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Method for preparing fine-crystalline and high-strength magnesia alumina spinel transparent ceramic

A technology for magnesia-alumina spinel and transparent ceramics, which is applied in the preparation field of enhancing the mechanical strength of magnesia-alumina spinel transparent ceramics, which can solve the problem of grain growth, grain boundary micro-cracks, and reduce the strength of magnesia-alumina spinel transparent ceramics And other issues

Active Publication Date: 2017-12-15
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Using LiF as a sintering aid, while promoting the densification rate, the grains are prone to abnormal growth; at the same time, the LiAlO produced by the residual lithium salt 2 Such products can easily lead to grain boundary microcracks, thereby reducing the strength of magnesium aluminum spinel transparent ceramics

Method used

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  • Method for preparing fine-crystalline and high-strength magnesia alumina spinel transparent ceramic
  • Method for preparing fine-crystalline and high-strength magnesia alumina spinel transparent ceramic
  • Method for preparing fine-crystalline and high-strength magnesia alumina spinel transparent ceramic

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[0029] In the present invention, the preparation method of the fine-grained, high-strength magnesia-alumina spinel transparent ceramics includes the steps of powder treatment, molding, sintering and annealing. The preparation method of the fine-grained, high-strength magnesium-aluminum spinel transparent ceramic provided by the present invention is exemplarily described below.

[0030] The powder treatment is to mix magnesium aluminum spinel powder with a certain amount of rare earth metal oxide (RE 2 o 3) or / and the precursor of the rare earth metal oxide by ball milling (wherein, the rotation speed may be 300 rpm, and the time may be 4-12 hours), and then the powder is sieved. The chemical formula of the commercial magnesium-aluminum spinel raw material powder can be expressed as MgO·nAl 2 o 3 , n=1˜1.5, preferably 1˜1.1. The particle size of the magnesium aluminum spinel powder can be 50-200nm, and the purity can be ≥99.9%. Adopted RE 2 o 3 Containing at least one of...

Embodiment 1

[0036] Powder treatment: Weigh 80g of magnesia-aluminum spinel powder, use ethanol as the dispersion medium, and high-purity alumina balls as the ball milling medium. After ball milling at a speed of 300 rpm for 6 hours, place the slurry in an oven at 60°C Dry in medium for 12 hours, then pass through 80 mesh sieve;

[0037] Molding: The calcined powder is formed by dry pressing (20MPa, holding pressure for 20 seconds) combined with cold isostatic pressing (200MPa, holding pressure for 5 minutes) to obtain magnesium aluminum spinel ceramic green body;

[0038] Sintering: Put the formed green body in a muffle furnace for 8 hours at 800°C and then pre-sinter it in a vacuum furnace at 1525°C for 6 hours. Static pressure sintering, holding time is 4 hours;

[0039] Annealing heat treatment: heat the sample sintered by hot isostatic pressing in a muffle furnace at 1250° C. for 10 hours.

[0040] figure 1 The magnesia-aluminum spinel transparent ceramic photo obtained by the meth...

Embodiment 2

[0043] The preparation process is similar to that of Example 1, the difference is that when weighing the powder, in addition to weighing 80g of magnesium aluminum spinel powder, it is also necessary to weigh 0.008g (100ppm) Y 2 o 3 , The process of powder treatment, molding and bisque firing is the same as in Example 1. The bisque-fired sample was pre-fired in a vacuum furnace at a sintering temperature of 1550°C for 6 hours, and then the pre-fired sample was sintered by hot isostatic pressing at a sintering temperature of 1600°C and a pressure of 196 MPa for 4 hours.

[0044] image 3 For the doping 100ppm Y that embodiment 2 makes 2 o 3 Photograph of a magnesia-alumina spinel transparent ceramic sample after double-sided polishing, courtesy of image 3 It can be seen that the prepared doped Y 2 o 3 The sample has good optical transparency in the visible light range, and the optical uniformity is very good;

[0045] Figure 4 For the surface and cross-section SEM phot...

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Abstract

The invention relates to a method for preparing a fine-crystalline and high-strength magnesia alumina spinel transparent ceramic. The method comprises the following steps of (1), uniformly mixing magnesia alumina spinel powder and a sintering additive, so as to obtain raw material powder, wherein the sintering additive is RE2O3 and / or a precursor which can be decomposed to obtain the RE2O3, wherein RE is selected from at least one of rare earth elements; (2), subjecting the obtained raw material powder to compression molding, so as to obtain a ceramic biscuit; (3), biscuiting the obtained ceramic biscuit for 2 to 10 hours at 600 to 1,100 DEG C, then carrying out pre-sintering treatment for 4 to 8 hours at 1,350 to 1,650 DEG C, and finally carrying out hot isostatic pressing sintering for 1 to 6 hours under 120 to 200MPa and at 1,450 to 1,900 DEG C, so as to obtain the magnesia alumina spinel transparent ceramic.

Description

technical field [0001] The invention specifically relates to a preparation method for enhancing the mechanical strength of magnesium-aluminum spinel transparent ceramics, and belongs to the technical field of transparent ceramic materials. Background technique [0002] Magnesium aluminum spinel transparent ceramic material not only has the advantages of high strength, high hardness, corrosion resistance, wear resistance, etc., but also has the advantages of Al 2 o 3 The optical performance of single crystal is similar, and it has high optical transmittance in the ultraviolet to mid-infrared band. As a new type of optical material, it is widely used in various fields such as national defense and civil industry. [0003] In the early 1960s, GE Company of the United States synthesized magnesium-aluminum spinel powder by solid-state reaction method, using Li 2 O and SiO 2 As a sintering aid, magnesium aluminum spinel transparent ceramics were prepared for the first time by va...

Claims

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Application Information

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IPC IPC(8): C04B35/443C04B35/622C04B35/64
CPCC04B35/443C04B35/622C04B35/64C04B2235/96C04B2235/9653
Inventor 韩丹刘鹏章健王士维李桂
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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