ED Type Silicon Carbide Rod

The forming method determines the formula of the forming blank and the preparation method of the blank. The widely used method in China is extrusion molding, in addition to vibration molding and isostatic pressing molding. The blending of formed blanks should be reasonable to meet the requirements of the production process. If the mixing method is improper or the process control is not strict, it will not only reduce production efficiency, but also affect product quality. The formed billet should meet the following requirements:

(1) The components in the billet should be thoroughly mixed evenly, and the particle size distribution should reach the maximum possible bulk density.

(2) The amount of binder used in the defective material should be appropriate. Large dosage, easy deformation of the rod body, high porosity of the rod body, affecting the product life; Small dosage, difficult molding, or causing layer burning or rod breakage.

(3) The billet should not contain water and try to minimize bubbles. If there is water, the surface of the rod may bubble or even fail to form during molding.

Selection of binders. Most domestic silicon carbide rod manufacturers use asphalt as a binder. Because: firstly, asphalt contains a large amount of carbon, which is one of the raw materials for producing silicon carbide; Secondly, asphalt has cold solidification and thermoplasticity, and after heating, it has good plasticity, making it easy for the rod to shape when cooled; Thirdly, the material sources are extensive and economical.

In the production of equal diameter silicon carbide rods, resin is also used as a binder. This method can eliminate the need for mixing and heating devices during the molding process, but requires an additional drying device after molding, and the resin price is relatively expensive. Using asphalt or resin as binders can cause serious environmental pollution. Therefore, from the perspective of labor protection and environmental protection, some people have also attempted to use other materials as binders, but further research is needed.