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Method for sintering synthesis of yttrium niobate microwave dielectric ceramic by using CaF2 as fluxing agent

A technology of microwave dielectric ceramics and flux, which is applied in the direction of ceramics and inorganic insulators, and can solve the problems of preparation methods and dielectric properties that have not been reported in special research reports.

Inactive Publication Date: 2009-07-22
BEIJING JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since YNbO 4 The structure is similar to the currently commonly used calcium titanate structural ceramics, and it has [NbO 6 ] Octahedron is the layered structure of the skeleton, and it also has the special properties of rare earth elements, YNbO 4 Ceramics will also have a very unique position and value in the field of microwave dielectric ceramics, but there are no special research reports on its preparation methods and dielectric properties.

Method used

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  • Method for sintering synthesis of yttrium niobate microwave dielectric ceramic by using CaF2 as fluxing agent
  • Method for sintering synthesis of yttrium niobate microwave dielectric ceramic by using CaF2 as fluxing agent
  • Method for sintering synthesis of yttrium niobate microwave dielectric ceramic by using CaF2 as fluxing agent

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Step 1. Weigh Y with a molar ratio of 1:1 2 O 3 , Nb 2 O 5 Powder, Nb 2 O 5 The purity is 99.9%, d 50 = 8.3 microns and Y 2 O 3 The purity of 99.8%, d 50 =7.9 microns, placed in an alumina ball milling tank; add 0.5% (mass percentage) of CaF in total 2 Powder, placed in the same alumina ball mill tank.

[0027] Step 2. Weigh the agate with a diameter of 12mm according to the ratio of ball to material volume of 2:1, and place it in the alumina ball milling tank; weigh the anhydrous alcohol in the alumina ball milling tank according to the liquid to material volume ratio of 0.7:1 .

[0028] Step 3: Fix the ball milling jar on the planetary ball mill, and ball mill for 2 hours at a rotation speed of 180r / min.

[0029]Step 4. Separate the mixed slurry from the grinding balls, dry at 60°C, sieve the dried powder with 20 mesh and 100 mesh sieves, repeat the operation twice to obtain a uniformly mixed raw material;

[0030] Step 5: Weigh the uniformly mixed raw materials and place...

Embodiment 2

[0033] Same as the other conditions of the embodiment, CaF 2 When the addition amount is 0.1% (mass percentage) of the total, the heating rate is 30°C / min, the temperature is sintered to 1050°C, the holding time is 30min, and the natural cooling is used to prepare YNbO 4 Ceramic block, its bulk density is 2.6g / cm 3 , The dielectric constant is 150.

Embodiment 3

[0035] Same as the other conditions of Example 1, CaF 2 When the addition amount is 2.0% (mass percentage) of the total, the heating rate is 30°C / min, the temperature is sintered to 1350°C, the holding time is 30 minutes, and the natural cooling is used to prepare YNbO 4 Ceramic block, its bulk density is 5.3g / cm 3 ,The dielectric constant is 498.

[0036] figure 1 It can be seen that YNbO was prepared at different temperatures 4 Ceramics, in which the beneficial second phase CaNb is formed 2 O 6 .

[0037] Attached figure 2 It can be seen that as the sintering temperature increases, the bulk density of yttrium niobate ceramics with different doping amounts increases, and the maximum bulk density is 5.48g / cm 3 , Reaching the theoretical density of more than 97%.

[0038] By the attachment image 3 It can be seen that with the increase of sintering temperature, different content of CaF is added 2 YNbO 4 The room temperature dielectric constant ε of ceramics is 150-498.

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Abstract

The invention discloses a method for sintering and synthesizing yttrium niobate microwave dielectric ceramics by using CaF2 as a flux. The method comprises weighing Y2O3 and Nb2O5 powders with a molar ratio of 1:1 and CaF2 accounting for 0.1% to 2.0% of the total amount; Weigh the agate ball according to the volume ratio of the ball to the material 2:1 and the anhydrous alcohol with the volume ratio of the liquid to the material 0.7:1, and place them in a grinding jar; mill them at 180r / min, mix evenly, separate the above slurry from the grinding balls, Dry and sieve; Weigh the uniformly mixed raw materials and put them in a steel mold to press into a billet; Then put the block into a sleeve coated with boron nitride, put it in a furnace, and sinter without pressure under an argon atmosphere , with a temperature rise rate of 30°C / min, burn to 1050-1350°C, keep warm for 30min, and cool naturally to prepare a YNbO4 ceramic block. When the CaF2 doping amount is 2.0%, the dielectric constant ε of YNbO4 ceramics reaches a maximum of 498.

Description

Technical field [0001] The invention relates to a microwave dielectric functional ceramic material. Background technique [0002] Yttrium Niobate (YNbO 4 ) Ceramics are rare earth ceramics (RNbO 4 , R represents one of the rare earth elements from La to Lu including Y). It has been found to have a unique domain structure and different mechanical behaviors as well as optical and magnetic properties: Since the mid-1990s, researchers from various countries such as Jian Li from the United States And CMWayman on YNbO 4 Single crystal and ceramic polycrystalline materials have carried out in-depth research on the related mechanism and mechanical behavior. S. Maschio et al. in Europe, T. Takagi et al. in Japan, and Sheng Dih Yuh in Taiwan. 4 The phase-composite toughened structure was studied. Russian researchers passed the YNbO 4 X-ray photoelectron spectroscopy (XPS) was performed to study the spectral characteristics of the 4f electrons of rare earth ions and the exchange of atoms, p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/495C04B35/50H01B3/12
Inventor 张志力刘秋平许春
Owner BEIJING JIAOTONG UNIV