A kind of preparation method of silicon carbide ceramic tube

Abstract

The invention belongs to the technical field of silicon carbide ceramic material preparation, in particular to a method for preparing a silicon carbide ceramic tube with high compactness and high processing precision. The silicon carbide ceramic pipe product has uniform structure, high compactness and high coaxiality. The steps of the preparation method include: (1) powder configuration, (2) device adjustment, (3) powder filling, (4) cold isostatic pressing, (5) core-pulling and trimming finishing, and (6) high-temperature sintering. The invention solves the processing deformation problem of the silicon carbide ceramic tube, and the manufactured silicon carbide ceramic tube is suitable for high-precision environments such as the nuclear industry.

Description

technical field [0001] The invention relates to the technical field of engineering ceramic materials, in particular to a method for preparing a silicon carbide ceramic tube. Background technique [0002] Silicon carbide ceramics have the characteristics of high thermal conductivity, small expansion coefficient, small bulk density, high hardness, good wear resistance, high temperature resistance, good chemical stability, and high strength, so they are suitable for high temperature, corrosion, and oxidation environments. During the working process, the heat exchange tubes of nuclear industry heat exchangers have extremely high requirements on the high temperature resistance, corrosion resistance and corrosion resistance of the pipe fittings. Because of its excellent characteristics, silicon carbide can work at high temperatures for a long time in oxidation, Corrosive atmosphere and radiation environment, so it is often used to make heat exchange tubes for nuclear industry heat...

AI Technical Summary

Problems solved by technology

This method is more traditional. The advantage is that it can mold products with complex shapes. The disadvantage is that the cost of the mold is high, and it is easy to crack after drying, and the efficiency is low and the cost is high.

[0007] (3) Casting reaction sintering: heating the mixed green body of silicon carbide and carbon, the carbon in the green body reacts with gaseous silicon or liquid silicon to form a porous and pure silicon carbide or a kind of pore filled with excess silicon Silicon carbide, but the control of the reaction sintering process is relatively difficult, and there is a phenomenon of impervious sintering of dead skin. It is very important to correctly select the ratio of silicon carbide and carbon in the mixture, and the form and nature of carbon are also key factors affecting the firing through , still needs further improvement

Due to the same cross-sectional shape, products with the same shape and any length can be molded, but the molding density is low, and it is easy to leave large pores

[0009] The two processing methods of casting reaction sintering and extrusion molding sintering will cause uncontrollable deformation during the sintering process due to the uneven material distribution of the green body, and the coaxiality accuracy of the final silicon carbide ceramic tube product is not high.

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