High Purity Silicon Carbide Heating Element for Varioue Furnace

1.What's the Silicon Carbide(Sic) heating element?

The SiC electrothermal element is a rod-shaped non-metallic thermoelectric element which is made of high quality green SiC as the main raw material through processing, high temperature silicification and recrystallization. Compared with metallic electric heating elements, this element has the characteristics of high operating temperature, oxidation resistance, corrosion resistance, long service life, small deformation, convenient installation and maintenance.

2.Applications of silicon carbide heating element: 

It can be widely used in such applications as sintering and heating elements of ceramics, magnet, glass, metallurgy, refractory, etc.

3.Advantages of silicon carbide heating element: 

Our silicon carbide electrothermal elements adopt a new hot-cold end production process, with excellent hot-cold end resistance ratio, energy saving, long life, while avoiding the damage to the furnace caused by the high temperature of cold end.

1.) ED(rod)type elements

2.)  DB(dumbbell)type elements

3)  U type elements

4) W(three phase)type elements

5) SC(single spiral)type element

6) SC(double spiral)type elements

7) UX(slot)type elements

 Physical properties

Chemistry Property

1.Antioxidation Property of Elements
The element start to being oxidized when heat to 800°C in air, and a SiO2 protect film will be generated in surface of hot zone when temperature get to 1000-1300°C ; cristobalite will be crystallized at 1300°C; the protect film get to a certain thickness when the temperature get go 1500°C which make the oxidation speed being very slowly to stable. if continue to heat to over 1627°C ,the protect film will be damaged and oxidation speed will be more rapid evidently and make the element damaged earlier.
Thought the element will be oxidized very slowly in course of application, it also will make the resistance increased following long time application, this phenonenon calls ageing , in order to lower the ageing speed, we use special technology to spread a protect film on the surface of hot zone in the course of production, which enhance the antioxidant property of element evidently and lengthen the service life.

2.The effects of alkali and alkaline metal oxide to elements.
The alkali and alkaline metal oxide will react with SiC at about 1300°C and generate silicate, which calls alkali-chemical corrosion, and can influence the glowing of element. 

3.The effects to elements from melting metal
Some metals ,such as cobalt, nickel, chrome and so on, can corrade the element in high temperature melting state and affect the service life of element.


Electric Property

SIC heating elements has rather large specific resistance , when it is heated in air and the surface temperature of the hot zone reaches 1050ºC, it's resistance rate is 600-1400 mm2/mm (square millimetre , its resistance value changes as the temperature rises. From room-temperature to 800ºC is negative value , over 800ºC is positive value nature curve.
 

Notice for using of silicon carbide heating element

1. Heater should be protected against damp during storing or installing to ensure the performance of the heater. 
2. In order to be sure of well-distributed lod of each and groups, heater should be divided before assembling. The tolerance of the resistance of each one cannot exceed by 10% each other. 
3. Heater is hard and brittle, please be careful when assembling and maintaining so as to avoid damage. 
4. When operating the electric furnace at the beginning, the voltage should be increased slowly and cannot be fully loaded at once. Otherwise the larger current will be resulted in the damage of heater. 
5. When heater is damaged and need to be changed, the resistance of new one should follow the increasing resistance. If many are damaged or resistance increased too much, heater should be changed.