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Magnesium niobate series crystals and preparation method thereof

A technology of magnesium tantalate and crystals, which is applied in the field of microwave dielectric materials, magnesium tantalate series crystals and their preparation, can solve the problems of poor quality and performance of magnesium tantalate crystals, achieve transparent macroscopic defects, and solve the problems of easy cracking, Effects without macro defects

Active Publication Date: 2018-06-26
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the above-mentioned technical problems in the prior art, the present invention provides magnesium tantalate series crystals and a preparation method thereof. The magnesium tantalate series crystals and the preparation method thereof will solve the problems of preparing magnesium tantalate crystals in the prior art. Technical issues with poor quality and performance

Method used

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  • Magnesium niobate series crystals and preparation method thereof
  • Magnesium niobate series crystals and preparation method thereof
  • Magnesium niobate series crystals and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1 micro pull-down method grows Mg 4 Ta 2 o 9 the crystal

[0042] (1) Synthesis of high-purity Mg by solid phase reaction 4 Ta 2 o 9 Powder

[0043] 1) 5.2Mg(OH) 2 :1Ta 2 o 5 Synthetic pure phase Mg 4 Ta 2 o 9 Powder

[0044] According to the molar ratio of 5.2:1, the Mg(OH) with a purity of 99.999% and 99.99% was weighed 2 and Ta 2 o 5 A total of 5g of raw materials were put into a mortar, ground and mixed, sieved with 220 mesh, and put into a ZrO 2 In the ball mill jar, mill on a ball mill for 1 hour. Under the action of 350MPa pressure, a cylindrical sheet with a size of Φ13mm×5mm was prepared, put into a muffle furnace for pre-firing at 1300°C for 16h, and the heating and cooling rate was 100°C / h. The phase-pure powder XRD ( figure 2 (a)) for characterization.

[0045] 2) 5.6Mg(OH) 2 :1Ta 2 o 5 Synthetic pure phase Mg 4 Ta 2 o 9 Powder

[0046] The ratio of raw materials was increased to 5.6:1, and the pre-fired temperature was ...

Embodiment 2

[0057] Embodiment 2 grows Mg by micro pull-down method 3 Ta 2 o 8 the crystal

[0058] The high-purity powder raw material Mg(OH) 2 (99.999%) and Ta 2 o 5 (99.99%) according to the molar ratio of 4:1 ingredients, a total of 5g into the mortar to grind and mix, 220 mesh sieve, put it into the ZrO 2 In the ball mill tank, mill on the ball mill for 1 hour, grind the milled material in the mortar again, sieve through 220 mesh, press 350MPa into a cylindrical piece with a size of Φ13mm×5mm, and put it into a high-temperature muffle furnace , set the pre-burning temperature to 1300°C, hold time to 16h, and heat up and down at a rate of 100°C / h. The phase purity of the obtained ceramic cylinder is characterized by powder XRD, and its spectrum features are as follows: Figure 7 (a). No Mg was found 3 Ta 2 o 8 Phase, is 0.62Mg 4 Ta 2 o 9 +0.38MgTa 2 o 6 Mixed phase, according to phase diagram analysis, its components are roughly in the Mg 3 Ta 2 o 8 near the componen...

Embodiment 3

[0062] Embodiment 3 grows MgTa by micro pull-down method 2 o 6 the crystal

[0063] The raw material Mg(OH) 2 (Noah chemical, 99.999%) and Ta 2 o 5 (Aldrich, 99.99%) weighed at a molar ratio of 1.15:1, mixed in a 5g mortar, sieved at 220 mesh, ball milled for 1h, and under 350MPa, a cylindrical piece of Φ13mm×5mm was prepared, and put into a muffle furnace for 1400 Pre-burn at ℃ for 8 hours, and heat up and down at 100℃ / h. Powder XRD, such as Figure 10 (a) shows that the obtained ceramic sheet is pure phase MgTa 2 o 6 . The synthesized pure phase MgTa 2 o 6 Powder and Mg(OH) 2 The powder is ball-milled and mixed at a molar ratio of 100:1, and a total of 5 g is dry-pressed into a column with a diameter of 13 mm. figure 1 shown in the Ir crucible, with Y 3 al 5 o 12 (referred to as YAG) single crystal rod as seed crystal, the upper end of the seed crystal is cut flat and polished, and kept clean and dry, fixed in the hollow Al 2 o 3 on the seed rod. Adjust var...

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Abstract

The invention discloses magnesium niobate series crystals, namely a MgO-Ta2O5 pseudo binary system. The magnesium niobate series crystals are Mg4Ta2O9, Mg3Ta2O8 and MgTa2O6, respectively. A method forpreparing the magnesium niobate series crystals is also provided. High-purity MgTa2O6 and Mg4Ta2O9 powders are synthesized by solid phase reaction using excess MgO or Mg(OH)2 component compensation,and the centimeter-scale rod-shaped MgTa2O6 and Mg4Ta2O9 single crystal is grown by a micro-downdraw method. Using Mg4Ta2O9 and MgTa2O6 as melting starting materials, a centimeter-scale rod-shaped Mg3Ta2O8 single crystal is grown on a MgTa2O6 ceramic seed rod by a spontaneous nucleation technique. According to the magnesium niobate series crystals, the micro-downdraw method is adopted, and the high temperature gradient near a growth interface is effectively utilized, to achieve rapid and high uniform crystallization; and a post-heater is effectively utilized to solve the cracking problem caused by excessive thermal stress.

Description

technical field [0001] The invention belongs to the field of chemical industry, and relates to a microwave dielectric material, specifically magnesium tantalate series crystals and a preparation method thereof. Background technique [0002] With the rapid development of microwave communication, modern mobile phones and electronic communication, microwave dielectric materials, which play an important role in communication systems, have attracted great attention from scientific researchers and technology industry manufacturers. Mg 4 Ta 2 o 9 , Mg 3 Ta 2 o 8 , MgTa 2 o 6 And its doped materials, which have excellent microwave dielectric properties and luminescent properties, have been widely studied in the form of ceramics and powders, respectively. In order to explore the MgO-Ta in depth 2 o 5 The intrinsic properties such as microwave dielectric and optics of system materials and their changes with composition, structure and crystal orientation are imminent for the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/30C30B15/08
CPCC30B15/08C30B29/30
Inventor 马云峰徐家跃蒋毅坚
Owner SHANGHAI INST OF TECH
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