CN107434410B

CN107434410B - Preparation method of cordierite ceramic powder

Info

Publication number: CN107434410B
Application number: CN201710748927.7A
Authority: CN
Inventors: 张丛; 曹剑武; 郭建斌; 燕东明; 高晓菊; 李志鹏; 乔光利; 王成; 满蓬; 邢文芳; 林广庆; 王志伟; 赵斌; 周雅伟; 方志坚; 刘发付; 梁西瑶; 常永威; 贾书波; 李康
Original assignee: No 52 Institute of China North Industries Group Corp Yantai Branch
Current assignee: No 52 Institute of China North Industries Group Corp Yantai Branch
Priority date: 2017-08-28
Filing date: 2017-08-28
Publication date: 2020-08-11
Anticipated expiration: 2037-08-28
Also published as: CN107434410A

Abstract

The invention relates to a method for preparing cordierite ceramic powder, which takes magnesia, alumina and silica powder as raw materials and adopts cordierite (2 MgO.2Al)₂O₃·5SiO₂Or Mg₂Al₄Si₅O₁₈) The chemical components are mixed and reacted to synthesize the high-purity cordierite low-thermal expansion ceramic powder. The preparation process comprises the following steps: firstly, ball milling and mixing high-purity powder; secondly, drying the slurry; thirdly, manually granulating and sieving; fourthly, high-purity cordierite powder is synthesized through high-temperature reaction. The purity of the cordierite powder material obtained by the invention is more than 98%, and the grain diameter of the cordierite powder without refinement treatment is about 20 μm. The cordierite synthesis method adopted by the invention is simple and convenient to operate, can avoid introducing impurities, obtains high-purity powder, is beneficial to the preparation of low-thermal-expansion ceramics in the later period, and is suitable for batch production.

Description

Preparation method of cordierite ceramic powder

Technical Field

The invention relates to a preparation method of cordierite ceramic powder, belonging to the technical field of ceramic preparation.

Background

Cordierite ceramic is always the preferred material for automobile exhaust purifiers due to excellent thermal shock resistance, higher mechanical strength and chemical corrosion resistance, and has wide application prospect in the field of electronic packaging and the aspect of precise semiconductor component materials. The high-purity and superfine cordierite powder is the key for obtaining the low-thermal expansion ceramic material, and the method for synthesizing the cordierite powder mainly comprises three methods: solid phase reaction, sol-gel, and glass crystallization. In contrast, the solid phase reaction method is the simplest to operate and has the lowest cost; although the sol-gel method can properly reduce the synthesis temperature, the synthesis purity is difficult to control; the glass crystallization method can obtain high-purity cordierite powder under low temperature conditions, but the operation process is complicated, the cost is high, and the industrialization is not facilitated. The solid phase reaction method comprises a natural mineral high-temperature solid phase synthesis method and a high-purity oxide synthesis method, wherein the cordierite powder is synthesized by natural mineral raw materials through solid phase reaction, and the raw materials often contain impurity elements, so that the purity of the synthesized powder is seriously influenced. The high-purity oxide synthesis method has been widely studied because it can synthesize high-purity cordierite powder at a relatively low temperature.

Disclosure of Invention

The invention provides a preparation method of cordierite ceramic powder, aiming at the problems that an impurity phase is easy to appear, the particle size of the powder is too large, the dispersibility of the powder is poor and the like in the existing preparation process of cordierite powder.

The technical scheme for solving the technical problems is as follows:

a method for preparing cordierite ceramic powder comprises the following steps:

1) mixing materials: mixing magnesium oxide, aluminum oxide and silicon oxide powder, wherein the magnesium oxide accounts for 13-14%, the aluminum oxide accounts for 34-35% and the silicon oxide accounts for 51-52% in parts by weight, then placing the mixture into a mixing tank, taking ethanol as a grinding medium, and grinding the mixture in a ball mill under the action of grinding medium balls;

2) and (3) drying: drying the slurry obtained after ball milling;

3) manual granulation and sieving: taking out the dried powder, carrying out cold isostatic pressing forming after vacuum sealing, crushing and sieving to obtain granulation powder with good fluidity;

4) reaction synthesis: placing the granulation powder obtained in the step 3) in an air atmosphere at 1350-1400 ℃ for reaction synthesis;

5) thinning treatment: and then ball-milling the powder obtained in the step 4) to meet the requirement of the required granularity.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the grinding time in the step 1) is 2-6 h.

Further, the grinding medium ball in the step 1) is a zirconia ball.

Further, the drying temperature in the step 2) is 80-100 ℃.

Further, the pressure of the cold isostatic pressing in the step 3) is 60-80 MPa, and the pressure is maintained for 5 s.

Further, the reaction time in the step 4) was 2 hours.

The preparation method has the following beneficial effects:

1) according to the method, the formula offset is increased according to the theoretical chemical formula design, the chemical composition deviates from the theoretical stoichiometric amount, the obtained powder has low crystallization degree, and the powder activity is increased, so that the powder synthesized by the method has the characteristics of high purity and high activity, the high quality stability in batch production can be ensured, and meanwhile, the preparation process of the cordierite low-thermal expansion ceramic has low sintering temperature, and high performance is obtained;

2) the method of the invention has simple operation, can synthesize high-purity cordierite powder at lower temperature, and can obtain low-thermal expansion ceramic powder with high purity, small grain diameter and good dispersibility.

Drawings

FIG. 1 is an XRD spectrum of cordierite powder obtained in examples 1 and 2;

FIG. 2 is an XRD spectrum of a cordierite powder obtained in example 3;

Detailed Description

The principles and features of this invention are described below in conjunction with examples, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

Example 1:

(1) mixing materials: high-purity MgO and Al with particle sizes of 1 μm, 0.5 μm and 30nm₂O₃、SiO₂Respectively mixing 13.8%, 34.8% and 51.4% by mass, placing in an alumina mixing tank, grinding with ethanol as grinding medium in a planetary ball mill for 4h at high speed under the action of zirconia balls;

(2) and (3) drying: after the mixing is finished, the slurry is placed in a drying oven at 80 ℃ for full drying;

(3) manual granulation and sieving: taking out the dried powder, carrying out cold isostatic pressing under the pressure of 80MPa after vacuum sealing, and then crushing and sieving by a 60-mesh sieve to obtain granulation powder with good fluidity;

(4) reaction synthesis: the granulated powder is placed in an alumina crucible and synthesized by reacting for 2 hours at the high temperature of 1400 ℃ in an oxidizing atmosphere furnace.

(5) Powder thinning treatment: and placing the sintered powder in a ball milling tank for high-speed ball milling to meet the requirement of the required granularity.

The effect of this embodiment: this embodiment can obtain high purity cordierite powder.

Example 2:

(1) mixing materials: high-purity MgO and Al with particle sizes of 1 μm, 0.5 μm and 30nm₂O₃、SiO₂Respectively mixing 13%, 35% and 52% by mass, placing in an alumina mixing tank, taking ethanol as a grinding medium, and grinding for 4h at high speed in a planetary ball mill under the action of zirconia balls;

(4) reaction synthesis: placing the granulated powder in an alumina crucible, and reacting at 1380 ℃ for 2h in an oxidizing atmosphere furnace to synthesize the granulated powder;

Example 3:

(1) mixing materials: high-purity MgO and Al with particle sizes of 75 μm, 0.5 μm and 75 μm respectively₂O₃、SiO₂Mixing 14%, 34% and 52% by mass respectively, placing in an alumina mixing tank, taking ethanol as a grinding medium, and grinding for 4h at high speed in a planetary ball mill under the action of zirconia balls;

(2) and (3) drying: after the mixing is finished, the slurry is placed in a drying oven at 100 ℃ for full drying;

(3) manual granulation and sieving: taking out the dried powder, carrying out cold isostatic pressing under the pressure of 60MPa after vacuum sealing, and then crushing and sieving by a 60-mesh sieve to obtain granulation powder with good fluidity;

(4) reaction synthesis: the granulated powder is placed in an alumina crucible and synthesized by reacting for 2 hours at the high temperature of 1350 ℃ in an oxidizing atmosphere furnace.

The effect of this embodiment: this embodiment can obtain a powder having a cordierite phase as a main crystal phase, accompanied by small amounts of magnesium aluminate spinel and silica phases.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A method for preparing cordierite ceramic powder is characterized by comprising the following steps:

(1) mixing materials: high-purity MgO and Al with particle sizes of 1 μm, 0.5 μm and 30nm₂O₃、SiO₂Respectively mixing 13%, 35% and 52% by mass, and placing in an alumina mixing tankTaking ethanol as a grinding medium, and grinding for 4 hours in a planetary ball mill at a high speed under the action of zirconia balls;