1，Production Process ：

Reaction sintering process: the carbon source and silicon carbide powder are mixed, and the billet is prepared by grouting molding, dry pressing or cold

 isostatic pressing. Then in a vacuum or inert atmosphere, the body is heated to more than 1500℃, the solid silicon melts into liquid silicon, through capillary

 action into the body containing pores, liquid silicon or silicon vapor and the carbon in the body of the chemical reaction between the β-SiC and the original 

SiC particles in the body, the formation of reaction-sintered silicon carbide ceramic material.

Oxide sintering process: usually 5%-10% of SiO₂ micro-powder or quartz fine powder and SiC particles are co-ingredients, and sometimes a flux is added, 

pressed and formed in a general kiln. In the process of firing and use, the film formed by the oxide is wrapped on the SiC particles and plays a binding role

2，Application Area

Reaction Sintering: It is often used in high temperature kiln utensils, such as kiln shed board, bracket, etc. Radiation tube, used as a component of radiation 

heating in equipment such as heat treatment; Heat exchanger, used in various chemical, energy and other fields that need heat exchange; Desulfurization nozzle,

 used in flue gas desulfurization and other environmental protection equipment

oxide sintering: widely used in kiln shed for firing porcelain, etc. In some of the high temperature performance requirements are not extremely harsh, but need 

a certain antioxidant chemical reaction vessels, pipelines and other lining; It can also be used for supporting parts in some ordinary heat treatment furnaces

Reactive Sintering Advantage：

Simple process and low cost: compared with some other sintering methods, such as hot pressing sintering, reaction sintering process is relatively simple, does 

not require complex high pressure equipment, etc., and the production cost is relatively low.

Near-net size molding: can prepare near-net size products, almost no shrinkage and size change in the sintering process, suitable for the preparation of large size,

 complex shape of silicon carbide ceramic products, can reduce the amount of subsequent processing.

Excellent performance: with high hardness, Mohs hardness reached 9.5, second only to diamond, wear resistance; High strength, can achieve good compressive 

and bending strength; Excellent thermal conductivity, thermal conductivity up to 120-200 W/(m · K); Low thermal expansion coefficient, only 4.5×10⁻⁶ K⁻¹, good thermal

 shock resistance; At high temperature, the surface can form a dense silica protective layer, which has good oxidation resistance and excellent resistance to acid, alkali 

and molten metal.

Disadvantage

Limited high temperature performance: there is free silicon in the material, when the temperature exceeds 1400 ° C, the free silicon melts, which will lead to a rapid

 decline in the strength of the material, limiting its application in higher temperature environments.

Brittleness problem: Due to the high brittleness and other characteristics of silicon, reaction-sintered silicon carbide as a whole still has a certain brittleness, easy to 

brittle fracture, which may affect its service life in some high impact and high vibration environments.

Strict control of raw materials and processes: the purity of raw materials, particle size distribution, carbon source content and other requirements are strict, and in the

 molding and sintering process, temperature, pressure, atmosphere, time and other parameters need to be precisely controlled, otherwise it is easy to appear too high 

porosity, too much free silicon residue, cracks and other defects, affecting product quality.

Oxide sintering Advantage

The process is simple: usually the oxide and silicon carbide particles are mixed together, pressed and formed in the general kiln firing, do not need to be as reaction sintering

 as the need to precisely control the special process such as siliconizing, the preparation process is relatively simple

Good oxidation resistance: In the process of firing and use, the oxide will form a protective film wrapped on the silicon carbide particles, which improves the oxidation 

resistance of the material to a certain extent, and can remain relatively stable under a certain high temperature environment

Low cost: The raw material cost is relatively low, and the process is simple, so the overall production cost is usually lower than the reaction-sintered silicon carbide.

Disadvantage

Limited high temperature performance: Because the oxide is easy to creep at high temperatures, the high temperature strength and thermal shock resistance of the material 

are relatively poor, and the use temperature is generally between 1673-1773K (about 1400-1500℃), compared with some other sintered silicon carbide materials, the high 

temperature performance has a certain gap.

Mechanical properties are general: the bending strength is about 20-25MPa, compared with reaction-sintered silicon carbide, its mechanical properties such as hardness, strength 

and so on are relatively low, in the application scenario with high mechanical properties requirements may not meet the demand.

Difficult to improve density: Compared with reactive sintering and other methods, it is difficult to obtain high density sintered body, there may be more pores and other defects,

 which will affect the corrosion resistance, wear resistance and other properties of the material

How do we choose our own silicon carbide protective tube?

Cost: The production cost of reaction-sintered silicon carbide protective tubes is relatively low because of its low sintering temperature. Oxide sintered silicon carbide tube 

production may require the addition of specific additives or special treatment, the cost may be slightly higher.

Manufacturing process: Reaction sintering is a near-net size sintering process, there is almost no shrinkage and size change in the sintering process, suitable for the preparation

 of large size and complex shape of silicon carbide ceramic products, but the prepreparation process is more complex. The preparation process of oxide-sintered silicon carbide is

 relatively simple, and a variety of molding processes can be used to meet the needs of products of different shapes and sizes

Large size and complex shape: For large size and complex shape of silicon carbide protective tube, reaction sintering process is more suitable, because of its near-net size sintering

 characteristics, can effectively reduce the amount of subsequent processing

Small size simple shape: small size, simple shape of the protective tube, both sintering methods can achieve good forming effect, can be selected according to other performance

 requirements and cost and other factors.

High temperature environment: If the use temperature is below 1350℃-1380℃, reaction sintering and oxide sintering silicon carbide protective tube can be considered, but more

 than 1400℃, it is more appropriate to choose oxide sintered silicon carbide protective tube.

Chemical corrosion environment: in a strong acid and alkali environment, oxide-sintered silicon carbide protective tubes are usually more advantageous because of their better

 chemical stability; In general weak corrosion or no corrosion environment, both can be applied.

Temperature fluctuation environment: If there are frequent temperature changes during use, the thermal shock resistance of reaction-sintered silicon carbide protective tube 

makes it more suitable; If the temperature fluctuation is relatively small, the oxide sintered silicon carbide protective tube can also meet the requirements