A method for densification of SIC materials based on reactive sintering of loose defects

A reaction and defect technology, which is applied in the dense field of reactive sintered SiC materials based on loose defects, can solve the problems of reduced strength, fragility, waste, etc., and achieve the effects of reducing manufacturing costs, easy operation and realization, and improving utilization rate

Active Publication Date: 2021-02-12
CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For reaction sintered SiC structural parts, the presence of porosity will greatly reduce its strength, and it will be easily broken during use, resulting in unqualified materials; especially for SiC optical materials - mirrors, porosity on the mirror surface will directly lead to reflection The mirror surface cannot be optically processed, making the entire mirror unusable
However, the manufacture of reaction sintered SiC mirrors is difficult and costly. Directly treating the reaction sintered SiC mirrors with loose structures as waste products will cause great waste; and the production cycle of reaction sintered SiC mirrors is long, and the reaction sintered SiC mirrors with loose structures are directly discarded. Sintering SiC mirrors will lead to a significant extension of the manufacturing cycle of optoelectronic devices using SiC mirrors as one of their main components

Method used

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Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment 1

[0030] A dense method based on loose defect reactive sintering of SiC materials, the method comprising:

[0031] Take the reaction sintering reaction sintering SiC material with a diameter of 200mm, a thickness of 11mm, and a margin of 1mm in the thickness direction; the theoretical Si content is 30%, and the SiC content is 70%; the reaction sintered SiC with several loose and loose defects inside is found by non-destructive testing. The material is wrapped with 20mm thick carbon fiber felt, placed in a vacuum sintering furnace, evacuated to below 10pa, heated to 1800°C at a heating rate of 50°C / h, and kept for 10h, so that silicon escapes from the loose defect reaction sintered SiC material , react with the carbonaceous material on the outer surface of the reaction sintered SiC material that wraps loose defects, remove silicon, and cool down to room temperature at a cooling rate of 50°C / h to obtain preform a (take out the material of preform a and weigh; preform a Only when t...

specific Embodiment 2

[0035] Put the reaction sintered SiC material with loose defects in vacuum, raise the temperature to 1600 °C at a heating rate of 40 °C / h, and keep it for 12 hours, so that silicon escapes from the reaction sintered SiC material with loose defects, and sinters with the reaction sintered SiC material that wraps loose defects The carbonaceous material on the outer surface of the SiC material reacts to remove silicon, wherein the carbonaceous material is multi-layer carbon fiber cloth, and the temperature is lowered to room temperature at a cooling rate of 40°C / h to obtain the preform a.

[0036] Grind the surface of preform a to remove 0.2mm from the surface of preform a, place a sufficient amount of silicon in a vacuum environment, contact the polished surface with silicon, raise the temperature to 1600°C at a heating rate of 60°C / h, and keep it warm for 0.8h , so that the silicon is melted and infiltrated into the preform a, and a dense reaction sintered SiC material is obtaine...

specific Embodiment 3

[0039] Place the reaction sintered SiC material with loose defects in vacuum, raise the temperature to 2000 °C at a heating rate of 60 °C / h, and keep it for 8 hours, so that silicon escapes from the reaction sintered SiC material with loose defects, and sinters with the reaction sintered SiC material that wraps loose defects The carbonaceous material on the outer surface of the SiC material reacts to remove silicon, wherein the carbonaceous material is porous carbon fiber felt or multi-layer carbon fiber cloth, and the temperature is lowered to room temperature at a cooling rate of 60°C / h to obtain the preform a.

[0040] Grind the surface of preform a to remove 0.2mm on the surface of preform a, place a sufficient amount of silicon in a vacuum environment, contact the polished surface with silicon, raise the temperature to 1450°C at a heating rate of 40°C / h, and keep it warm for 1.5h , so that the silicon is melted and infiltrated into the preform a, and a dense reaction sinte...

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Abstract

The invention discloses a method for densifying SiC materials based on reaction sintering of loose defects. Escape from the SiC material and react with the carbonaceous material on the outer surface of the reaction sintered SiC material that wraps loose defects, cool down to obtain a preform a; treat the surface of the preform a, place a sufficient amount of silicon in a vacuum environment, and heat up to Above the melting point of silicon, keep it warm for a period of time, so that the silicon melts and infiltrates into the prefabricated body a, and a dense reaction sintered SiC material is obtained, which avoids the waste of the reaction sintered SiC material with loose defects, improves its utilization rate, improves the authenticity rate of the product, and greatly The manufacturing cost is reduced, and the method is simple, has few steps, and is easy to operate and realize.

Description

technical field [0001] The invention relates to the field of reaction sintering of SiC materials, in particular to a method for densifying SiC materials based on reaction sintering of loose defects. Background technique [0002] Reaction sintered silicon carbide has the advantages of simple process, short sintering time, low sintering temperature and cost, net size sintering, and easy preparation of large and complex shape products. Therefore, it has become the first structural ceramic to achieve large-scale industrial applications and has broad application prospects. The preparation process is to make a blank with pores from silicon carbide particles and carbon powder, which is in contact with liquid silicon at high temperature (above the melting point of silicon), and the liquid silicon penetrates into the green body through the pores of the green body, and the carbon in the green body and The infiltrated silicon reacts to form silicon carbide, and the remaining liquid fre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/565C04B35/622
CPCC04B35/565C04B35/622C04B2235/428C04B2235/6562C04B2235/6565C04B2235/6567
Inventor 董斌超张舸曹琪包建勋郭聪慧崔聪聪
Owner CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI
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