Search

CN-122010576-A - Preparation method of flaky ceramic

CN122010576ACN 122010576 ACN122010576 ACN 122010576ACN-122010576-A

Abstract

The invention discloses a preparation method of a flaky ceramic based on emulsion binder and water-permeable mold for rapid water absorption. The method prepares ceramic powder, water, dispersing agent and polymer emulsion into slurry, and pours the slurry into a porous mould with high water permeability. The capillary force of the mould or vacuum suction is used for assisting, the moisture in the slurry is quickly and directionally sucked out, and meanwhile, the emulsion particles are dehydrated, fused and formed into a film, so that the ceramic particles are in-situ solidified into a high-strength green body. The invention has the advantages of extremely high molding speed, uniform and compact blank, high green strength, small drying shrinkage and few defects, takes water as a medium and is environment-friendly. Is particularly suitable for high-efficiency low-cost preparation of large-size and thin flaky ceramics.

Inventors

  • LI SHIPENG
  • SUN HONGGANG
  • SUN XIAOFEI
  • ZHANG YIFAN
  • LIANG PENGPENG

Assignees

  • 中钢集团洛阳耐火材料研究院有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (7)

  1. 1. A preparation method of flaky ceramic is characterized by comprising the following steps: S1, ball-milling and mixing ceramic powder, deionized water and a dispersing agent to prepare uniform and stable ceramic suspension, adding polymer emulsion serving as a binder into the ceramic suspension, adding a defoaming agent, and stirring and mixing at a low speed to obtain ceramic slurry with the viscosity in the range of 500-3000 mPa & S; S2, carrying out vacuum degassing treatment on the ceramic slurry prepared in the step S1 to eliminate bubbles introduced in the stirring process, and then pouring the degassed ceramic slurry into a cavity of a permeable mold, wherein the permeable mold can be arranged at the bottom and the periphery or only at the bottom of a sheet ceramic product; s3, after casting, utilizing the water permeability of the water permeable mould, and enabling moisture in the slurry to be sucked out rapidly through vacuum suction or natural capillary force action on the back surface of the mould, wherein polymer emulsion particles in the slurry are gradually close to and stacked along with migration of the moisture and form bridging among ceramic particles; S4, demolding the flaky biscuit, drying and sintering at high temperature to obtain the final flaky ceramic biscuit, and discharging glue and sintering the biscuit to obtain a compact flaky ceramic finished product.
  2. 2. The method for preparing a ceramic flake according to claim 1, wherein the ceramic flake comprises the following components in step S1: 10-40 wt% of deionized water; 0.3-2.0 wt% of dispersing agent; 3-10 wt% of polymer emulsion (solid content); 0.1 to 0.5 wt percent of defoaming agent.
  3. 3. The method of claim 1, wherein the polymer emulsion in the step S1 is an aqueous emulsion selected from at least one of an acrylic emulsion, a styrene-acrylic emulsion, a vinyl acetate-ethylene copolymer emulsion, and a styrene-butadiene emulsion.
  4. 4. A method of producing a sheet ceramic according to claim 3, wherein the polymer emulsion has an average particle diameter of 50 to 300 nm and a glass transition temperature of-10 ℃ to 25 ℃.
  5. 5. The method according to claim 3, wherein the water permeable mold in step S2 is a porous mold having micro-scale through pores, and is made of one of porous gypsum, porous ceramic, porous resin, and a rigid mold having a porous filter membrane coated on the surface.
  6. 6. The method according to claim 1, wherein in step S3, the water absorption process is accelerated by applying a vacuum negative pressure of-0.05 to-0.1 MPa to the back surface of the water permeable mold.
  7. 7. The method for producing a sheet ceramic according to claim 1, wherein the ceramic powder is at least one selected from the group consisting of alumina, zirconia, silicon carbide and silicon nitride, and the powder D50 is 0.1 to 5.0 μm.

Description

Preparation method of flaky ceramic Technical Field The invention belongs to the technical field of ceramic preparation, and particularly relates to a preparation method of flaky ceramic. Background The sheet ceramic (such as ceramic substrate, membrane electrode support, etc.) has wide application in the fields of electronics, energy, chemical industry, etc., and the traditional preparation method of the sheet ceramic mainly comprises dry press molding, tape casting, slip casting, etc. The dry press molding is suitable for products with simple shapes, but has the problems of uneven density, spalling, edge effect and the like for large-size lamellar products, the tape casting can prepare high-quality sheets, but has the defects of complex process, high cost, environmental pollution, long drying period, easiness in warping of a blank body and the like due to the fact that a large amount of organic solvents and plasticizers are needed, the slip casting uses a gypsum mold, water is absorbed by virtue of capillary force, the molding speed is low, the dehydration efficiency for fine particle slurry is low, and the blank body strength is usually not high. In recent years, some improvement methods such as pressure-assisted filtration, gel casting, and the like have been proposed. However, the methods either require complex equipment or the introduced reaction monomer may affect the health and environment of operators, and the problems of large drying shrinkage, many defects of green bodies and the like still exist, so that the development of a preparation method of the flaky ceramic with simple process, high forming speed, good green body uniformity, high strength and environmental friendliness has important industrial application value. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a preparation method of a flaky ceramic based on emulsion binder and rapid water absorption of a water permeable mold; according to the method, emulsion is used as a binder, and a porous mold with high air permeability and water permeability is combined, so that the quick dehydration of slurry and the in-situ solidification of a blank body are realized, the forming period is obviously shortened, and the flaky ceramic biscuit with uniform structure, high strength and few defects is obtained. The technical scheme adopted by the invention for not finishing the purposes is as follows: A preparation method of flaky ceramic comprises the following specific steps: Step 1, slurry preparation Adding polymer emulsion as binder into the ceramic suspension, adding defoamer, stirring and mixing at low speed to obtain ceramic slurry with viscosity in the range of 500-3000 mPa s; The ceramic powder comprises, but is not limited to, aluminum oxide, zirconium oxide, silicon nitride and silicon carbide, wherein the powder D50 is 0.1-5.0 mu m, and the weight of the ceramic powder is taken as a reference, and the contents of the components are as follows: 10-40 wt% of deionized water; 0.3-2.0 wt% of dispersing agent; 3-10 wt% of polymer emulsion (solid content); 0.1 to 0.5 wt percent of defoaming agent. The polymer emulsion is water-based polymer emulsion, preferably one or more of acrylic ester emulsion, styrene-acrylic emulsion, vinyl acetate-ethylene copolymer emulsion (VAE) and styrene-butadiene emulsion, wherein the average particle size of the emulsion is 50-300 nm, and the glass transition temperature (Tg) is-10 ℃ to 25 ℃; Step 2, removing bubbles in vacuum and pouring The ceramic slurry prepared in the step 1 is subjected to vacuum degassing treatment to eliminate bubbles introduced in the stirring process, and then the degassed ceramic slurry is poured into a cavity of a permeable mold, wherein the permeable mold can be arranged at the bottom and the periphery or only at the bottom of a sheet-shaped ceramic product; further, the water permeable mould is a porous mould with micron-sized through holes, and is made of one of porous gypsum, porous ceramic, porous resin or a rigid mould with a porous filter membrane coated on the surface; Step 3, solidifying and forming After casting, the porous characteristic of the permeable mould is utilized, and the moisture in the slurry is quickly sucked out through the vacuum suction or natural capillary force action on the back of the mould, so that the viscosity of the slurry is quickly increased, and the ceramic powder is not easy to subside. At the same time, the polymer emulsion particles in the slurry gradually approach and accumulate along with the migration of moisture, and form bridging between ceramic particles. With the further absorption of water, the emulsion particles are fused and formed into a film, so that the ceramic particles are firmly bonded together, and the slurry is quickly converted into a solid biscuit. The water absorption curing process can be completed within 1-30 minutes, and the specific time depends on the thickness of slurry, th