阅读说明：本技术 一种无铅压电陶瓷材料的制备方法 (Preparation method of lead-free piezoelectric ceramic material ) 是由 田德辉 王宝 朱军吉 汪春权 于 2020-11-25 设计创作，主要内容包括：本发明提供一种无铅压电陶瓷材料的制备方法,包括以下步骤：(1)配料：按如下重量百分比的原料选料配比：碳酸钡BaCO3：67～68%、钛白粉TiO2：29～30%、稀土：3～3.1%；(2)混料：使用球磨机加入去离子水将各种原材料磨成粒径为1～3um的一次浆料；(3)烘干；(4)破碎；(5)预烧；(6)二次球磨；(7)离心造粒：在所述二次浆料中加入粘合剂并配以搅拌,将搅拌后的二次浆料送入喷雾塔内并控制其温度,进行喷雾造粒；(8)成型；(9)排塑；(10)烧结。通过本发明,以解决现有技术存在的压电陶瓷材料中含有铅金属,重金属污染的问题。(The invention provides a preparation method of a lead-free piezoelectric ceramic material, which comprises the following steps: (1) preparing materials: the raw materials are selected according to the following weight percentage: barium carbonate BaCO 3: 67-68% of titanium dioxide TiO 2: 29-30% and rare earth: 3-3.1%; (2) mixing materials: adding deionized water into a ball mill to grind various raw materials into primary slurry with the particle size of 1-3 um; (3) drying; (4) crushing; (5) pre-burning; (6) performing secondary ball milling; (7) and (3) centrifugal granulation: adding an adhesive into the secondary slurry, stirring, feeding the stirred secondary slurry into a spray tower, controlling the temperature of the secondary slurry, and performing spray granulation; (8) molding; (9) plastic removal; (10) and (5) sintering. The invention solves the problems that the piezoelectric ceramic material in the prior art contains lead metal and is polluted by heavy metal.)

1. A preparation method of a lead-free piezoelectric ceramic material is characterized by comprising the following steps: the method comprises the following steps:

(1) preparing materials: the raw materials are selected according to the following weight percentage: barium carbonate BaCO 3: 67-68% of titanium dioxide TiO 2: 29-30% and rare earth: 3-3.1%;

(2) mixing materials: adding deionized water into a ball mill to grind various raw materials into primary slurry with the particle size of 1-3 um;

(3) drying: putting the primary slurry into a constant-temperature circulating oven, and evaporating water into a material block;

(4) crushing: crushing the dried material blocks, and sieving the crushed material blocks by a 20-mesh sieve;

(5) pre-burning: pre-burning the material blocks at 1250 ℃ for 3-5 h;

(6) secondary ball milling: adding deionized water into the pre-sintered material blocks by using a ball mill, grinding the material blocks into slurry with the particle size of 1-3 um, and putting the slurry into a sand mill to grind into secondary slurry with the particle size of 0.5-8 um;

(7) and (3) centrifugal granulation: adding an adhesive into the secondary slurry, stirring, feeding the stirred secondary slurry into a spray tower, controlling the temperature of the secondary slurry, and performing spray granulation;

(8) molding: molding the powder obtained by spray granulation by using a die pressing process;

(9) plastic discharging: heating the formed material to 600-800 ℃, and keeping for 10-30 min;

(10) and (3) sintering: and conveying the molding material subjected to the plastic removal treatment to a sintering furnace for sintering, wherein the sintering temperature is 1320-1350 ℃, and the sintering time is 2-2.5 h.

2. The method of claim 1, wherein the rare earth in the formulation comprises niobium oxide, bismuth oxide, manganese carbonate, and sodium carbonate.

3. The method for preparing a lead-free piezoelectric ceramic material according to claim 1, wherein the weight of the binder added in the centrifugal granulation is 6.5% of the weight of the raw materials.

4. The method for preparing a lead-free piezoelectric ceramic material according to claim 1, wherein an inlet temperature of a spray tower in the centrifugal granulation is controlled to be 250 to 300 ℃, and an outlet temperature is controlled to be 100 to 120 ℃.

5. The method for preparing a lead-free piezoelectric ceramic material according to claim 3, wherein the adhesive is formulated as: 15% of polyvinyl alcohol, 7% of glycerol, 3% of alcohol and 75% of distilled water.

Technical Field

The invention relates to the technical field of piezoelectric ceramic materials, in particular to a preparation method of a lead-free piezoelectric ceramic material.

Background

Piezoelectric ceramic materials used in conventional transducers (ultrasonic vibrators) contain a large amount of lead. In the production process, the glaze is extremely harmful to the respiratory system of workers and damages the environment, the glaze is polluted by waste materials to cause heavy metal pollution, and lead powder volatilizes to pollute the air in the firing process. The piezoelectric ceramic material with low lead content produced in the prior art has low Curie temperature and low Kt value, and cannot be used for cleaning the transducer with high power.

Disclosure of Invention

The invention provides a preparation method of a lead-free piezoelectric ceramic material, which aims to solve the problems that the piezoelectric ceramic material contains lead metal and is polluted by heavy metal in the prior art.

In order to solve the technical problems, the invention provides a preparation method of a lead-free piezoelectric ceramic material, which comprises the following steps:

(1) preparing materials: the raw materials are selected according to the following weight percentage: barium carbonate BaCO 3: 67-68% of titanium dioxide TiO 2: 29-30% and rare earth: 3-3.1%;

(2) mixing materials: adding deionized water into a ball mill to grind various raw materials into primary slurry with the particle size of 1-3 um;

(3) drying: putting the primary slurry into a constant-temperature circulating oven, and evaporating water into a material block;

(4) crushing: crushing the dried material blocks, and sieving the crushed material blocks by a 20-mesh sieve;

(5) pre-burning: pre-burning the material blocks at 1250 ℃ for 3-5 h;

(6) secondary ball milling: adding deionized water into the pre-sintered material blocks by using a ball mill, grinding the material blocks into slurry with the particle size of 1-3 um, and putting the slurry into a sand mill to grind into secondary slurry with the particle size of 0.5-8 um;

(7) and (3) centrifugal granulation: adding an adhesive into the secondary slurry, stirring, feeding the stirred secondary slurry into a spray tower, controlling the temperature of the secondary slurry, and performing spray granulation;

(8) molding: molding the powder obtained by spray granulation by using a die pressing process;

(9) plastic discharging: heating the formed material to 600-800 ℃, and keeping for 10-30 min;

(10) and (3) sintering: and conveying the molding material subjected to the plastic removal treatment to a sintering furnace for sintering, wherein the sintering temperature is 1320-1350 ℃, and the sintering time is 2-2.5 h.

Preferably, the rare earth in the ingredients comprises niobium oxide, bismuth oxide, manganese carbonate and sodium carbonate.

Preferably, the weight of the binder added in the centrifugal granulation is 6.5% of the weight of the raw material.

Preferably, the inlet temperature of a spray tower in the centrifugal granulation is controlled to be 250-300 ℃, and the outlet temperature is controlled to be 100-120 ℃.

Preferably, the formulation of the adhesive is: 15% of polyvinyl alcohol, 7% of glycerol, 3% of alcohol and 75% of distilled water.

The invention has the following beneficial effects: compared with the prior art, the piezoelectric ceramic material prepared by the invention has good stability and mechanical strength, meets the material characteristic requirements of a high-power cleaning transducer, and has Kt more than 0.4 and high Curie temperature; meanwhile, the raw materials for preparation do not contain lead, so that heavy metal pollution is reduced, and the harm to the respiratory system of production workers is reduced.

Drawings

Fig. 1 is an SEM image of a crystal fracture state after chemical synthesis of a lead-free piezoelectric ceramic powder according to an embodiment of the present invention.

Fig. 2 is a characteristic data diagram of a component manufactured by a general piezoelectric ceramic material.

Fig. 3 is a characteristic data diagram of a component made of a lead-free piezoelectric ceramic material according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

The first embodiment is as follows:

a preparation method of a lead-free piezoelectric ceramic material comprises the following steps:

(1) preparing materials: the raw materials are selected according to the following weight percentage: barium carbonate BaCO 3: 67%, titanium dioxide TiO 2: 30% of rare earth: 3 percent;

(2) mixing materials: adding deionized water into a ball mill to grind various raw materials into primary slurry with the particle size of 1 um;

(3) drying: putting the primary slurry into a constant-temperature circulating oven, and evaporating water into a material block;

(4) crushing: crushing the dried material blocks, and sieving the crushed material blocks by a 20-mesh sieve;

(5) pre-burning: pre-sintering the material blocks, wherein the pre-sintering temperature is 1250 ℃, and the pre-sintering time is 5 hours;

(6) secondary ball milling: adding deionized water into the pre-sintered material blocks by using a ball mill, grinding into slurry with the particle size of 1um, and putting the slurry into a sand mill to grind into secondary slurry with the particle size of 0.5 um;

(7) and (3) centrifugal granulation: adding an adhesive into the secondary slurry, stirring, feeding the stirred secondary slurry into a spray tower, controlling the temperature of the secondary slurry, and performing spray granulation;

(8) molding: molding the powder obtained by spray granulation by using a die pressing process;

(9) plastic discharging: heating the formed material to 600 ℃, and keeping for 10 min;

(10) and (3) sintering: and (3) conveying the molding material subjected to the plastic removal treatment to a sintering furnace for sintering, wherein the sintering temperature is 1320 ℃, and the sintering time is 2 h.

The rare earth in the ingredients comprises niobium oxide, bismuth oxide, manganese carbonate and sodium carbonate.

The weight of the binder added in the centrifugal granulation is 6.5% of the weight of the raw materials.

The inlet temperature of a spray tower in the centrifugal granulation is controlled at 250 ℃, and the outlet temperature is controlled at 100 ℃.

The formula of the adhesive is as follows: 15% of polyvinyl alcohol, 7% of glycerol, 3% of alcohol and 75% of distilled water.

Example two:

a preparation method of a lead-free piezoelectric ceramic material comprises the following steps:

(1) preparing materials: the raw materials are selected according to the following weight percentage: barium carbonate BaCO 3: 67.9%, titanium dioxide TiO 2: 29% and rare earth: 3.1 percent;

(2) mixing materials: adding deionized water into a ball mill to grind various raw materials into primary slurry with the particle size of 3 um;

(3) drying: putting the primary slurry into a constant-temperature circulating oven, and evaporating water into a material block;

(4) crushing: crushing the dried material blocks, and sieving the crushed material blocks by a 20-mesh sieve;

(5) pre-burning: pre-sintering the material blocks, wherein the pre-sintering temperature is 1250 ℃, and the pre-sintering time is 5 hours;

(6) secondary ball milling: adding deionized water into the pre-sintered material blocks by using a ball mill, grinding into slurry with the particle size of 3um, and putting the slurry into a sand mill to grind into secondary slurry with the particle size of 8 um;

(7) and (3) centrifugal granulation: adding an adhesive into the secondary slurry, stirring, feeding the stirred secondary slurry into a spray tower, controlling the temperature of the secondary slurry, and performing spray granulation;

(8) molding: molding the powder obtained by spray granulation by using a die pressing process;

(9) plastic discharging: heating the formed material to 800 ℃, and keeping for 30 min;

(10) and (3) sintering: and (3) conveying the molding material subjected to the plastic removal treatment to a sintering furnace for sintering, wherein the sintering temperature is 1350 ℃, and the sintering time is 2.5 h.

The rare earth in the ingredients comprises niobium oxide, bismuth oxide, manganese carbonate and sodium carbonate.

The weight of the binder added in the centrifugal granulation is 6.5% of the weight of the raw materials.

The inlet temperature of a spray tower in the centrifugal granulation is controlled at 300 ℃, and the outlet temperature is controlled at 120 ℃.

The formula of the adhesive is as follows: 15% of polyvinyl alcohol, 7% of glycerol, 3% of alcohol and 75% of distilled water.

And finally, producing components according to the size requirement of the product to be produced by adopting the lead-free piezoelectric ceramic material.

The experimental method comprises the following steps: and respectively setting a comparison group and an experimental group, wherein the comparison group adopts components made of piezoelectric ceramic materials produced by the traditional process, the experimental group adopts components made of the lead-free piezoelectric ceramic materials produced by the method of the second embodiment of the invention, each group is provided with 10 groups, and the Kt value, Curie temperature and the like of each group of components are tested and collected.

The experimental results are as follows: as can be seen from the comparison between the control group and the experimental group, the Kt value of each group of the experimental group is greater than 0.4, the Kt value of the control group is less than 0.4, the Curie temperature of the experimental group is improved by 40% compared with that of the control group, and the performance of the piezoceramic material is improved.

In conclusion, the piezoelectric ceramic material prepared by the invention has good stability and mechanical strength, meets the material characteristic requirements of a high-power cleaning transducer, and has Kt more than 0.4 and high Curie temperature; meanwhile, the raw materials for preparation do not contain lead, so that heavy metal pollution is reduced, and the harm to the respiratory system of production workers is reduced.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.