Method for preparing BST-MgO (barium strontium titanate-magnesium oxide) based ceramic tape-casting slurry and blanks

A magnesia-based ceramics, casting slurry technology, applied in the field of electronic materials, can solve the problems affecting the electrical properties of the sintered body, the uneven microstructure of the green sheet, and the increase of the viscosity of the slurry, so as to achieve uniform and dense microstructure and suitable strength. , the effect of suppressing the reaction

Inactive Publication Date: 2012-04-11
TIANJIN UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In addition, in order to achieve low-temperature sintering of BST-MgO composite ceramics, B 2 o 3 -Li 2 CO 3 is a sintering aid, however B 2 o 3 The introduction of BST-MgO multiphase ceramics brought many difficulties to the casting method, for example, in the process of preparing the casting slurry, the B dissolved in the solvent 2 o 3 It reacts with hydroxyl-containing organic additives (PVA, PVB, etc.) to form a three-dimensional gel structure, which increases the viscosity of the slurry and reduces the stability, resulting in uneven microstructure of the green sheet after casting, which will eventually affect the sintered body. electrical properties

Method used

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  • Method for preparing BST-MgO (barium strontium titanate-magnesium oxide) based ceramic tape-casting slurry and blanks
  • Method for preparing BST-MgO (barium strontium titanate-magnesium oxide) based ceramic tape-casting slurry and blanks
  • Method for preparing BST-MgO (barium strontium titanate-magnesium oxide) based ceramic tape-casting slurry and blanks

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1. Casting powder pretreatment:

[0023] (1) Use an electronic balance to weigh 30gBST, 30gMgO, 0.45gB 2 o 3 and 2.25gLi 2 CO 3 .

[0024] (2) Put the weighed powder into a ball mill jar, add 110 ml of ethanol and 150 zirconia grinding balls, and use a planetary ball mill for 4 hours.

[0025] (3) Put the ball-milled slurry into a tray, put it into an oven, and dry it at 80°C.

[0026] (4) Grinding the dried powder and passing through a 100-mesh sieve.

[0027] (5) The powder is put into an electric furnace, and calcined at a temperature of 700° C., with a heating rate of 3° C. / minute, and kept for 2 hours.

[0028] 2. Preparation of cast slurry

[0029] (1) Use an electronic balance to weigh 11.19g ethanol and 27.975g xylene solution and mix them evenly, then add 0.525gPVB to the mixed solution, ultrasonic treatment for 20 minutes, after the PVB dissolves, add 30g casting powder, and use planetary Ball milling for 4 hours. A primary casting slurry with a visco...

Embodiment 2

[0036] 1. Casting powder pretreatment:

[0037] The preparation process steps are the same as in Example 1, except that the powder ball milling time in (2) is 5 hours, the calcination temperature in (5) is 750° C., and the holding time is 1.5 hours.

[0038] 2. Preparation of cast slurry

[0039] (1) Weigh 11.04g of ethanol and 16.56g of butanone solution with electronic balance and mix them evenly, then add 0.3g of PVB to the mixed solution, ultrasonic treatment for 20 minutes, after the PVB is dissolved, add 30g of casting powder, and use planetary Ball milling for 4 hours. A primary casting slurry with a viscosity of 20 mPa·s was obtained.

[0040](2) Add 1.2gPVB binder, 0.45gPEG and 0.45gDBP to the primary casting slurry, and use a rolling ball mill for ball milling for 24 hours, and finally age the slurry for 50 hours to obtain a flow that exhibits shear thinning fluid characteristics Extension slurry.

[0041] 3. Preparation of cast blanks

[0042] (1) Pour the aged...

Embodiment 3

[0046] 1. Casting powder pretreatment:

[0047] The preparation process steps are the same as in Example 1, except that the powder ball milling time in (2) is 6 hours, the calcination temperature in (5) is 800° C., and the holding time is 1 hour.

[0048] 2. Preparation of cast slurry

[0049] (1) Use electronic balance to weigh 11.34g ethanol and 17.01g butanone solution and mix them evenly, then add 0.6gPVB to the mixed solution, ultrasonic treatment for 20 minutes, after PVB dissolves, add 30g casting powder, and use planetary Ball milling for 4 hours. A primary casting slurry with a viscosity of 20 mPa·s was obtained.

[0050] (2) Add 0.6gPVB binder, 0.225gPEG and 0.225gDBP to the primary casting slurry, and use a rolling ball mill for ball milling for 24 hours, and finally age the slurry for 16 hours to obtain a flow that exhibits shear thinning fluid characteristics Extension slurry.

[0051] 3. Preparation of cast blanks

[0052] (1) Pour the aged final tape castin...

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Abstract

The invention relates to a method for preparing BST-MgO (barium strontium titanate-magnesium oxide) based ceramic tape-casting slurry and blanks, which is characterized in that through the selection of organic additives and the pretreatment of powder and the like, the reaction between B2O3 and PVB in a formula is restrained, then, a tape-casting slurry system which is moderate in viscosity and good in liquidity is obtained, and finally, a BST-MgO tape-casting blank which is good in structure and performance is prepared. The method provided by the invention is implemented according to the following technical scheme: through taking ethanol-xylene as a solvent, polyvinyl butyral (PVB) as an adhesion agent, polyethylene glycol (PEG) as a dispersant and dibutyl phthalate (DBP) as a plasticizer, BST-MgO based tape-casting slurry taking B2O3-Li2CO3 as a sintering assistant is prepared, and finally, a high-quality tape-casting blank is formed for laying an application foundation for LTCC (low temperature co-fired ceramic) devices. The slurry prepared by using the method disclosed by the invention is good in rheological properties and low in viscosity; and the blank prepared by using the method disclosed by the invention is uniform and compact in microstructure, and the strength of the blank is suitable for machining needs.

Description

technical field [0001] The invention belongs to the field of electronic materials and relates to a barium strontium titanate (Ba 0.6 Sr 0.4 TiO 3 , BST)-magnesium oxide (MgO)-based ceramic material in the tape casting process to form a high-quality green sheet preparation method. Background technique [0002] Barium strontium titanate (BST)-based ferroelectric materials have the advantages of high dielectric constant, low dielectric loss and high voltage adjustability, and are widely used in microwave adjustable devices such as phase shifters, filters, variable Capacitors and delay lines, etc., especially in the application of LTCC low temperature co-fired ceramics (Low Temperature Co-fired Ceramic) are current research hotspots. For the application of microwave tunable device, BST material should have moderate dielectric constant (~200), low dielectric loss (<2×10 -3 ), high permittivity bias field tunability and small permittivity temperature change rate, therefore,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/468C04B35/04C04B35/622
Inventor 季惠明王灿李晓雷高鹏周玉贵
Owner TIANJIN UNIV
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