Preparation method for silicon carbide ceramic pipe

Abstract

A preparation method for a silicon carbide ceramic pipe includes preparation of plasticity pug, vacuum pug milling of the plasticity pug, extrusion molding and shape keeping of pipe blank bodies, shade drying and drying of the pipe blank bodies and pressureless sintering. The plasticity pug is formed by adding deionized water into silicon carbide powder, sintering auxiliaries, adhesive, plasticizer, dispersing agent and lubricant and ball-milling and mixing the deionized water, the silicon carbide powder, the sintering auxiliaries, the adhesive, the plasticizer, the dispersing agent and the lubricant. The silicon carbide ceramic pipe prepared in the preparation method has the advantages of being highly-compact, super-thin in walls and high in precision and is applicable to industrial heat exchangers.

Description

Technical field: [0001] The invention relates to a method for preparing a heat exchange tube used in the nuclear industry, in particular to a method for preparing a silicon carbide ceramic tube. Background technique: [0002] If the heat exchange tube of the heat exchanger in the nuclear industry leaks radioactive substances during the working process, it will cause radioactive hazards to the surrounding workers, residents and the environment. Silicon carbide ceramics have excellent high temperature resistance, corrosion resistance and radiation resistance, and can work in oxidation, corrosive atmospheres and radiation environments at high temperatures for a long time, so they are often used to make heat exchangers for nuclear industry heat exchangers. Tube. [0003] At present, although the US patent US5227105 uses boron carbide and carbon as sintering aids to prepare silicon carbide heat exchange tubes through a series of continuous production processes such as extrusion,...

AI Technical Summary

Problems solved by technology

Due to the presence of free silicon in the silicon carbide ceramic tube sintered by reaction infiltration, its resistance to strong acid media such as hydrofluoric acid or alkali is poor, and it cannot be used in the working environment of the nuclear industry.

[0005] In addition, the Chinese patent CN101581552A adopts an extrusion molding process to prepare a silicon carbide heat exchange tube. Although the density of the silicon carbide heat exchange tube reaches 95.9% and the straightness reaches 2.5 mm / m, the density is still low. The problem of large straightness tolerance

[0006] In addition, the Chinese patent CN101560104A adopts an extrusion molding process to prepare a pressureless sintered silicon carbide ceramic tube, but the silicon carbide ceramic tube does not have ultra-thin wall characteristics