METHOD FOR PREPARING PEROVSKITE NANOPOWDER THROUGH A RHEOLOGICAL PHASE REACTION AT LOW-TEMPERATURE

Abstract

A method for preparing perovskite nanopowder through a rheological phase reaction at low-temperature that can include: taking hydroxide and metallorganic compound as initial reactants; mixing and stirring the reaction raw materials to form a solid-liquid rheological phase mixture; and controlling the reaction temperature and period, under a low-temperature condition, to prepare perovskite nanopowder in nearly spherical shape and a size of 20-100 nm. This allows for advantages such as controllable product size, low cost, high yield per unit volume, environmental friendliness, high yield per unit volume, and high repeatability. The perovskite nanopowder obtained by this way is nearly spherical, are uniform in size distribution and have controllable granularity. This can be used as the ceramic substrate for electronic components such as high-end chip capacitors and PTC thermistors, etc., as well as the raw material for manufacturing ceramic 3D printing additives and electronic ceramic ink.

Claims

1. A method for preparing perovskite nanopowder through a rheological phase reaction at low-temperature, wherein the hydroxide and metallorganic compound(s), as starting reactants, are mixed and stirred to form a solid-liquid rheological mixture; by controlling the reaction temperature and period, multinary oxide perovskite nano powder in uniform size is obtained under a low-temperature condition, comprising the following specific operation steps of: a. placing first barium hydroxide, barium hydroxide monohydrate, barium hydroxide octahydrate, calcium hydroxide or lead hydroxide octahydrate and then metallorganic compound tetrabutyl titanate, tetrabutyl zirconate, titanium isopropoxide or zirconium isopropoxide, in a molar ratio of 1:1, into a beaker, stirring for 30 min, and mixing well to form a uniform rheological phase mixture; or placing first barium hydroxide monohydrate, barium hydroxide octahydrate, calcium hydroxide or lead hydroxide octahydrate and then metallorganic compounds tetrabutyl titanate and tetrabutyl zirconate, or titanium isopropoxide and tetrabutyl zirconate, in a molar ratio of 1:0.2-0.8:0.2-0.8, into a beaker, stirring for 30 min, and mixing well to form a uniform rheological phase mixture; b. transferring the rheological phase mixture obtained in step a into a sealed reactor, wherein the mixture occupies 10-80% of the sealed reactor's volume; c. placing the sealed reactor of step b in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature is 80-160° C., and the reaction period is 0.5-15 h; d. washing the product obtained in step c with 0.05-0.2 mol/L dilute hydrochloric acid for 3 times, and dispersing the washed product into a centrifuge tube with deionized water or absolute ethanol as the dispersion medium, wherein the centrifuge is rotated at a speed of 3000-5000 r/min, for 10-30 min each time and 3-5 times repeatedly; then placing the centrifuge tube in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical binary or multinary metal oxide perovskite phase nanopowder in a size of 20-100 nm.

Description

DESCRIPTION OF DRAWINGS

[0020] FIG. 1 is the XRD pattern of the barium titanate (BaTiO.sub.3) nanopowder prepared by the present invention, showing that it is a single perovskite phase;

[0021] FIG. 2 is the scanning electron microscope picture of the barium titanate(BaTiO.sub.3) nanopowder prepared by the present invention.

SPECIFIC MODES FOR CARRYING OUT THE INVENTION

EXAMPLE 1

[0022] a. First lead hydroxide octahydrate and then metallorganic compound zirconium isopropoxide were placed into a beaker at a molar ratio of 1:1, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0023] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 10% of the sealed reactor's volume;

[0024] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 80° C., and the reaction period was 15 h;

[0025] d. The product obtained in step c was washed 3 times with 0.05mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with absolute ethanol as the dispersion medium, wherein the centrifuge was rotated at a speed of 3000 r/min, for 20 min each time and 5 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase lead zirconate (PbZrO.sub.3) nanopowder in a size of 50 nm.

EXAMPLE 2

[0026] a. First barium hydroxide octahydrate and then metallorganic compound tetrabutyl titanate were placed into a beaker at a molar ratio of 1:1, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0027] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 50% of the sealed reactor's volume;

[0028] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 120° C., and the reaction period was 2 h;

[0029] d. The product obtained in step c was washed 3 times with 0.1 mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with deionized water as the dispersion medium, wherein the centrifuge was rotated at a speed of 4000 r/min, for 30 min each time and 5 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase barium titanate (BaTiO.sub.3) nanopowder (FIG. 1) in a size of 30 nm (FIG. 2).

EXAMPLE 3

[0030] a. First barium hydroxide monohydrate and then metallorganic compound titanium isopropoxide were placed into a beaker at a molar ratio of 1:1, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0031] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 80% of the sealed reactor's volume;

[0032] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 160° C., and the reaction period was 6 h;

[0033] d. The product obtained in step c was washed 3 times with 0.2 mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with deionized water as the dispersion medium, wherein the centrifuge was rotated at a speed of 5000 r/min, for 30 min each time and 5 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase barium titanate (BaTiO.sub.3) nanopowder in a size of 100 nm.

EXAMPLE 4

[0034] a. First barium hydroxide and then metallorganic compound tetrabutyl zirconate were placed into a beaker at a molar ratio of 1:1, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0035] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 30% of the sealed reactor's volume;

[0036] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 100° C., and the reaction period was 8 h;

[0037] d. The product obtained in step c was washed 3 times with 0.15 mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with absolute ethanol as the dispersion medium, wherein the centrifuge was rotated at a speed of 3500 r/min, for 15 min each time and 4 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase barium zirconate (BaZrO.sub.3) nanopowder in a size of 50 nm.

EXAMPLE 5

[0038] a. First calcium hydroxide and then metallorganic compounds tetrabutyl titanate and tetrabutyl zirconate were placed into a beaker at a molar ratio of 1:0.5:0.5, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0039] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 60% of the sealed reactor's volume;

[0040] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 120° C., and the reaction period was 0.5 h;

[0041] d. The product obtained in step c was washed 3 times with 0.12 mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with deionized water as the dispersion medium, wherein the centrifuge was rotated at a speed of 4500 r/min, for 25 min each time and 5 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase calcium zirconate-titanate (CaZr.sub.0.5Ti.sub.0.5O.sub.3) nanopowder in a size of 80 nm.

EXAMPLE 6

[0042] a. First calcium hydroxide and then metallorganic compounds tetrabutyl titanate and tetrabutyl zirconate were placed into a beaker at a molar ratio of 1:0.8:0.2, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0043] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 50% of the sealed reactor's volume;

[0044] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 110° C., and the reaction period was 1.5 h;

[0045] d. The product obtained in step c was washed 3 times with 0.12 mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with deionized water as the dispersion medium, wherein the centrifuge was rotated at a speed of 4500 r/min, for 25 min each time and 5 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase calcium zirconate-titanate (CaZr.sub.0.2Ti.sub.0.5O.sub.3) nanopowder in a size of 70 nm.

EXAMPLE 7

[0046] a. First barium hydroxide monohydrate and then metallorganic compounds titanium isopropoxide and tetrabutyl zirconate were placed into a beaker at a molar ratio of 1:0.5:0.5, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0047] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 70% of the sealed reactor's volume;

[0048] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 150° C., and the reaction period was 6 h;

[0049] d. The product obtained in step c was washed 3 times with 0.12 mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with deionized water as the dispersion medium, wherein the centrifuge was rotated at a speed of 4500 r/min, for 25 min each time and 5 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase barium zirconate-titanate (BaZr.sub.0.5Ti.sub.0.5O.sub.3) nanopowder in a size of 90 nm.

EXAMPLE 8

[0050] a. First lead hydroxide octahydrate and then metallorganic compounds tetrabutyl titanate and tetrabutyl zirconate were placed into a beaker at a molar ratio of 1:0.5:0.5, stirred for 30 min, and mixed well to form a uniform rheological phase mixture;

[0051] b. The rheological phase mixture obtained in step a was transferred to a sealed reactor, wherein the mixture occupied 60% of the sealed reactor's volume;

[0052] c. The sealed reactor of step b was placed in an incubator to allow the mixture to react at a low temperature, wherein the reaction temperature was 130° C., and the reaction period was 10 h;

[0053] d. The product obtained in step c was washed 3 times with 0.12 mol/L dilute hydrochloric acid, dispersed into a centrifuge tube with deionized water as the dispersion medium, wherein the centrifuge was rotated at a speed of 4500 r/min, for 25 min each time and 5 times repeatedly; the centrifuge tube was placed in a vacuum oven to dry for 24 h to obtain monodisperse near-spherical perovskite-phase lead zirconate-titanate (PbZr.sub.0.5Ti.sub.0.5O.sub.3) nanopowder in a size of 60 nm.