CN108484131B

CN108484131B - Alumina ceramic slurry suitable for 3D printing, preparation method and application

Info

Publication number: CN108484131B
Application number: CN201810104663.6A
Authority: CN
Inventors: 董衡; 孙志强; 肖振兴; 李淑琴; 吕毅; 赵英民; 裴雨辰
Original assignee: Aerospace Research Institute of Materials and Processing Technology
Current assignee: Aerospace Research Institute of Materials and Processing Technology
Priority date: 2018-02-02
Filing date: 2018-02-02
Publication date: 2020-10-16
Anticipated expiration: 2038-02-02
Also published as: CN108484131A

Abstract

The invention provides alumina ceramic slurry suitable for 3D printing, which comprises the following raw materials in percentage by mass: 70-80% of ceramic powder; 15% -25% of alumina sol; 2 to 5 percent of aluminum dihydrogen phosphate; 0.3 to 0.5 percent of dispersant; wherein the ceramic powder comprises alumina. By applying the technical scheme provided by the invention, the technical problems that in the prior art, the consumption of plasticizer required by the ceramic slurry for 3D printing is large, the environment is polluted, the strength of the prepared ceramic part is low, and the required sintering temperature is high are solved.

Description

Alumina ceramic slurry suitable for 3D printing, preparation method and application

Technical Field

The invention belongs to the technical field of functional ceramic preparation, particularly relates to functional ceramic slurry suitable for 3D printing, a preparation method and application, and particularly relates to alumina ceramic slurry suitable for 3D printing, a preparation method and application.

Background

The alumina ceramic has the properties of high mechanical strength, high resistivity, good electrical insulation, high melting point, good corrosion resistance, excellent chemical stability and the like, and is widely applied to the fields of machinery, electronic and electric power, chemical industry, medicine, building and other high-tech fields. The preparation method mainly comprises the following steps: extrusion molding, dry pressing molding, injection molding, isostatic pressing molding, tape casting, slip casting, gel casting, and the like. When the components are prepared by the processes, molds with corresponding shapes need to be prepared according to the shapes of the components, if the structures of the components are slightly changed, the molds need to be prepared again or samples need to be machined, and therefore, the preparation cost is increased.

With the development of industry, these conventional molding processes have not been able to meet the requirements of some special fields. Different from the traditional material reduction manufacturing technology, the 3D printing ceramic has the advantages of short manufacturing period, low cost, convenience in processing, strong operability and the like, and the 3D printing ceramic is currently usedPreparation of Al₂O₃The ceramic method mainly selects a laser sintering technology, a photocuring forming technology, an ink-jet printing forming technology and a three-dimensional printing forming technology. The selective laser sintering technology has the defects of high laser power required by processing, high sintering difficulty, high energy consumption and the like; the photosensitive resin mixed liquid used by the photocuring molding technology is an irritant material with toxicity and needs to be preserved in a dark place; the ink-jet printing forming technology has the defects of low solid content, incapability of accurately controlling micro-directionality, shape and concentration consistency of ink, blockage of a printing head and the like, the three-dimensional printing forming technology has the advantages of low cost, no toxicity and the like and is the most ideal printing technology for preparing alumina ceramics at present, dextrin (Tubio CR, RSC Advances 6(3), 2016), polyethylene glycol (Liujiayuan, Shanghai institute of Electrical Power, 31 (4): 2015) and clay and the like are mostly adopted as plasticizers in the slurry adopting the three-dimensional printing forming technology at present, the consumption of the plasticizer required by the ceramic slurry is large, the environment is polluted, and the prepared ceramic part has the defects of low strength, high sintering temperature and the like.

Disclosure of Invention

The invention provides an alumina ceramic slurry suitable for 3D printing, a preparation method and application, and can solve the technical problems that in the prior art, the ceramic slurry for 3D printing needs a large amount of plasticizer and pollutes the environment, and the prepared ceramic part is low in strength and high in required sintering temperature.

The technical solution of the invention is as follows:

on one hand, the invention provides alumina ceramic slurry suitable for 3D printing, which comprises the following raw materials in percentage by mass:

wherein the ceramic powder comprises alumina.

Further, in the invention, the aluminum sol is acidic aluminum sol, and the concentration of the acidic aluminum sol is 10-40 wt.%; the pH value of the acidic aluminum sol is 2-5.

Further, in the invention, the concentration of the aluminum hydrogen phosphate is 10-15 wt.%, and the pH value is 2-3.

Further, in some embodiments, the ceramic powder further comprises a nano-oxide in addition to the aluminum oxide, and the nano-scale oxide is at least one selected from nano-silica, nano-titania, and nano-copper oxide.

Further, in some embodiments, the ceramic powder has a ratio of the nano oxide to the alumina of 5% to 15% and 85% to 95% by mass, respectively.

Further, in some embodiments, the alumina has a particle size of 0.5 to 2 μm; the particle size of the nano oxide is 20-80 nm.

Further, in some embodiments, the dispersant is selected from at least one of glycerol, carboxymethylcellulose 1750, polyethylene glycol 400, polyvinyl alcohol 2000.

On the other hand, the method does not provide the preparation method of the alumina ceramic slurry suitable for 3D printing, which is realized by the following steps:

the ceramic powder, the alumina sol, the aluminum dihydrogen phosphate and the dispersant in the formula amount are mixed uniformly in sequence, and ball milling and ageing are carried out to obtain ceramic slurry with certain plasticity and fluidity.

Further, in some embodiments, the ball milling time is 20-30 min, and the staling time is 24-48 h.

Further, in the invention, the prepared ceramic slurry has plasticity and fluidity, and can be regulated and controlled within a certain range by changing the concentrations of the aluminum sol and the aluminum dihydrogen phosphate so as to meet different application requirements.

Further, the present invention also provides applications of the alumina ceramic slurry suitable for 3D printing, for example, the alumina ceramic slurry can be directly formed into an article, such as a ceramic device, by using a 3D printing technology; or preparing and molding the alumina ceramic slurry into an alumina additive, and further preparing the alumina additive into a ceramic material, for example, preparing the alumina additive by screw extrusion molding.

According to the technical scheme, the invention provides the alumina ceramic slurry suitable for 3D printing, the preparation method and the application, most of the existing plasticizers suitable for the alumina 3D printing slurry are clay or organic substances, and the plasticizers strengthen the interaction among particles through the adsorption and hydration of barren particles, so that the slurry modification is realized. In order to obtain a good plasticizing effect, the dosage of the plasticizers is often large, and the solid content of the slurry cannot be further improved due to the high viscosity of the plasticizers, so that the difficulty of subsequent sintering of the ceramic is increased; in addition, the organic plasticizer may cause environmental pollution during burning off, the residue of the organic plasticizer also reduces the functional characteristics of the ceramic, and the clay plasticizer has complicated mineral causes and uneven composition, and shows great differences in properties such as plasticity, thixotropy, binding property, contractibility, refractoriness and the like, so that the ceramic blank formula and the process of each ceramic production area are different. Although the measures of ball milling, particle size grading optimization, aging and the like can improve the plasticity of the ceramic slurry to a certain extent, the measures cannot replace the function of a plasticizer.

According to the invention, the cementation effect among particles and the water retention property of the nano ceramic powder are enhanced through the gel plasticizing process of the aluminum sol and the aluminum dihydrogen phosphate, so that the plasticity and the fluidity of the ceramic slurry are improved, the defects of the existing slurry suitable for 3D printing of aluminum oxide are overcome, the using amount of the nano ceramic powder is greatly reduced compared with that of the existing plasticizer, the problem of environmental pollution is avoided, the sintering temperature of the ceramic part is reduced, and the prepared ceramic part has higher strength. The invention uses weak acid aluminum sol which has charges and can be adsorbed on the surfaces of ceramic powder such as aluminum oxide, nano silicon dioxide, nano titanium dioxide, nano copper oxide powder and the like; and then aluminum dihydrogen phosphate is added, the dispersed sol particles can generate polymerization reaction, and the gel network enables the ceramic particles to be mutually crosslinked, so that the plasticity of the ceramic slurry is improved. It is worth noting that ball milling is needed in slurry pH adjustment to ensure uniformity of particle cross-linking, and the addition of nano silicon oxide, nano copper oxide and nano titanium oxide not only changes water retention of slurry but also reduces sintering temperature of alumina,improve the mechanical, thermal and electrical properties of the alumina ceramic. At an extrusion pressure of 6kg/cm²The slurry can be extruded from a nozzle with the diameter of 1mm, and the printing forming performance is good.

Detailed Description

The following provides a detailed description of specific embodiments of the present invention. In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details.

Example 1

Firstly, 0.3 percent of glycerol, 0.1 percent of polyvinyl alcohol 2000 and 76.8 percent of ceramic powder are added into 20 percent of acidic alumina sol with the mass fraction of 20 percent, the pH value of 3 and the concentration of 20 percent, wherein the ceramic powder contains 5 percent of 20-80 nm silicon dioxide and 95 percent of 0.5-2 mu m alumina; then adding aluminum dihydrogen phosphate with the mass fraction of 2.8%, the pH value of 2.5 and the concentration of 12% and carrying out ball milling for 20min to initiate local sol polymerization reaction and improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 48 h.

Example 2

Firstly, 0.2 percent of glycerol, 0.3 percent of polyethylene glycol 400 and 75 percent of ceramic powder are added into acid alumina sol with the mass fraction of 21 percent, the pH value of 2.8 and the concentration of 25 percent according to the mass ratio, wherein the ceramic powder comprises 10 percent of silica with the particle size of 20-80 nm and 90 percent of alumina with the particle size of 0.5-2 mu m; then adding 3.5 mass percent of aluminum dihydrogen phosphate with the pH value of 2 and the concentration of 15 percent, ball-milling for 30min to initiate local sol polymerization reaction and improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 36 h.

Example 3

Firstly, 0.2% of glycerol, 0.2% of carboxymethyl cellulose 1750 and 75.9% of ceramic powder are added into acidic alumina sol with the mass fraction of 20%, the pH value of 4 and the concentration of 15% according to the mass ratio, wherein the ceramic powder comprises 25% of 20-80 nm silicon dioxide and 75% of 0.5-1 mu m aluminum oxide; then adding 3.7 mass percent of aluminum dihydrogen phosphate with the pH of 2.2 and the concentration of 15 percent, performing ball milling for 10min to initiate local sol polymerization reaction and improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 48 h.

Example 4

Firstly, 0.1% of glycerol, 0.3% of carboxymethylcellulose 1750 and 76% of ceramic powder are added into acid alumina sol with the mass fraction of 20%, the pH value of 3 and the concentration of 35% according to the mass ratio, wherein the ceramic powder comprises 20-80 nm of silicon dioxide and 80% of 0.5-1 mu m of aluminum oxide; then adding 3.6 mass percent of aluminum dihydrogen phosphate with the pH value of 2.2 and the concentration of 14 percent, ball-milling for 20min to initiate local sol polymerization reaction and improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 24 h.

Example 5

Firstly, 0.1% of glycerol, 0.3% of carboxymethylcellulose 1750 and 75.1% of ceramic powder are added into acidic alumina sol with the mass fraction of 21%, the pH value of 2.8 and the concentration of 25% according to the mass ratio, wherein the ceramic powder comprises 10% of 20-80 nm silicon dioxide and 90% of 0.5-2 mu m aluminum oxide; then adding aluminum dihydrogen phosphate with the mass fraction of 3.5%, the pH value of 2.3 and the concentration of 15% and carrying out ball milling for 30min to initiate local sol polymerization reaction and improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 36 h.

Example 6

Firstly, 0.4 percent of polyethylene glycol 400 and 75.9 percent of ceramic powder are added into acid alumina sol with the mass fraction of 20 percent, the pH value of 4 and the concentration of 15 percent according to the mass ratio, wherein the ceramic powder comprises 25 percent of silica with the particle size of 20-80 nm and 75 percent of alumina with the particle size of 0.5-2 mu m; then adding 3.7 mass percent of aluminum dihydrogen phosphate with the pH value of 2.1 and the concentration of 14 percent, performing ball milling for 10min to initiate local sol polymerization reaction and improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 24 h.

Example 7

Firstly, 0.1% of glycerol, 0.4% of carboxymethylcellulose 1750 and 70% of ceramic powder are added into acidic alumina sol with the mass fraction of 24.5%, the pH value of 5 and the concentration of 10% according to the mass ratio, wherein the ceramic powder comprises 15% of 20-80 nm silicon dioxide and 85% of 0.5-2 mu m aluminum oxide; then adding aluminum dihydrogen phosphate with the mass fraction of 5%, the pH value of 2 and the concentration of 15% and carrying out ball milling for 25min to initiate local sol polymerization reaction and improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 48 h.

Comparative example 1

Firstly, 3% of glycerol, 8% of polyvinyl alcohol 2000 and 69% of ceramic powder are added into deionized water with the mass fraction of 20%, wherein the ceramic powder comprises 5% of silica with the particle size of 20-80 nm and 95% of alumina with the particle size of 0.5-2 microns; ball milling for 20min to improve the uniformity of the slurry; and finally, ageing for 48 h. The alumina slurry obtained in this comparative example and the properties of its product are shown in table 1.

Comparative example 2

Firstly, 35% of clay and 35% of ceramic powder are added into deionized water with the mass fraction of 30% according to the mass ratio, wherein the ceramic powder comprises 10% of 20-80 nm silicon dioxide and 90% of 0.5-2 mu m aluminum oxide; ball milling is carried out for 30min to improve the uniformity of slurry; finally, the alumina slurry obtained in this example and the properties of the product thereof are shown in table 1 after aging for 36 h.

Table 1 results of performance test of examples and comparative examples

From table 1, it can be seen that the highest interlayer bonding strength of the sintered ceramic of the alumina slurry suitable for 3D printing provided by the present invention can reach 80Mpa, and the ceramic is suitable for 3D printing from the viewpoint of plasticity index; while comparative example 1 shows that: under the condition of the same plasticity index, the addition amount of organic matters is large, silica sol is not used as a solvent, and the interlayer bonding strength after sintering is poor; similarly, comparative example 2 used clay as a plasticizer in a larger amount, and the final interlayer bonding strength was also greatly different.

Features that are described and/or illustrated above with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The many features and advantages of these embodiments are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of these embodiments which fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the embodiments of the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope thereof.

The invention has not been described in detail and is in part known to those of skill in the art.

Claims

1. The alumina ceramic slurry suitable for 3D printing is characterized by comprising the following raw materials in percentage by mass:

70-80% of ceramic powder;

15% -25% of alumina sol;

2 to 5 percent of aluminum dihydrogen phosphate;

0.3 to 0.5 percent of dispersant;

wherein the ceramic powder comprises alumina; the aluminum sol is acidic aluminum sol, and the pH value of the acidic aluminum sol is 2-5; the concentration of the acidic aluminum sol is 10-40 wt.%; the concentration of the aluminum dihydrogen phosphate is 10-15 wt.%, and the pH value is 2-3; besides alumina, the ceramic powder also comprises at least one nanoscale oxide selected from nanometer silicon dioxide, nanometer titanium dioxide and nanometer copper oxide; in the ceramic powder, the proportion of the nano-scale oxide to the alumina is 5-15% and 85-95% respectively by mass.

2. The alumina ceramic slurry suitable for 3D printing according to claim 1, wherein the alumina has a particle size of 0.5-2 μm; the particle size of the nano-scale oxide is 20-80 nm.

3. The alumina ceramic slurry suitable for 3D printing according to claim 1, wherein the dispersant is at least one selected from glycerol, carboxymethyl cellulose 1750, polyethylene glycol 400, and polyvinyl alcohol 2000.

4. The method of preparing an alumina ceramic slurry suitable for 3D printing according to any one of claims 1 to 3, characterized by being carried out by:

5. The method of preparing an alumina ceramic slurry suitable for 3D printing according to claim 4, wherein: the ball milling time is 20-30 min, and the staling time is 24-48 h.

6. Use of the alumina ceramic slurry suitable for 3D printing according to any one of claims 1 to 3, wherein (1) the alumina ceramic slurry is directly formed into an article using 3D printing techniques; or (2) preparing and molding the alumina ceramic slurry into an alumina additive, and further preparing a ceramic material.