Method for manufacturing cold end part of silicon carbide rod by cubic silicon carbide

Abstract

The invention provides a method for manufacturing a cold end part of a silicon carbide rod by cubic silicon carbide. In the method, an adhesive is added to the cubic silicon carbide to carry out extrusion forming, and then biscuit firing treatment is carried out so as to form a biscuit fired product; the biscuit fired product is buried by a burying material, then high-temperature siliconizing and silicifying are carried out under the temperature of 1,700 to 2,000 DEG C, protective gas is filled for protection at the same time, and the siliconizing and silicifying treatment of the biscuit fired product is finished after 1.5 to 2.5 hours so as to obtain the finished cold end part of the silicon carbide rod. The method for manufacturing the cold end part of the silicon carbide rod by the cubic silicon carbide can obviously lower the resistance rate of the cold end part, and has the characteristics of high finished product rate, low production cost, short production time and high economical as well as social benefits; moreover, the processing controllability is also improved.

Description

technical field [0001] The invention relates to a method for manufacturing a cold end of a silicon carbide rod, in particular to a method for manufacturing a cold end of a silicon carbide rod by using cubic silicon carbide. Background technique [0002] Silicon carbon rod (SIC electric heating element) is made of high-purity dense green SIC recrystallized at high temperature. As an electric heating element, it saves a lot, replaces and is superior to some metal electric heating materials; it has strong acid corrosion resistance , Anti-oxidation, anti-thermal shock and anti-bending ability; it can be used in dry air without a protective atmosphere, and the normal working temperature ranges from room temperature to as high as 1500 ° C and has a long service life. Silicon carbide rods are non-polluting during use, and are also excellent substitutes for traditional coal-fired and oil-fired industrial kilns, and are widely used in metallurgy, electronics, chemicals, ceramics, gla...

AI Technical Summary

Problems solved by technology

[0004] However, the current old processes have some defects: the production process is long, and it takes about three weeks from molding to high-temperature firing; the controllability of technical means is poor, especially the resistance furnace silicidation process, the resistance furnace used is the same as silicon carbide smelting The furnace is horizontal and works intermittently. The hearth is paved with refractory bricks, and the furnace core heating element is pressed with graphite electrode powder.

The technology of this kind of resistance furnace is backward, and the temperature cannot be measured. The temperature in the furnace can only be estimated by calculating the power consumption. It is buried in silicified material and protective material and fired, and the influencing factors are complex and numerous. The production of the furnace core body, the preparation of silicified material and protective material, and the placement of plain products all rely on manual experience. In addition, the temperature difference between various parts in the furnace is extremely Large, every 1cm difference between the inside and the outside has a temperature difference of at least 50°C, so the process controllability is extremely poor, resulting in a low product qualification rate and uneven quality.

In addition, it is usually required that the resistivity of the cold end part and the heating part cannot be lower than 10:1, while the old process production can only reach 7-8:1 under normal circumstances, and the pass rate is about 50%.

In addition, the use of old-fashioned resistance furnaces is labor-intensive, the production environment is harsh, and polluting gases are produced.

[0005] In short, the old technology and equipment operation level have low guarantee coefficient and low controllability, resulting in low product qualification rate, long production cycle and high production cost. The most important thing is that the resistance coefficient of the cold end produced is still high. For resistance heating elements, the smaller the resistance of the cold end, the better, the smaller the power saving, and the less damage to the furnace body