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Silicon carbide base multiphase composite ceramic and its preparation method

A technology of composite ceramics and silicon carbide, applied in the field of preparation of silicon carbide ceramics, can solve the problems of high cost, affecting the performance of silicon carbide, poor reinforcement effect, etc., achieve high performance and overcome the effect of uneven distribution of additives

Active Publication Date: 2008-01-23
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 1) Whether it is whisker reinforcement, fiber reinforcement, or particle reinforcement, the biggest difficulty in the process is that due to the difference in structure and specific gravity, it is difficult to achieve uniform dispersion between the reinforcement element and the matrix, so that the reinforcement The effect is not good, and even affects the performance of silicon carbide itself; therefore, it is particularly important to take measures to homogenize the composite components;
[0006] 2) The preparation process of whisker reinforcement and fiber reinforcement is complicated, the cost is high, and it is difficult to realize industrial production; although the particle reinforcement process is relatively easy to implement, the introduced particles have a great impact on the performance of silicon carbide composite materials, such as resistance Oxidation, corrosion resistance and high temperature strength are unfavorable; self-reinforcement or in-situ reinforcement technology must be realized by advanced preparation technology; therefore, it is necessary to adopt simple and low-cost reinforcement measures in actual production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Embodiment 1. A silicon carbide-based multiphase composite ceramic, the composition of which is composed of 90% SiC with a purity of more than 99.5% and 10% YAG by weight.

[0025] According to the above weight ratio, the specific preparation method is as follows:

[0026] 1) Use HF and HNO to powder SiC with an average particle size of 0.78 microns 3 The mixed acid solution is used for pickling, so that the purity of SiC after pickling can reach more than 99.5%;

[0027]2), using a wet chemical method, prepare a colloid with a weight ratio of YAG and deionized water of 15:85, and then add the above-mentioned SiC powder and PVA as a binder to the colloid, stir, dry, and dry at 920-950 Heat treatment at ℃ for 4-6 hours to make multi-phase composite powder, the amount of PVA is 3% of the total weight of SiC powder; the precursors of YAG are all chemical reagents, and the purity is greater than 99.9%;

[0028] 3) The above-mentioned multi-phase composite powder is pre-pr...

Embodiment 2

[0030] Embodiment 2, a silicon carbide-based multi-phase composite ceramics, the composition of the ceramics in weight percentage is: SiC82% with a purity of more than 99.5%, AlN10% and YAG8%.

[0031] According to the above weight ratio, the specific preparation method is as follows:

[0032] 1) Use HF and HNO to powder SiC with an average particle size of 0.78 microns 3 The mixed acid solution is used for pickling, so that the purity of SiC after pickling can reach more than 99.5%;

[0033] 2), adding powdery AlN to the above SiC, and mixing uniformly to make a mixed powder;

[0034] 3), adopt wet chemical method, prepare the colloid that YAG and deionized water weight ratio are 15:85, then add above-mentioned mixed powder and PVA as binder in this colloid, carry out stirring, drying, at 920~950 Heat treatment at ℃ for 4 to 6 hours to make a multi-phase composite powder, the amount of PVA is 4% of the total weight of the mixed powder; the precursors of YAG are all chemical...

Embodiment 3

[0037] Embodiment 3, a kind of silicon carbide-based multiphase composite ceramics, the weight percentage of this ceramics is composed of: SiC72% with a purity of more than 99.5%, Si 3 N 4 18% and YAG-Al 2 o 3 10%.

[0038] According to the above weight ratio, the specific preparation method is as follows:

[0039] 1) Use HF and HNO to powder SiC with an average particle size of 0.78 microns 3 The mixed acid solution is used for pickling, so that the purity of SiC after pickling can reach more than 99.5%;

[0040] 2) Add powdered Si to the above SiC 3 N 4 , mixed evenly to make a mixed powder;

[0041] 3), using wet chemical method to prepare YAG-Al 2 o 3 A colloid with a weight ratio of 15:85 to deionized water, and then add the above mixed powder and PVA as a binder into the colloid, stir, dry, and heat treat at 920-950°C for 4-6 hours to make a poly Phase composite powder, the amount of PVA is 5% of the total weight of the mixed powder; the precursors of YAG are a...

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Abstract

The present invention discloses a silicon carbide base multiphase composite ceramic. Its composition includes (by wt%) 72-90% of silicon carbide whose purity is up to 99.5%, 0-18% of aluminium nitride or silicon nitride and 8-10% of yttrium-aluminium-garnet or yttrium-aluminium-garnet / alumina. Said invention also provides its preparation method and concrete steps.

Description

technical field [0001] The invention relates to a method for preparing silicon carbide ceramics, in particular to a method for preparing silicon carbide-based multiphase composite ceramics. Background technique [0002] As a high-temperature structural material, silicon carbide ceramics have incomparable properties of other materials, such as high-temperature thermal stability, wear resistance, acid and alkali corrosion resistance, good thermal shock resistance, low expansion coefficient, high thermal conductivity, and creep resistance. And good antioxidant properties and so on. Silicon carbide ceramic materials have been widely used in machinery, electronics, petrochemical, metallurgy and other industrial fields as well as national defense industry. As a new generation of mechanical sealing materials, silicon carbide has been recognized internationally as the fourth basic material since metal, alumina, and hard alloy. Although silicon carbide ceramics have many properties...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/565C04B35/622
Inventor 郭兴忠高黎华傅培鑫李祥云王建武
Owner ZHEJIANG UNIV