Vertical Bridgman preparation method for large-size aluminum oxide-yttrium aluminum garnet eutectic ceramic

A technology of vertical Bridgman and yttrium aluminum garnet, which is applied in the field of vertical Bridgman preparation method of large-scale alumina-yttrium aluminum garnet eutectic, which can solve the problems of small diameter of ceramic rod or plate thickness, and achieve normal temperature And the effect of outstanding high-temperature mechanical properties, easy processing, and strong thermal stability

Inactive Publication Date: 2015-08-19
HARBIN INST OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The micro-drawing method is currently only suitable for the preparation of high-performance submicron phase structure ceramic fibers due to the volume limitation of the high-temperature directional solidification furnace; for the laser suspension zone melting method, due to the high absorption coefficient of the ceramic melt for laser radiation and the inherent low heat of the ceramic conductivity, resulting in a small diameter or plate thickness of the prepared ceramic rod (only a few millimeters)

Method used

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  • Vertical Bridgman preparation method for large-size aluminum oxide-yttrium aluminum garnet eutectic ceramic

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specific Embodiment approach 1

[0017] Specific embodiment one: the vertical Bridgman method (Bridgman) preparation method of a kind of large-scale alumina-yttrium aluminum garnet eutectic ceramics of the present embodiment, it comprises the following steps:

[0018] 1. Weigh 81.5mol% Al according to the mole percentage 2 o 3 and 18.5 mol% of Y 2 o 3 ;

[0019] 2. The Al taken in step 1 2 o 3 and Y 2 o 3 After being uniformly mixed by anhydrous ethanol wet ball milling, drying to remove anhydrous ethanol, and then calcining at 1273K for 15 hours, then putting it into a cylindrical plastic mold, and pressing it into a rod with a hydraulic press under the condition of 150MPa, and then The bar is sintered for 3 hours under the condition of air atmosphere and 1973K to obtain the bar body;

[0020] 3. Place the rod raw material obtained in step 2 in a molybdenum cylindrical crucible with YAG seed crystals after washing with absolute ethanol, put the molybdenum cylindrical crucible into the descending furn...

specific Embodiment approach 2

[0022] Specific embodiment two: the difference between this embodiment and specific embodiment one is: in the step 3, the relationship between the amount of bar raw material added and the inner diameter and length of the molybdenum cylindrical crucible is calculated according to the following formula: M=π*( d / 2) 2 *l*ρ; where M is the amount of raw material added, d is the inner diameter of the upper port of the molybdenum cylindrical crucible, l is the length of the molybdenum cylindrical crucible, and ρ is the density of the eutectic. Others are the same as in the first embodiment.

specific Embodiment approach 3

[0023] Embodiment 3: The difference between this embodiment and Embodiment 1 is that the inner diameter of the cylindrical crucible made of molybdenum does not exceed the space in the thermal field of the descending furnace. Others are the same as in the first embodiment.

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Abstract

The invention relates to a vertical Bridgman preparation method for large-size aluminum oxide-yttrium aluminum garnet eutectic ceramic. The process of the method is characterized in that aluminum oxide-yttrium aluminum garnet eutectic ceramic grows at an argon atmosphere through a VB method. The specific growth process comprises four major processes, including raw material preparation, process before heating, eutectic growth, and cooling and annealing. By combining the advantages of a directed crystallization method and a vertical zone-melting method for crystal growth, the prepared aluminum oxide-yttrium aluminum garnet eutectic ceramic is enabled to have the advantages of large size, few defect, high hardness, outstanding mechanical property at normal temperature and high temperature, strong thermal stability, easiness in processing and the like.

Description

technical field [0001] The invention relates to a growth method for preparing eutectic ceramics, in particular to a vertical Bridgman preparation method for large-scale alumina-yttrium aluminum garnet eutectics. Background technique [0002] Alumina-yttrium aluminum garnet eutectic ceramics have excellent oxidation resistance, corrosion resistance and mechanical properties at high temperatures, which fully meet people's stringent requirements for high-temperature structural materials in the advanced aerospace field. Compared with traditional single crystal superalloy (density 8.0g / cm 3 ) compared to the low density (4.1g / cm 3 ), it is estimated that the thermal efficiency can be increased by up to 9% when used in gas turbines, which has great engineering application prospects and potential economic value. Therefore, in recent years, this material has attracted widespread attention from all over the world, and it is expected to become the first choice for ultra-high tempera...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B11/00C30B29/20C30B29/28
Inventor 刘洋张明福赵业权聂颖
Owner HARBIN INST OF TECH
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