CN-117303877-B - Method for preparing high-performance structural ceramic based on binder spraying technology

Abstract

The invention discloses a method for preparing high-performance structural ceramics based on a binder spraying technology, and relates to the technical field of additive manufacturing. The invention firstly mixes ceramic powder and sintering aid uniformly, then adds mixed suspension containing metal salt, silica sol and glue, and makes granulation to prepare coarse powder, and uses binder injection technique to make blank, and makes the blank undergo the processes of degreasing and sintering so as to obtain the ceramic base core. The invention prepares micron-sized coarse powder by using ceramic powder with high sintering activity, sintering aid powder, metal salt compound, silica sol and glue, and then prepares a ceramic printing sample by using a binder spraying process, thereby obtaining a printing blank with higher strength, keeping the blank with higher strength after degreasing, being beneficial to preparing structural ceramic with high compactness and high strength by high-temperature sintering, and solving the problem that the binder spraying additive manufacturing technology is difficult to prepare high-density high-performance ceramic.

Inventors

• WU SHANGHUA
• LI JIANBIN

Assignees

• 广东工业大学

Dates

Publication Date

20260508

Application Date

20230925

Claims (8)

1. 1. A method for preparing high-performance structural ceramics based on binder spraying technology, which is characterized by comprising the following steps: S1, uniformly mixing 80-99 parts of ceramic powder and 1-20 parts of sintering aid according to parts by mass, adding mixed suspension containing 20-30 parts of metal salt, 20-30 parts of silica sol and 20-30 parts of glue into the mixed powder, and extruding, stirring and granulating to prepare coarse powder with the particle size of 0.1-150 mu m; S2, forming the coarse powder into blanks by using a binder injection technology, wherein the loose density of the coarse powder is 35% and the tap density is 42% or 45%; s3, degreasing and sintering the blank to obtain a ceramic matrix core; When the binder is sprayed and printed, the binder is sprayed with glue to enter a powder bed and then is mixed with silica sol and metal salt in coarse powder, the powder bed is soaked by the binder sprayed with glue, so that the silica sol and the metal salt are uniformly and secondarily filled in the pores of the blank, the metal salt is decomposed into metal oxide after degreasing, a shell-core structure and a crystal bridge are formed, the solid bridge between powder raw materials is strengthened, and a degreased blank with the compressive strength of 5MPa or 6MPa is obtained; the particle size of the ceramic powder ranges from 1nm to 10 mu m, and the metal salt is selected from one or more of a nitrate compound of Mg, a nitrate compound of Al, a nitrate compound of Zr, a nitrate compound of Ca, a nitrate compound of Y, a nitrate compound of Ce, a nitrate compound of Eu, a nitrate compound of La and a nitrate compound of Lu; The glue is one or more selected from epoxy resin glue, furan resin glue, acrylic ester glue, phenolic glue, polyvinyl alcohol glue, cellulose glue and sodium silicate glue.
2. 2. The method for preparing high-performance structural ceramic based on binder jetting technology according to claim 1, wherein the ceramic powder is at least one of alumina, zirconia, silicon nitride and aluminum nitride.
3. 3. The method for producing high-performance structural ceramics based on binder jetting technology according to claim 1, characterized in that the sintering aid is selected from alkaline earth metal oxides and/or rare earth metal oxides.
4. 4. The method of producing a high performance structural ceramic based on binder jetting technology according to claim 1, wherein the sintering aid is selected from one or more of MgO、Al 2 O 3 、ZrO 2 、CaO、SiO 2 、Cr 2 O 3 、Y 2 O 3 、La 2 O 3 、Ce 2 O 3 、Sm 2 O 3 、Eu 2 O 3 、Gd 2 O 3 、Lu 2 O 3 .
5. 5. The method for preparing high-performance structural ceramics based on binder jetting technology according to claim 1, wherein the particle size of the sintering aid ranges from 1nm to 10 μm.
6. 6. The method for preparing high-performance structural ceramics based on the binder spraying technology according to claim 1, wherein the mass fraction of SiO 2 in the silica sol is 1-50%, and the average particle size of SiO 2 is 1-500 nm.
7. 7. The method for preparing high-performance structural ceramics based on binder spraying technology according to claim 1, wherein in the step S2, the powder spreading thickness is 60 μm to 200 μm.
8. 8. A structural ceramic matrix core produced by binder jetting, characterized in that it is produced by the method for producing high-performance structural ceramics according to any one of claims 1 to 7, based on binder jetting technology.

Description

Method for preparing high-performance structural ceramic based on binder spraying technology Technical Field The invention relates to the technical field of additive manufacturing, in particular to a method for preparing high-performance structural ceramics based on a binder spraying technology. Background The structural ceramic is an advanced ceramic which has excellent mechanical, thermal and chemical properties such as high temperature resistance, scouring resistance, corrosion resistance, high hardness, high strength, low creep rate and the like and is commonly used for various structural components. The material used for manufacturing the structural ceramics, such as alumina, zirconia, silicon nitride and the like, has the characteristics of high strength and high hardness after sintering and molding. Additive manufacturing techniques provide new directions for the preparation of complex-shaped ceramic components. The binder injection additive manufacturing (BJAM) is based on a powder bed process, the binder is sprayed layer by layer through an ink jet printing head to be deposited on the powder bed in a selected area, green parts are formed by layer superposition, and the green parts are densified and parts with good mechanical properties are obtained through subsequent curing, degreasing and sintering processes. The BJAM technology has the characteristics of high speed, high efficiency, low cost, no need of additional support and the like, and is not only high in precision, but also suitable for the preparation of large-scale components and mass production. In order to obtain a good powder spreading effect, the BJAM technology has high requirements on powder, such as high flowability, so that near spherical powder is generally used, and the particle size ranges from 10 um to 200um. However, the powder characteristics (particle size, specific surface area, etc.) of advanced ceramic materials have a great influence on the sintering activity. In general, the smaller the particle size, the larger the specific surface, the higher the sintering activity and the lower the sintering temperature. In the preparation process of high-performance ceramics, raw materials of submicron and nanometer powder are generally adopted, and enough sintering activity is provided to ensure complete densification of the material. The sintering activity of the powder is seriously reduced by the ceramic powder with the particle size of 10-200um used by BJAM, and the powder with the particle size range is usually used as porous ceramic, heat insulation material and the like, so that the preparation of advanced ceramic with high density and high performance by adopting BJAM technology is very difficult. In addition, based on the influence of the powder bed process, the powder bed density and other aspects, such as the powder characteristics (particle size, distribution, morphology and the like), the powder laying process (powder laying mode, thickness, speed and the like), the powder bed with almost no external force effect is realized by virtue of natural accumulation, the contact points among powder particles are fewer, and pores are larger, so that the sintering of the high-performance structural ceramic is not facilitated. Disclosure of Invention The invention aims to solve the technical problem of how to prepare high-density and high-strength structural ceramics by adopting a binder injection molding technology. In order to solve the problems, the invention provides the following technical scheme: in one aspect, the invention provides a method for preparing high-performance structural ceramics based on a binder jetting technology, comprising the following steps: S1, uniformly mixing 80-99 parts by mass of ceramic powder and 1-20 parts by mass of sintering aid, adding mixed suspension containing 20-30 parts by mass of metal salt, 20-30 parts by mass of silica sol and 20-30 parts by mass of glue into the mixed powder, and granulating to prepare coarse powder, wherein the particle size of the coarse powder is 0.1-150 um, preferably 0.1-60um; S2, forming the coarse powder into blanks by using a binder spraying technology; s3, degreasing and sintering the blank to obtain a ceramic matrix core; The particle size of the ceramic powder ranges from 1nm to 10um, and the metal salt is selected from alkaline earth metal nitrate and/or rare earth metal nitrate. The particle size of the ceramic powder ranges from 1nm to 10um, preferably 100nm to 1um, and the ceramic powder has higher sintering activity under the particle size range. The mixed suspension solution is prepared by dissolving metal salt in a solvent in advance, then adding silica sol and glue, and mixing, wherein the solvent can be absolute ethyl alcohol. The granulation mode of the invention is preferably extrusion stirring granulation, the principle is shown in figure 2, specifically, after ceramic powder and sintering aid are mixed, when the mixed powder is extruded and stir