Method for preparing SiC heating element having long service life

Abstract

The invention discloses a method for preparing a SiC (silicon carbide) heating element having long service life. The method comprises the following steps: proportioning the following components by mass percentage: 75% to 90% of SiC, 1% to 5% of Al2O3, 1% to 5% of ZrO2, 1% to 3% SiO2, 4% to 10% of Si and 1% to 5% of C; preparing the components into a hollow pipe by using the extrusion molding process; drying at 80 to 300 DEG C; sintering at 1,450 to 1,650 DEG C in the presence of protective nitrogen, cutting into a heating part, and testing the resistance of the heating part for later use; proportioning the following components by mass percentage: 70% to 90% of SiC, 1% to 5% of Ni, 1% to 5% of Mo, 1% to 5% of Ti, 1% to 5% of TiC, 5% to 10% of Si and 1% to 5% of C; sintering the components by using the same process of forming and sintering as the heating part, cutting into a cold-side part, testing the resistance of the cold-side part for later use; and welding the cold-side parts at two ends of the heating part at the local-welding temperature of 1,500 to 1,600 DEG C, to complete the preparation of the entire heating element.

Description

technical field [0001] The invention relates to a method for preparing a heating element, in particular to a method for preparing a SiC heating element. Background technique [0002] SiC (silicon carbide) heating elements, also known as silicon carbide rods, usually consist of two parts: a heating part and a cold end part ( figure 1 ). The heating part is generally sintered by SiC recrystallization, and the sintering temperature is usually around 2200°C. The porosity is 15-20%, and the strength is 75-100Mpa; the resistivity is relatively large, generally 15-20 times that of the cold end. At present, the cold end material is mainly processed by reaction sintering and infiltration. The porosity is less than 1%, dense, the strength is as high as 250MPa, and the resistivity is small. The optimum operating temperature of silicon carbide rods is generally 800°C to 1350°C. The heating part is at a high temperature, and the surface of SiC reacts with oxygen to produce an oxidatio...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem of short service life of traditional silicon carbon rods, the present invention provides a preparation method of long-life SiC heating elements

Images