CN100503515C - Method of preparing functional ceramic material - Google Patents

Abstract

The invention discloses a preparation method of functional ceramics material and comprises the steps: (1) suspending liquid containing organic monomer, cross linker, evocating agent, dispersant and ceramics powder lot is prepared; (2) catalyst is added, slurry is injected into a ring mental die to be solidified in situ and wet rough-body of large size ceramics is obtained; (3) after being demoulded, the rough-body is put into a net clamp, the clamp is put into a climatic chamber to be dried and then put into an oven to be dried after a plurality of days; (4) the dried rough-body is batched out under certain temperature rising system and sintered into ceramics under high temperature. The invention prepares large size high performance lead zinc niobate-lead zirconate titanate piezoceramics, barium strontium titanate pyroelectric ceramics, lead manganese niobate-lead manganese stibate-lead zirconate titanate pyroelectric ceramics.

Description

A kind of method for preparing ceramic material

Technical field

The present invention relates to prepare the method for ceramic material, this method adopts water-base gel casting and netted anchor clamps desiccating method to prepare large size performance function stupalith.

Background technology

The through engineering approaches technology of preparing of large size function ceramics is the technical barrier that numerous in recent years investigators pay close attention to, reason owing to size, this based article each link in preparation process all has the difficulty more much higher than small sized article, mainly is: the homogeneity of molding blank integral body is difficult to realize; Molding blank intensity is low, is difficult for guaranteeing its be not damaged (distortion or cracking) in technological process subsequently; Each process procedure is difficult to realize steady, consistent evolution or the like the process from the powder state to end article.

Based on this, the gel casting forming technology (gel-casting) of Chu Xianing is used among the preparation technology of large-size ceramic in recent years, gel-casting technology is U.S. Oak Tree National Laboratory in the ceramic dead size forming technique of a kind of novelty of eighties of last century invention at the end of the nineties (referring to A.C.Young, O.O.Omatete, M.A.Janney, P.A.Menchhofer, Gelcasting of alumina, J.Am.Ceram.Soc.74 (3) (1991) 612-618).This technology combines traditional grouting process and polymer chemistry, utilizes fixedly ceramic powder of organic monomer in-situ polymerization, and slurry mold filling process and mixture solidified process are separately carried out.Its ultimate principle is at high solid loading, in the low viscous ceramic size, the organic monomer that mixes lower concentration is (as acrylamide AM, Methacrylamide MAM, vinyl pyrrole ketone NVP, methyl polyethyleneglycol methacrylic ester MPEGMA or the like) and linking agent (as methylene-bisacrylamide MBAM), when adding a spot of initiator (as ammonium persulphate) and catalyzer (as N, N, N, the N-Tetramethyl Ethylene Diamine) and the casting after, home position polymerization reaction takes place in the organic monomer in the slurry under certain temperature condition, form firm tridimensional network, thereby make the moulding of suspensoid in-situ solidifying, obtain evenly, high strength, the ceramic body of accurate dead size.Carry out the demoulding, drying, removal organism, sintering then, can make required ceramic part.Gel-casting technology remarkable advantage is a slurry solid load height, and the whole homogeneity of its molding blank is better than compression molding.But when preparing the large size function ceramics with Gel-casting, because water ratio is with respect to the compression molding height, size is very big, in drying process, the drying rate at each position does not wait, and is easy to cause ceramic body bending and cracking, if the maintenance homogeneity, and the drying rate that slows down then can be grown to one month even two months time of drying.By the lot of documents retrieval, do not find to prepare in conjunction with netted anchor clamps desiccating method the report of large size function ceramics with the gel casting forming technology.

Summary of the invention

The object of the present invention is to provide a kind of method for preparing ceramic material, this method can guarantee the homogeneity of large size body drying process, shortens time of drying, prevents the distortion and the cracking of base substrate.

The method for preparing ceramic material provided by the invention, step comprises:

(1), functional ceramic powder is mixed the formation mixed solution with premixed liquid, the powder volume accounts for 40～60vol% of total mixeding liquid volume, premixed liquid is the mixture of acrylamide and methylene-bisacrylamide and deionized water, the concentration of premixed liquid is 15～20wt%, and the mass ratio of acrylamide and methylene-bisacrylamide is 16～24:1;

(2), in above-mentioned mixed solution, add dispersion agent and initiator, dispersion agent is that concentration is the ammonium polymethacrylate solution of 8～18wt%, add-on is 0.4～1.2wt% of ceramic powder quality in the mixed solution, initiator is the ammonium persulfate solution of concentration 3～6wt%, and add-on is 0.4～0.6wt% of premixed liquid quality in the mixed solution;

(3), adopted the planetary ball mill ball milling 2～4 hours, the acquisition ceramic size;

(4) ceramic size is put into the ultrasonic de-bubble of ultrasonic cleaning machine 3～5 minutes, added catalyzer, catalyzer is N, N, N, N-Tetramethyl Ethylene Diamine, add-on is 0.2～0.3wt% of premixed liquid quality in the mixed solution, again slurry is injected mould, and this mould is stained with the sheet glass of metal ring for the surface;

(5), mould was placed in the air after 24～48 hours, netted anchor clamps are put in the base demoulding of will wetting, and anchor clamps are placed in the climatic chamber dry back again and take out, and controlling moisture is by 95% to 65% in the drying process, and controlled temperature is by 10 ℃ to 30 ℃;

(6), base substrate that drying is good is at 600 ℃～700 ℃ following binder removals, binder removal speed is less than 20 ℃/hour, high temperature sintering becomes porcelain again.

The present invention utilizes the water-base gel casting technology to prepare large size performance function pottery, utilize a kind of netted anchor clamps dry base substrate on this basis, and place climatic chamber, guarantee the homogeneity of large size body drying process, shortened time of drying, prevent the distortion and the cracking of base substrate, thereby prepared the performance function pottery of large size, good uniformity.Adopting the inventive method can prepare large size high-performance lead zinc niobate-lead titanate piezoelectric ceramics, barium strontium titanate pyroelectric ceramics, manganese niobium lead acid-antimony mangaic acid lead-Pb-based lanthanumdoped zirconate titanates is pyroelectric ceramics etc.

Description of drawings

Fig. 1 is the gel injection molding and forming technology schema

Fig. 2 is the SEM figure of lead zinc niobate-Pb-based lanthanumdoped zirconate titanates;

Fig. 3 is the SEM figure of manganese niobium lead acid-antimony mangaic acid lead-Pb-based lanthanumdoped zirconate titanates;

Fig. 4 is the SEM figure of barium-strontium titanate ceramic;

Fig. 5 is Jie's temperature curve of barium-strontium titanate ceramic.

Embodiment

The present invention adopts the mould that can come off of going to the bottom so that the demoulding of the wet base of large-size ceramic, and adopt netted anchor clamps drying, because in the process of preparation large-size ceramic, drying process is a technical barrier, because the size of pottery is bigger, the humiture difference of surperficial environment causes pottery to be easy to distortion and cracking, and netted anchor clamps have not only guaranteed the homogeneity of ceramic upper and lower surface environment, and the pressure of anchor clamps can prevent the distortion of pottery, thereby obtains large size, uniform base substrate.

The schema of the inventive method below by specific examples, further specifies characteristics of the present invention and effect as shown in Figure 1:

Example 1:

Water-base gel casting prepares large size 0.15 (PbZn in conjunction with netted anchor clamps desiccating method _1/3Nb _2/3O ₃)+0.85[Pb (Zr _0.54Ti _0.46) O ₃] piezoelectric ceramics.

Concrete technology is:

(1) presses chemical formula, prepare the PZN-PZT powder with solid-phase synthesis;

(2) with 500g powder and 65.8ml premixed liquid, 25g dispersion agent and 1.75g initiator mixing and ball milling 2 hours, preparing solid load was that 50vol%, viscosity are the slurry of 90mPas;

(3) pour out slurry, add catalyzer 0.8g, pour in the annular die of Φ 21cm, mould is for the surperficial sheet glass that is stained with metal ring, so that the demoulding;

(4) mould is placed on the demoulding after 24 hours in the air, puts into netted anchor clamps, wherein netted anchor clamps are that two length of sides are the square woven wire of 25cm, and four limits are fixed with steel bar, at four screw holes of four angular bits of steel bar two steel meshes are clipped together again; Anchor clamps are put into climatic chamber, in 10 ℃ of humidity 95%, temperature, placed three days, be adjusted to then in 25 ℃ of the humidity 80%, temperature and placed two days, be adjusted to again in 30 ℃ of the humidity 65%, temperature and placed three days;

(5) drying is good base substrate is at 700 ℃ of following binder removals, and binder removal speed is 16 ℃/h; And sinter porcelain at 1230 ℃.

Pottery is of a size of Φ 16cm behind the sintering, and density is 7.4g/cm ³In order to test the homogeneity of large-size ceramic, with pottery cut into 32 samples (area is 1.5cm * 1.5cm), coat silver electrode, tests its specific inductivity and dielectric loss respectively, result such as table one:

Table one

Numbering	Thickness (mm)	Electric capacity (pF)	Loss (‰)	Specific inductivity
					1	2.30	711	4.6	820
2	2.26	746	6.2	846
					3	2.44	689	3.8	843
4	2.22	724	6.6	807
					5	2.40	631	4.6	760
6	2.18	708	5.4	774
					7	1.92	807	5.8	774
8	2.36	674	3.9	799
					9	2.48	621	4.5	772
10	2.54	648	5.2	825
					11	2.32	698	5.9	812
12	2.36	655	4.4	775
					13	2.68	582	5.6	782
14	2.30	711	6.7	820
					15	2.30	682	6.2	787
16	2.50	673	4.8	798
					17	2.48	612	5.6	761
18	2.46	680	3.8	839
					19	2.4	695	4.1	837
20	2.3	700	7.7	773
					21	2.20	763	3.5	842

22	1.96	855	2.7	840
					23	2.26	722	5.4	818
24	2.24	685	3.5	770
					25	2.30	724	3.7	836
26	1.98	837	4.2	831
					27	1.86	896	4.4	837
28	2.14	775	4.8	832
					29	2.16	770	3.8	834
30	2.06	737	3.6	762
					31	2.40	698	4.1	840
32	2.28	722	4.6	826

Can be calculated by above chart: the average dielectric constant of this ceramic plate is 808, and dielectric loss is 0.5

%, the specific inductivity homogeneity is 5.6%.Its SEM figure as shown in Figure 2.

Example 2:

Water-base gel casting prepares large size in conjunction with netted anchor clamps desiccating method

Pb[(Mn _0.3Nb _0.7) _1/2(Mn _0.3Sb _0.7) _1/2] _0.2(Zr ₉₅Ti ₅) _0.8O ₃Pyroelectric ceramics.Press chemical formula, prepare powder with solid-phase synthesis, sintering temperature is 1240 ℃, and other are with example 1, and pottery is of a size of Φ 15.8cm behind the sintering, and density is 7.51g/cm ³, adopting its specific inductivity of test that uses the same method is 251, and dielectric loss is 4%, and pyroelectric coefficient is 7.5 * 10 ^-4C/m ²℃ (30 ℃), the specific inductivity homogeneity is 4.8%, its SEM figure is as shown in Figure 3.

Example 3:

Water-base gel casting prepares large size Ba in conjunction with netted anchor clamps desiccating method _0.7Sr _0.3TiO ₃Pyroelectric ceramics.

Concrete technology is:

(1) presses chemical formula, prepare the BST powder with solid-phase synthesis;

(2) with 300g powder and 50ml premixed liquid, 15g dispersion agent and 1.35g initiator mixing and ball milling 2 hours, preparing solid load was that 48vol%, viscosity are the slurry of 110mPas;

(3) pour out slurry, add catalyzer 0.7g, inject mould, and pour in the mould of Φ 16cm;

(4) mould is placed on the demoulding after 24 hours in the air, put into netted anchor clamps, anchor clamps are put into climatic chamber, in 10 ℃ of humidity 95%, temperature, placed three days, be adjusted to then in 25 ℃ of the humidity 80%, temperature and placed two days, be adjusted to again in 30 ℃ of the humidity 65%, temperature and placed three days;

(5) drying is good base substrate is at 700 ℃ of following binder removals, and binder removal speed is 20 ℃/h; And sinter porcelain at 1360 ℃,

(6) coat silver electrode, test its electrical property.

Pottery is of a size of 13.5cm behind the sintering, and density is 5.48g/cm ³, its SEM as shown in Figure 4, it is situated between warm curve as shown in Figure 5, its loss and pyroelectric coefficient are respectively 2% and 40 * 10 at the Curie temperature place ^-4C/m ²℃.

Claims (1)

1, a kind of method for preparing ceramic material, step comprises:

(1), functional ceramic powder is mixed the formation mixed solution with premixed liquid, the powder volume accounts for 40～60vol% of total mixeding liquid volume, premixed liquid is the mixture of acrylamide and methylene-bisacrylamide and deionized water, the concentration of premixed liquid is 15～20wt%, and the mass ratio of acrylamide and methylene-bisacrylamide is 16～24:1;

(2), in above-mentioned mixed solution, add dispersion agent and initiator, dispersion agent is that concentration is the ammonium polymethacrylate solution of 8～18wt%, add-on is 0.4～1.2wt% of ceramic powder quality in the mixed solution, initiator is the ammonium persulfate solution of concentration 3～6wt%, and add-on is 0.4～0.6wt% of premixed liquid quality in the mixed solution;

(3), adopted the planetary ball mill ball milling 2～4 hours, the acquisition ceramic size;

(4) ceramic size is put into the ultrasonic de-bubble of ultrasonic cleaning machine 3～5 minutes, added catalyzer, catalyzer is N, N, N, N-Tetramethyl Ethylene Diamine, add-on is 0.2～0.3wt% of premixed liquid quality in the mixed solution, again slurry is injected mould, and this mould is stained with the sheet glass of metal ring for the surface;

(5), mould is placed in the air after 24～48 hours, netted anchor clamps are put in the base demoulding of will wetting, and wherein netted anchor clamps are that two length of sides are the square woven wire of 25cm, four limits are fixed with steel bar, at four screw holes of four angular bits of steel bar two steel meshes are clipped together again; Anchor clamps are placed on dry back taking-up in the climatic chamber, controlling moisture is by 95% to 65% in the drying process again, and controlled temperature is by 10 ℃ to 30 ℃;

(6), base substrate that drying is good is at 600 ℃～700 ℃ following binder removals, binder removal speed is less than 20 ℃/hour, high temperature sintering becomes porcelain again.

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