CN108285331B

CN108285331B - Ceramic pug, preparation method and application

Info

Publication number: CN108285331B
Application number: CN201810002486.0A
Authority: CN
Inventors: 孙志强; 董衡; 王华栋; 肖振兴; 秦高磊; 李淑琴; 吕毅
Original assignee: Aerospace Research Institute of Materials and Processing Technology
Current assignee: Aerospace Research Institute of Materials and Processing Technology
Priority date: 2018-01-02
Filing date: 2018-01-02
Publication date: 2020-04-21
Anticipated expiration: 2038-01-02
Also published as: CN108285331A

Abstract

The invention relates to a ceramic pug, a preparation method and application thereof. The preparation method comprises the following steps: mixing a dispersing agent, a thickening agent, ceramic powder and a plasticizer to obtain a mixture; adding an alkaline solution into the mixture while stirring; continuously stirring and then ageing to obtain ceramic pug; wherein the plasticizer is acidic silica sol, the pH is 3-6, and the concentration is 5-30 wt.%; the ceramic powder comprises particles with the particle size of 30-50 nm and particles with the particle size of 0.5-1 mu m, and the content ratio is 3-20 wt.% and 80-97 wt.%, respectively. The acidic silica sol has charges and can be adsorbed on the surface of the ceramic powder, and in the subsequent preparation steps, the alkaline solution is added while stirring, so that the dispersed sol particles are subjected to polymerization reaction to generate gel, the gel network enables the ceramic particles to be mutually crosslinked, the interaction among the particles is enhanced, the plasticity of the ceramic pug is improved, and the ceramic pug has higher solid content.

Description

Ceramic pug, preparation method and application

Technical Field

The invention relates to the technical field of ceramic materials, in particular to a ceramic pug, a preparation method and application.

Background

Ceramic materials have penetrated into many fields, and many scientific fields such as environmental protection, energy conservation, chemical industry, petroleum, smelting, food, pharmacy, biomedicine and the like are not separated from ceramic materials. Extrusion molding, press molding, tape casting and 3D printing molding are important processes for ceramic preparation, and are popular because of simplicity and low cost. However, with the development of ceramic technology and the adjustment of product structure, the proportion of the barren blank is higher and higher, especially for high-grade daily porcelain and functional ceramic, the barren blank content is up to more than 80%, so that the slurry has low plasticity and poor forming quality, and becomes a main technical obstacle influencing industrial production.

Generally speaking, the high-plasticity pug is obtained when the plasticity index is more than 15, the plasticity pug is obtained when the plasticity index is between 7 and 15, and the low-plasticity pug is obtained when the plasticity index is less than 7. From the current domestic production conditions and research situations, the addition of the plasticizer is the most effective method for obtaining the high-plasticity pug.

There are two main classes of plasticizers currently used: inorganic plasticizers and organic plasticizers. The inorganic plasticizer is mainly clay, and the organic plasticizer is polyvinyl alcohol, methyl cellulose, starch, etc. These plasticizers can adsorb and hydrate barren particles, and generate a common water film to strengthen the interaction between particles, thereby plasticizing the sludge. In order to obtain good plasticizing effect, the amount of the plasticizer is often large (the amount is generally more than 15 wt.%), and the viscosity of the plasticizer is high, so that the solid content of the pug cannot be further increased (the solid content is generally less than 60 wt.%), and the difficulty of subsequent sintering of the ceramic is increased. In addition, organic plasticizers may present environmental pollution problems during burn-off, and their residues may also degrade the functional properties of the ceramic. The measures of ball milling, particle size grading optimization, aging and the like can improve the plasticity of the ceramic pug to a certain extent, but cannot replace the function of a plasticizer.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of large using amount of the existing ceramic pug plasticizer, pollution and the like, the invention provides a novel environment-friendly plasticizing method which comprises the following steps: the interaction among the particles is strengthened through the gelation process of the sol, so that the plasticity of the ceramic pug is improved.

(II) technical scheme

In order to solve the technical problems, the invention provides the following technical scheme:

a preparation method of ceramic pug comprises the following steps:

(1) mixing a dispersing agent, a thickening agent, ceramic powder and a plasticizer to obtain a mixture;

(2) adding an alkaline solution into the mixture while stirring;

(3) continuously stirring and then ageing to obtain the ceramic pug;

wherein the plasticizer is acidic silica sol, the pH is 3-6, and the concentration is 5-30 wt.%;

the ceramic powder comprises particles with the particle size of 30-50 nm and particles with the particle size of 0.5-1 mu m, and the content ratio of the particles is 3-20 wt.% and 80-97 wt.%, respectively.

Preferably, the alkaline solution is selected from any one of an aqueous ammonia solution, an aqueous solution containing bicarbonate, an aqueous solution containing carbonate, an aqueous solution containing acetate, an aqueous solution containing citrate, or an aqueous solution containing hydroxide, preferably an aqueous ammonia solution, and more preferably an aqueous ammonia solution having a concentration of 10 to 20 wt.%. Further preferably, the mass of the alkaline solution accounts for 0.02-0.08 wt.% of the mass of the mixture;

the mass of the acidic silica sol accounts for 22-26.6 wt% of the mass of the mixture.

Preferably, the ceramic powder is alumina ceramic powder or zirconia ceramic powder, and the mass of the ceramic powder accounts for 73-77.6 wt% of the mass of the mixture.

Preferably, the dispersant is selected from any one of glycerol, phosphate ester, glycerol trioleate or triethanolamine, and accounts for 0.1-0.3 wt% of the mass of the mixture.

Preferably, the thickener is selected from any one of sodium carboxymethylcellulose, polyvinyl alcohol or polyethylene glycol, and accounts for 0.3-0.5 wt% of the mass of the mixture.

Preferably, the stirring time is not less than 30 minutes, and preferably 30-40 minutes;

the ageing time is 48-60 hours.

A ceramic pug is prepared by any one of the preparation methods. Preferably, the plasticity index of the ceramic pug is 15-18, and the solid content is 70-78 wt.%.

The ceramic pug is applied to preparing ceramic products by adopting any one of extrusion molding, compression molding, tape casting molding or 3D printing molding.

(III) advantageous effects

The technical scheme of the invention has the following advantages:

according to the invention, weakly acidic silica sol (pH is 3-6) is used as a plasticizer, and the acidic silica sol is charged, so that the acidic silica sol can be adsorbed on the surfaces of ceramic powder such as alumina and zirconia, and in the subsequent preparation steps, an alkaline solution is added while stirring, dispersed sol particles can undergo a polymerization reaction to generate gel, the gel network enables the ceramic particles to be crosslinked with each other, the interaction among the particles is enhanced, the plasticity of the ceramic pug is improved, and the ceramic pug has high solid content. Through detection, when the ceramic pug provided by the invention is adopted for 3D printing forming, the extrusion pressure is 4kg/cm²The mud can be extruded out from a nozzle with the diameter of 2mm, and the printing forming performance is good.

Drawings

FIG. 1 is a schematic flow diagram of a method for preparing ceramic pug according to the present invention;

FIG. 2 is a schematic illustration of the plasticization mechanism used in the preparation process provided by the present invention;

fig. 3 is a schematic view of the ceramic paste prepared by the present invention for 3D extrusion molding.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The invention provides a preparation method of ceramic pug, as shown in figure 1, the preparation method comprises the following steps:

(1) and mixing the dispersing agent, the thickening agent, the ceramic powder and the plasticizer to obtain a mixture. The plasticizer used in the invention is acidic silica sol, the pH is 3-6, the concentration is 5-30 wt.%, and the mass accounts for 22-26.6 wt.% of the mass of the mixture, for example, 22 wt.%, 23 wt.%, 24 wt.%, 25 wt.%, 26 wt.% or 26.6 wt.%. The invention uses weak acid silica sol (pH is 3-6) as a plasticizer, and the acid silica sol can be adsorbed on the surface of ceramic powder such as alumina, zirconia and the like because of the charge of the acid silica sol. In the subsequent preparation step, as the alkaline solution is added while stirring, the dispersed sol particles undergo a polymerization reaction to form a gel, the gel network crosslinks the ceramic particles, the interaction between the particles is enhanced, and the plasticity of the ceramic paste is improved (as shown in fig. 2). The ceramic powder comprises particles with the particle size of 30-50 nm and particles with the particle size of 0.5-1 mu m, and the content ratio of the particles is 3-20 wt.% and 80-97 wt.%, respectively. The preparation method provided by the invention can be used for plasticizing various ceramic pugs, and preferably is an alumina ceramic pug or a zirconia ceramic pug. The ceramic powder used by the alumina ceramic pug is alumina ceramic powder, the ceramic powder used by the zirconia ceramic pug is zirconia ceramic powder, and the mass of the alumina ceramic powder or the zirconia ceramic powder accounts for 73-77.6 wt% of the mass of the mixture, for example, the mass can be 73 wt%, 74 wt%, 75 wt%, 76 wt%, 77 wt% or 77.6 wt%. The dispersant used may be any one selected from glycerol, phosphate ester, glycerol trioleate or triethanolamine, and the mass of the dispersant is preferably 0.1 to 0.3wt.%, for example, specifically 0.1 wt.%, 0.2 wt.% or 0.3wt.% of the mass of the mixture. The thickener used may be any one of sodium carboxymethylcellulose, polyvinyl alcohol or polyethylene glycol, and the mass is preferably 0.3 to 0.5wt.%, for example, specifically 0.3wt.%, 0.4 wt.% or 0.5wt.% of the mass of the mixture.

(2) Adding an alkaline solution to the mixture while stirring. The alkaline solution is used for initiating local sol polymerization reaction and strengthening the interaction among particles. The alkaline solution used is selected from any one of an aqueous ammonia solution, an aqueous solution containing bicarbonate, an aqueous solution containing carbonate, an aqueous solution containing acetate, an aqueous solution containing citrate, or an aqueous solution containing hydroxide, preferably an aqueous ammonia solution, and more preferably an aqueous ammonia solution having a concentration of 10 to 20 wt.%. More preferably, the mass of the alkaline solution accounts for 0.02 to 0.08 wt.% of the mass of the mix, and may be, for example, 0.02 wt.%, 0.03 wt.%, 0.04 wt.%, 0.05 wt.%, 0.06 wt.%, 0.07 wt.%, 0.08 wt.%, or 0.09 wt.%. In this step, stirring is indispensable, and therefore, stirring is required while adding the alkaline solution to adjust the pH, and stirring is continued for 30 minutes or more, preferably 30 to 40 minutes after the alkaline solution is completely added. The uniformity of particle crosslinking can be ensured by stirring, and the uniformity of pug can be improved after the crosslinking is finished.

(3) And (3) continuously stirring for 30-40 minutes, and then ageing for 48-60 hours. After the aging is finished, the high-plasticity ceramic pug provided by the invention can be obtained.

The ceramic pug provided by the invention is prepared by adopting the preparation method. The plasticity index of the ceramic pug can reach 15-18, and the solid content can reach 70-78 wt.%.

The ceramic pug provided by the invention not only has high plasticity, but also has higher solid content and wide application range, and can be applied to the preparation of ceramic products by adopting any one of extrusion molding, press molding, tape casting or 3D printing molding.

The following are examples of the present invention.

Example 1

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 3 and the concentration of 5 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 3 wt% of particles with the particle size of 30-50 nm and 97 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together were mechanically stirred, and ammonia water was added thereto at a mass fraction of 0.08 wt.% and a concentration of 10 wt.%, to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 15 and the solid content of 75 wt.%.

Example 2

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 3 and the concentration of 5 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 8 wt% of particles with the particle size of 30-50 nm and 92 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together were mechanically stirred, and ammonia water was added thereto at a mass fraction of 0.08 wt.% and a concentration of 10 wt.%, to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 16 and the solid content of 75 wt.%.

Example 3

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 3 and the concentration of 5 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 16 wt% of particles with the particle size of 30-50 nm and 84 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together were mechanically stirred, and ammonia water was added thereto at a mass fraction of 0.08 wt.% and a concentration of 10 wt.%, to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 16.5 and the solid content of 75 wt.%.

Example 4

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 3 and the concentration of 5 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 16 wt% of particles with the particle size of 30-50 nm and 84 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together were mechanically stirred, and ammonia water was added thereto at a mass fraction of 0.08 wt.% and a concentration of 10 wt.%, to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 17 and the solid content of 75 wt.%.

Example 5

Firstly, adding 22.4 wt% of acidic silica sol with the mass fraction of 3 and the concentration of 5 wt% into 0.1 wt% of glycerol, 0.3 wt% of carboxymethyl cellulose and 77.2 wt% of ceramic powder, wherein the ceramic powder comprises 8 wt% of particles with the particle size of 30-50 nm and 92 wt% of particles with the particle size of 0.5-1 μm; then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together were mechanically stirred, and ammonia water was added thereto at a mass fraction of 0.08 wt.% and a concentration of 10 wt.%, to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 15 and the solid content of 77 wt.%.

Example 6

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 6 and the concentration of 5 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 8 wt% of particles with the particle size of 30-50 nm and 92 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together are mechanically stirred, and ammonia water with the mass fraction of 0.02 wt.% and the concentration of 10 wt.% is added to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 16 and the solid content of about 75 wt.%.

Example 7

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 6 and the concentration of 10 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 8 wt% of particles with the particle size of 30-50 nm and 92 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together are mechanically stirred, and ammonia water with the mass fraction of 0.02 wt.% and the concentration of 10 wt.% is added to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 17.5 and the solid content of 75 wt.%.

Example 8

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 6 and the concentration of 20 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 8 wt% of particles with the particle size of 30-50 nm and 92 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together are mechanically stirred, and ammonia water with the mass fraction of 0.02 wt.% and the concentration of 10 wt.% is added to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 18 and the solid content of 75 wt.%.

Example 9

Firstly, adding 24.3 wt% of acidic silica sol with the mass fraction of 24.3 wt%, the pH value of 6 and the concentration of 30 wt% into 0.1 wt% of glycerin, 0.3 wt% of carboxymethyl cellulose and 75.3 wt% of ceramic powder, wherein the ceramic powder comprises 8 wt% of particles with the particle size of 30-50 nm and 92 wt% of particles with the particle size of 0.5-1 mu m. Then, the glycerin, the carboxymethyl cellulose, the ceramic powder and the acidic silica sol mixed together are mechanically stirred, and ammonia water with the mass fraction of 0.02 wt.% and the concentration of 10 wt.% is added to initiate local sol polymerization. And then, continuously stirring for 30min to improve the uniformity of the pug. And finally, ageing for 48 hours to obtain the ceramic pug with the plasticity index of 17.5 and the solid content of 75 wt.%.

Examples 10 to 13 were prepared in substantially the same manner as in example 1 except that the differences were as shown in Table 1.

3D printing is carried out by adopting the 3D printing equipment in the figure 3, and raw materialsThe ceramic pugs prepared in examples 1 to 13 were prepared, respectively. At an extrusion pressure of 4kg/cm²Then, the ceramic pug can be extruded from a nozzle with the diameter of 2mm, and the printing and forming performance is good.

Several sets of comparative products are provided.

The ceramic pug provided in comparative example 1 was prepared as follows: mixing alumina ceramic powder (with the particle size of 30-50 mu m), glycerol, carboxymethyl cellulose and clay according to the mass ratio of 75.3:0.1:0.3: 24.3. Then, water is added to obtain the ceramic pug. The plasticity index was measured to be 11 and the solids content was measured to be 59 wt.%.

The ceramic pug provided in comparative example 2 was prepared as follows: mixing and stirring 250g of alumina ceramic powder (with the particle size of 30-50 mu m), 0.306g of ammonia water (with the concentration of 10 wt.%), and 40g of water for 30min, then adding 1.5g of agarose, and uniformly mixing to obtain the ceramic pug. The plasticity index of the composite material is 10, and the solid content of the composite material is 55 wt.%.

The ceramic pug provided in comparative example 3 was prepared as follows: mixing and stirring 250g of alumina ceramic powder (with the particle size of 30-50 mu m), 0.306g of ammonia water (with the concentration of 10 wt.%), and 40g of water for 30min, then adding 1.5g of alkaline silica sol (a commercial product), and uniformly mixing to obtain the ceramic pug. The plasticity index of the steel is 11, and the solid content of the steel is 58 wt.%.

The ceramic slip provided in comparative example 4 was prepared as follows: 1 part of alkaline silica sol (a commercial product) is dissolved in deionized water to form 0.2mol/L silica sol solution, 10 parts of zirconium nitrate is weighed and dissolved in absolute ethyl alcohol to form 0.2mol/L zirconium nitrate solution, and 0.5 part of yttrium nitrate is weighed and dissolved in absolute ethyl alcohol to form 0.2mol/L yttrium nitrate solution. The three solutions are mixed and stirred uniformly, and then 5mL of 10% nitric acid is added to adjust the pH value of the mixed solution to 5.0. And adding 0.5 part of SiC whisker and 88 parts of alumina powder into the mixed solution, and putting the mixed solution into a ball milling tank for ball milling to obtain the ceramic pug. The plasticity index of the composite material is 12, and the solid content of the composite material is 60 wt.%.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The preparation method of the ceramic pug is characterized by comprising the following steps of:

(2) adding an alkaline solution into the mixture while stirring;

(3) continuously stirring and then ageing to obtain the ceramic pug;

the ceramic powder comprises particles with the particle size of 30-50 nm and particles with the particle size of 0.5-1 mu m, and the content ratio is 3-20 wt.% and 80-97 wt.%, respectively; the alkaline solution is an ammonia water solution with the concentration of 10-20 wt.%; the mass of the alkaline solution accounts for 0.02-0.08 wt% of the mass of the mixture; the mass of the acidic silica sol accounts for 22-26.6 wt% of the mass of the mixture; the ceramic powder is alumina ceramic powder or zirconia ceramic powder, and the mass of the ceramic powder accounts for 73-77.6 wt% of the mass of the mixture.

2. The preparation method according to claim 1, wherein the dispersant is selected from any one of glycerol, phosphate ester, glycerol trioleate or triethanolamine, and accounts for 0.1-0.3 wt.% of the mass of the mixture.

3. The preparation method according to claim 1, wherein the thickener is selected from any one of carboxymethyl cellulose, polyvinyl alcohol or polyethylene glycol, and accounts for 0.3-0.5 wt.% of the mass of the mixture.

4. The preparation method according to claim 1, wherein stirring is continued after the alkaline solution is completely added, and the stirring time is 30 to 40 minutes;

the ageing time is 48-60 hours.

5. A ceramic pug, characterized in that it is prepared by the process of any one of claims 1 to 4.

6. Ceramic slip as claimed in claim 5, characterized in that it has a plasticity index of 15 to 18 and a solid content of 70 to 78 wt.%.

7. Use of the ceramic pug of claim 5 or 6 in the preparation of ceramic products by any one of extrusion, compression molding, tape casting or 3D printing.