Why can black silicon carbide be used as a raw material for lightning arrester valve plates?
The selection of black silicon carbide in the production of lightning arrester valve plates is mainly based on its unique physical and chemical properties. The specific reasons include the following:
1. Nonlinear resistance characteristics and electrical properties
Black silicon carbide has nonlinear conductivity characteristics, that is, the resistance is significantly reduced under high voltage and remains in a high resistance state under low voltage. This characteristic is consistent with the core function of the lightning arrester valve plate: it quickly conducts the discharge current when the lightning overvoltage occurs, and restores the high resistance state under normal voltage to block the power frequency continuous current.
Its high thermal conductivity (thermal conductivity of 120-160 W/m·K) and low thermal expansion coefficient can effectively disperse the high-energy impact of lightning strikes and avoid local overheating or material rupture.
2. Chemical stability and high temperature resistance
Black silicon carbide can remain stable at high temperatures (can withstand more than 1600℃) and corrosive environments, and is suitable for use in lightning arrester valve plates that frequently withstand high-voltage arcs and chemical erosion.
By adjusting the particle size and sintering process, its thermal shock resistance can be further enhanced to prevent material fatigue failure caused by sudden temperature changes.
3. Production process adaptability
Black silicon carbide can be made into a high-density valve plate structure through micro-powder coating, high-temperature sintering and other processes to meet the requirements of lightning arresters for material uniformity and mechanical strength. For example, the dynamic response performance of the valve plate can be optimized by uniformly coating the micro-powder on the surface of the ceramic substrate using the water plating method.
4. Economic efficiency and mature application
Compared with other semiconductor materials (such as zinc oxide), the preparation process of black silicon carbide is mature and low-cost, and after being compounded with materials such as alumina, the electrical performance of the valve plate can be further improved.
Summary
Due to its nonlinear resistance characteristics, thermal stability and process adaptability, black silicon carbide has become an ideal material for lightning arrester valve plates, ensuring reliable operation of the equipment under extreme conditions and extending its service life.