CN101358388A - A kind of PZT piezoelectric fiber and preparation method thereof - Google Patents

Abstract

The invention relates to a piezoelectric fiber and a manufacturing method thereof. The PZT piezoelectric fiber is prepared by a sol-powder blending extrusion method, specifically mixing the sol and PZT powder uniformly in proportion, and then extruding the mixture into a fiber with a certain diameter in an extruder, drying and sintering; Wherein said sol contains lead acetate, zirconium nitrate, tetrabutyl titanate, water, acetic acid. The invention improves the density of the cellulose blank, reduces the shrinkage rate of the fiber, and improves the shrinkage deformation of the fiber. The method of the invention also improves the defect of bending deformation of the fiber extruded by the traditional extrusion method, and can precisely control the diameter, length and shrinkage rate of the fiber at the same time. The PZT piezoelectric fiber of the present invention has a single perovskite phase structure, high density, smooth fiber, 80-1000 μm in diameter, high piezoelectric performance, and can be used for 1-3 piezoelectric fiber composites in sensing/driving devices The material is PZT piezoelectric fiber.

Description

A kind of PZT piezoelectric fiber and preparation method thereof

technical field

The invention relates to the field of functional ceramic fibers, in particular to a novel lead zirconate titanate (PZT) piezoelectric fiber and a manufacturing method thereof.

Background technique

Piezoelectric fibers have great potential applications in the fields of sensors, drives, ultrasonic sensor devices, automobiles, and aviation due to their high piezoelectric strain constant, thickness electromechanical coupling coefficient, low mechanical quality factor, and acoustic impedance. . At present, the preparation methods of piezoelectric fibers mainly include: sol-gel method, suspended magnetic powder spinning method and plastic polymer method. US Patent U.S.Pat.No.4921328 and German R.Harsch etc. have prepared PZT fibers by sol-gel method, with a diameter of 50-150 μm. The disadvantage is that the internal structure of piezoelectric fibers prepared by this method is low due to the low solid content. An obvious core-shell structure is formed, the outer layer is very dense, and there are many voids inside, resulting in a decrease in fiber uniformity, and the shape of the fiber is not well controlled, resulting in a significant decrease in the piezoelectric effect. Advanced Cerametrics of the United States prepared PZT fibers with a cross-sectional size of 80-300 μm by suspending magnetic powder spinning. However, since this method uses a large amount of organic polymers as carriers, the volatilization of polymers will cause microporous. In addition, the high viscosity of the suspension makes it difficult to control fibers with small diameters. Zhou Jing et al. used the plastic polymer method to prepare PZT ceramic fibers with a diameter of 300 μm. The disadvantage of this method is that a certain amount of polyvinyl alcohol (PVA) is added to the polymer, and some micropores and ash are left inside the fiber during debinding. resulting in a decrease in fiber density.

Contents of the invention

The present invention provides a PZT piezoelectric fiber and a preparation method thereof in order to solve the deficiencies in the above-mentioned prior art.

The technical solution of the present invention to solve the technical problem is: a PZT piezoelectric fiber is prepared by the sol-powder blending extrusion method, specifically, the sol and the PZT powder are uniformly mixed according to the mass ratio of 1:1 to 1:9. Mix, then extrude the mixture into fibers with a certain diameter on the extruder at 60°C, dry and sinter to obtain PZT piezoelectric fibers; the said sol contains lead acetate, zirconium nitrate, tetrabutyl titanate, water, acetic acid , the concentration of the sol is 0.3mol/l, the mass ratio of lead acetate, zirconium nitrate and tetrabutyl titanate is 110:56:44, and the volume ratio of water and acetic acid is 1:0.5-1:3.

The preparation method of the PZT piezoelectric fiber of the present invention is characterized in that the sol and the PZT powder are uniformly mixed in a mass ratio of 1:1 to 1:9, and then the mixture is extruded on an extruder at 60° C. diameter fibers, dried and sintered to obtain PZT piezoelectric fibers; wherein said sol contains lead acetate, zirconium nitrate, tetrabutyl titanate, water, acetic acid, the concentration of the sol is 0.3mol/l, lead acetate, zirconium nitrate, The mass ratio of tetrabutyl titanate is 110:56:44, and the volume ratio of water and acetic acid is 1:0.5˜1:3.

The preparation method of PZT piezoelectric fiber of the present invention is specifically carried out according to the following steps:

(1) Preparation of PZT sol: lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44 were ultrasonically dissolved in an organic solvent, and an appropriate amount of stabilizer was added, and the precursor solutions of the three Mix, under the conditions of low temperature heating at 80°C and ultrasonic oscillation, add water and acetic acid with a volume ratio of 1:0.5 to 1:3 to adjust the degree of hydrolysis of the solution, adjust the concentration of the sol to 0.3mol/l, and stir under magnetic force Mix the mixture evenly to obtain the sol;

(2) Preparation of sol-powder mixing system: mix sol and PZT powder at a mass ratio of 1:1 to 1:9, heat at 80°C with low temperature and uniform stirring, and grind for several minutes with a mortar, or grind with a rolling mill. The film machine is rolled to make the mixture fully mixed evenly and have suitable plasticity;

(3) Preparation of PZT piezoelectric fiber: the plastic mixture obtained in the above (2) is placed in a suitable preheated mold, and under a certain pressure and low temperature heating at 60°C, the cellulose billet is prepared on an extruder, and the fiber The green body is placed on flat glass to dry at room temperature to remove the adsorbed water on the surface of the fiber;

(4) Heat treatment of PZT piezoelectric fibers: the fibers dried at room temperature were dried in a low-temperature drying oven, and then heat-treated to obtain PZT piezoelectric fibers.

In the manufacturing method of the PZT piezoelectric fiber of the present invention, the solvent and the stabilizer in the sol are commonly used organic substances, such as ethylene glycol monomethyl ether, ethylene glycol ether, ethylene glycol, and stabilizers such as acetylacetone, poly Acrylic acid, sodium polyacrylate, etc.

In the manufacturing method of the novel PZT piezoelectric fiber of the present invention, in the sol powder system, the powders are common PZT powders, such as PZT5, wherein Zr:Ti=56:44.

In the manufacture method of PZT piezoelectric fiber of the present invention, described water and acetic acid ratio are 1: 0.5～1: 3, but when water and acetic acid ratio is 1: 0.65～1: 1.5, it is an ideal range, if the ratio is too large, then Because the water content is too high, the hydrolysis rate of the sol is faster, and the gel will be formed and lose its plasticity; on the contrary, if the proportion is too small, the content of acetic acid is too high, although it is beneficial to inhibit the progress of hydrolysis, but in the process of drying and firing , acetic acid will volatilize, expanding the shrinkage of the fiber, and leaving a large number of pores at the same time, reducing the density and strength of the fiber, so the ratio of water and acetic acid is required to be within the stated range.

In the manufacturing method of the PZT piezoelectric fiber of the present invention, the ratio of the sol to the PZT powder is 1:1 to 1:9, the solid phase content reaches 50% to 90%, and the ideal ratio is 1:4 to 1:8. When the proportion is too large, the solid phase content is low, the mixture is in a rheological state, the viscosity is too low, fibers cannot be formed, and even if the fibers are formed, they are easily deformed. On the contrary, the proportion is too low, the mixture loses plasticity, and continuous and uniform long fibers cannot be extruded. Therefore, the ratio of the sol and the PZT powder is required to be within the above range.

In step (3) of the manufacturing method of the PZT piezoelectric fiber of the present invention, the extrusion pressure is conventional, preferably 5-20 MPa. The mold is heated at a low temperature of 60°C in order to increase the extrusion rate of the fiber and maintain the plasticity of the mixture.

The step (4) of the manufacturing method of the PZT piezoelectric fiber of the present invention may specifically be: drying the fiber after drying at room temperature in a drying oven at 80 to 100°C, and then arranging it on a flat ceramic sheet, and spreading a lead-containing atmosphere material around it , covered with a crucible, for heat treatment.

The specific heat treatment process is: 1. From room temperature to 200°C, the heating rate is 1°C/min, and the temperature is kept at 200°C for 1 hour, mainly due to the volatilization of moisture and some organic matter in the fiber precursor; 2. 200-600°C, the heating rate is 2°C/min, Heat preservation at 600°C for 1-2 hours, mainly for volatilization and decomposition of organic matter and crystallization of PZT fibers; 3.600°C to sintering temperature, heating rate 200°C/h, mainly for grain growth, fiber densification and discharge of pores, heat preservation 2h.

Compared with the existing preparation method, the present invention has the outstanding advantages: PZT sol is used to replace the organic binder in the traditional sol-gel method, thus avoiding the deformation of the fiber and the organic bonding of the fiber during the drying and debinding process After the agent is removed, micropores are left, thereby increasing the density of the cellulose base, reducing the shrinkage rate of the fiber, and improving the shrinkage deformation of the fiber. Secondly, the present invention adopts the sol-powder blending extrusion process, which improves the defect that the extruded fiber is bent and deformed by adding a large amount of organic matter in the traditional extrusion method, and can precisely control the diameter, length and fiber shape of the fiber at the same time. Shrinkage. The PZT piezoelectric fiber of the present invention has a single perovskite phase structure, high density, smooth fiber, 80-1000 μm in diameter, high piezoelectric performance, and can be used for 1-3 piezoelectric fiber composites in sensing/driving devices The material is PZT piezoelectric fiber.

Description of drawings

Figure 1 is the X-ray diffraction spectrum of PZT piezoelectric fiber sintered at 1240°C. In Figure 1, the abscissa is the diffraction angle, and the ordinate is the diffraction intensity.

Fig. 2 is a scanning electron microscope image of a PZT piezoelectric fiber section sintered at 1240°C.

Detailed ways

The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those skilled in the art.

The present invention will be described in further detail below in conjunction with specific examples and with reference to data. It should be understood that these examples are only for illustration of the present invention, but not to limit the scope of the present invention in any way.

In the following examples, various procedures and methods not described in detail are conventional methods well known in the art. The sources and trade names of the reagents used, as well as those whose components must be listed, are indicated when they appear for the first time, and the same reagents used thereafter are the same as those indicated for the first time unless otherwise specified.

Example 1:

(1) Take 20 parts of lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44, dissolve and mix them uniformly with ethylene glycol monomethyl ether, add water, acetic acid and a small amount of acetylacetone at a volume ratio of 1:0.65 As a stabilizer, adjust the solution concentration to 0.3mol/l under magnetic stirring to obtain a sol,

(2) Weigh 80 parts of PZT powder according to the sol:PZT powder mass ratio of 1:4, heat at 80°C with low temperature and uniform stirring, and then use a mortar for grinding for several minutes, or roll it with a rolling machine, so that the mixture is fully Mix evenly and have suitable plasticity;

(3) Preparation of PZT piezoelectric fiber: the plastic mixture obtained in the above (2) is placed in a suitable preheated mold, and the cellulose billet is prepared on an extruder under a pressure of 5-20 MPa and a low temperature heating of 60 ° C. Place the cellulose blank on flat glass to dry at room temperature, and remove the adsorbed water on the surface of the fiber;

(4) Heat treatment after drying and firing at 1200°C to obtain PZT piezoelectric fibers.

It is determined that the density of the piezoelectric fiber is 6.1g/cm ³ , and the radial shrinkage rate is 17.4%.

Example 2:

Take 20 parts of lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44, dissolve and mix them evenly with ethylene glycol ether, add water, acetic acid and a small amount of polyacrylic acid at a volume ratio of 1:1 as stabilizers, and Under the action of magnetic stirring, adjust the concentration of the solution to 0.3 mol/l to obtain a sol, weigh 80 parts of PZT powder according to the mass ratio of sol:PZT powder of 1:5, and mix uniformly to prepare a plastic sol powder system. Fibers with a certain diameter were extruded on an extruder at 60°C, dried and fired at 1240°C to obtain dried fibers. The density of the piezoelectric fibers was measured to be 6.4g/cm ³ and the radial shrinkage rate was 17.1%.

Example 3:

Take 20 parts of lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44, dissolve and mix them evenly with ethylene glycol monomethyl ether, add water, acetic acid and a small amount of sodium polyacrylate at a volume ratio of 1:0.5 to stabilize Under the action of magnetic stirring, adjust the concentration of the solution to 0.3mol/l to obtain a sol, weigh 80 parts of PZT powder according to the mass ratio of sol:PZT powder of 1:1, and uniformly mix to prepare a plastic sol powder system. Extrude fibers with a certain diameter at 60°C on an extruder, and burn them at 1200°C after drying to obtain dry fibers. It is determined that the density of the piezoelectric fiber is 6.7g/cm ³ , and the shrinkage rate in the radial direction is 18%.

Example 4:

Take 20 parts of lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44, dissolve and mix them evenly with ethylene glycol, add water, acetic acid and a small amount of acetylacetone at a volume ratio of 1:1.5 as stabilizers, and Adjust the concentration of the solution to 0.3 mol/l under stirring to obtain a sol, weigh 80 parts of PZT powder according to the sol:PZT powder mass ratio of 1:6, and mix uniformly to prepare a plastic sol powder system. Extrude fibers with a certain diameter at 60°C on an extruder, and burn them at 1200°C after drying to obtain dry fibers. It is determined that the density of the piezoelectric fiber is 6.9g/cm ³ , and the shrinkage rate in the radial direction is 17.0%.

Example 5:

Take 20 parts of lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44, dissolve and mix them evenly with ethylene glycol monomethyl ether, add water, acetic acid and a small amount of sodium polyacrylate at a volume ratio of 1:3 for stabilization Under the action of magnetic stirring, adjust the concentration of the solution to 0.3 mol/l to obtain a sol, weigh 80 parts of PZT powder according to the mass ratio of sol:PZT powder of 1:9, and uniformly mix to prepare a plastic sol powder system. Extrude fibers with a certain diameter on the extruder at 60°C, dry them and burn them at 1240°C to obtain dry fibers. It is determined that the density of the piezoelectric fiber is 7.3g/cm ³ , and the radial shrinkage rate is 16.0%.

Embodiment 6:

Take 20 parts of lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44, dissolve and mix them evenly with ethylene glycol monomethyl ether, add water, acetic acid and a small amount of acetylacetone at a volume ratio of 1:1.5 as a stabilizer , adjust the concentration of the solution to 0.3mol/l under the action of magnetic stirring to obtain a sol, weigh 80 parts of PZT powder according to the mass ratio of sol:PZT powder of 1:8, and uniformly mix to prepare a plastic sol powder system. Fibers with a certain diameter are extruded at 60°C on an extruder, and fired at 1240°C after drying to obtain dry fibers. The X-ray diffraction spectrum is shown in Figure 1, showing that the fibers have a single perovskite phase; PZT pressed The scanning electron microscope picture of the electrical fiber section sintered at 1240°C (Fig. 2). The cross-sectional morphology of the fiber in the figure shows that the fiber is relatively dense and has no pores. It is determined that the density of the piezoelectric fiber is 7.3g/cm ³ , and the radial shrinkage rate is 15.8%.

Claims (5)

1. A PZT piezoelectric fiber is characterized in that it is prepared by a sol-powder blending extrusion method, specifically, the sol and the PZT powder are uniformly mixed in a mass ratio of 1:1 to 1:9, and then the mixture is Extrude fibers with a certain diameter on the extruder at 60°C, dry and sinter to obtain PZT piezoelectric fibers; the sol contains lead acetate, zirconium nitrate, tetrabutyl titanate, water, acetic acid, and the concentration of the sol is 0.3 mol/l, the mass ratio of lead acetate, zirconium nitrate and tetrabutyl titanate is 110:56:44, and the volume ratio of water and acetic acid is 1:0.5-1:3. 2. A method for preparing the PZT piezoelectric fiber according to claim 1, characterized in that the sol and the PZT powder are uniformly mixed at a mass ratio of 1:1 to 1:9, and then the mixture is placed on an extruder at 60° C. Extrude fibers with a certain diameter, dry and sinter to obtain PZT piezoelectric fibers; wherein said sol contains lead acetate, zirconium nitrate, tetrabutyl titanate, water, acetic acid, the concentration of the sol is 0.3mol/l, lead acetate The mass ratio of zirconium nitrate and tetrabutyl titanate is 110:56:44, and the volume ratio of water and acetic acid is 1:0.5-1:3. 3, according to the preparation method of the described PZT piezoelectric fiber of claim 2, it is characterized in that, concrete steps are as follows: (1) Preparation of PZT sol: lead acetate, zirconium nitrate, and tetrabutyl titanate with a mass ratio of 110:56:44 were ultrasonically dissolved in an organic solvent, and an appropriate amount of stabilizer was added, and the precursor solutions of the three Mix, under the conditions of low temperature heating at 80°C and ultrasonic oscillation, add water and acetic acid with a volume ratio of 1:0.5 to 1:3 to adjust the degree of hydrolysis of the solution, adjust the concentration of the sol to 0.3mol/l, and stir under magnetic force Mix the mixture evenly to obtain the sol; (2) Preparation of sol-powder mixing system: mix sol and PZT powder at a mass ratio of 1:1 to 1:9, heat at 80°C with low temperature and uniform stirring, and then grind for several minutes with a mortar, or grind with a rolling mill. The film machine is rolled to make the mixture fully mixed evenly and have suitable plasticity; (3) Preparation of PZT piezoelectric fiber: the plastic mixture obtained in the above (2) is placed in a suitable preheated mold, and under a certain pressure and low temperature heating at 60°C, the cellulose billet is prepared on an extruder, and the fiber The green body is placed on flat glass to dry at room temperature to remove the adsorbed water on the surface of the fiber; (4) Heat treatment of PZT piezoelectric fibers: the fibers dried at room temperature were dried in a low-temperature drying oven, and then heat-treated to obtain PZT piezoelectric fibers. 4. The method for preparing PZT piezoelectric fibers according to claim 2 or 3, characterized in that the ratio of said sol to PZT powder is 1:4˜1:8. 5. The preparation method of the PZT piezoelectric fiber according to claim 2 or 3, characterized in that the ratio of said water to acetic acid is 1:0.65˜1:1.5.

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