COMPARISON OF THE CHARACTERISTICS OF DIFFERENT TYPES OF SILICON CARBIDE SEALS

In the modern industrial field, the role of seals is crucial. It can effectively prevent fluid or gas leakage and ensure the normal operation and safety of the equipment. As a high-performance material, silicon carbide has been widely used in the field of seals. Different types of silicon carbide seals have their own unique characteristics, which will be compared and analyzed below.

1. Reaction sintered silicon carbide seal

Reaction sintering silicon carbide is made by reacting silicon carbide powder and toner powder with silicon vapor at high temperature. This kind of seal has the following characteristics:

1). High strength and high hardness: Reaction sintered silicon carbide seals have extremely high strength and hardness, can withstand greater pressure and wear, and are suitable for harsh working environ

2). Good chemical stability: It has strong tolerance to acids, alkalis, salts and other chemicals, is not easy to be corroded, and can work stably in various chemical media.

3). Excellent thermal conductivity: high thermal conductivity, which can quickly dissipate heat and avoid damage to the seal due to overheating.

4). High dimensional accuracy: Adopting advanced manufacturing technology, it can ensure the dimensional accuracy of the seal and improve the sealing performance.

However, there are also some shortcomings in reaction sintered silicon carbide seals. For example, its manufacturing process is relatively complex and the cost is high; oxidation may occur at high temperatures, affecting its performance and service life.

2. Pressureless sintered silicon carbide seals

Pressureless sintered silicon carbide is made by solid phase sintering at high temperature. The characteristics of this seal are as follows:

1). High purity: The purity of pressureless sintered silicon carbide seals is high and the content of impurities is low, which can ensure the stability and reliability of its performance.

2). Good wear resistance: high hardness, good wear resistance, and can maintain sealing performance for a long time.

3). Low thermal expansion coefficient: The thermal expansion coefficient is small, and the size change is small when the temperature changes, which is conducive to improving the reliability of sealing

4). Good processability: relative reaction sintered silicon carbide, pressureless sintered silicon carbide has better processability, and can be processed by traditional processing methods.

However, pressureless sintered silicon carbide seals also have some disadvantages. For example, its strength is relatively low, and it may crack when under great pressure; the manufacturing process requires a higher temperature and a longer time, and the cost is high.

3. Hot-pressed sintered silicon carbide seals

Hot-pressed sintered silicon carbide is made by liquid phase sintering under high temperature and high pressure. This kind of seal has the following characteristics:

1). Extremely high strength and hardness: The strength and hardness of hot-pressed sintered silicon carbide seals are the highest among the three types and can withstand great pressure and wear.

2). Good density: Through the hot pressing sintering process, the organizational structure of the seal is more dense, which can effectively prevent leakage.

3). Excellent high-temperature resistance: It can work at very high temperatures, which is suitable for high-temperature and high-pressure working environments.

4). Fast manufacturing process: Compared with the other two sintering methods, the manufacturing process time of hot pressing sintering is relatively short, which can improve production efficiency.

However, hot-pressed sintered silicon carbide seals also have their limitations. First of all, the manufacturing equipment is complex and the cost is high; secondly, because it is sintered under high pressure, the shape and size of the seal are limited to a certain extent.

4. Comparison of application scenarios of different types of silicon carbide seals

1). Reaction sintered silicon carbide seals are suitable for occasions with high requirements for sealing performance and harsh working environments, such as chemical industry, petroleum, metallurgy and other industries.

2). Pressureless sintered silicon carbide seals are suitable for occasions with high purity requirements and good wear resistance, such as semiconductors, electronics and other industries.

3). Hot-pressed sintered silicon carbide seals are suitable for high-temperature and high-pressure occasions with high requirements for strength and hardness, such as aerospace, nuclear energy and other industries.

In summary, different types of silicon carbide seals have their own unique characteristics and application scenarios. When selecting seals, the performance, cost, manufacturing process and other factors of the seal should be comprehensively considered according to the specific working conditions and requirements, and the most suitable type of silicon carbide seal should be selected to ensure the normal operation and safety of the equipment. With the continuous progress of science and technology, the performance of silicon carbide seals will continue to improve, and the scope of application will continue to expand.