x≤1,0≤x≤0.2.

4. prepare a method for the potassium sodium niobate piezoelectric ceramics described in claims 1 to 3, concrete steps are as follows:

(1) according to chemical constitution, raw material is calculated required quality separately according to molar percentage, adopts hydrothermal method, raw material is put into the reactor inner bag of tetrafluoroethylene, stir, at temperature 180-220 DEG C, insulation 20-40 hour, carries out the synthesis of niobate;

(2) suction filtration, dried powder, adds the polyvinyl alcohol granulation ageing of appropriate 5%;

(3) particle is loaded in the mould of Φ 10-20mm, compression moulding;

(4) ceramic plate dump temperature is 450-550 DEG C, binder removal time 1-8 hour;

(5) ceramic plate after binder removal is put into High Temperature Furnaces Heating Apparatus, bury burning with lapis amiridis, sintering temperature is 900-1100 DEG C, soaking time 1-4 hour;

(6) by silver-colored for potassium sodium niobate piezoelectric ceramics sheet, polarization, poling temperature is 100-200 DEG C, and the time is 10-30 minute, and voltage is 1-8kv/mm, completes polarization after 1 to 2 day, carries out performance test to ceramic plate.