Le rôle de l'oxyde de magnésium dans les matériaux isolants

Le rôle de l'oxyde de magnésium dans les matériaux isolants

1. Enhancing the Electrical Insulation Performance of Materials

• Blocking Current Conduction: Magnesium oxide itself has an extremely high volume resistivity (usually above 10¹⁴Ω·cm). When added to insulating materials (such as insulating paints, insulating papers, and cable insulation layers), it can effectively block current leakage or breakdown, enhance the dielectric strength (voltage breakdown resistance) of the material, and ensure the safe operation of electrical equipment in high-voltage environments.
• Suppressing Partial Discharge: In high-voltage insulating materials, magnesium oxide can be uniformly dispersed in the matrix, reducing defects such as bubbles and impurities inside the material, and alleviating the phenomenon of local electric field concentration. This suppresses the erosion of insulating materials by partial discharge and prolongs the insulation life.

2. Improving High-Temperature Resistance and Thermal Stability

• High-Temperature Carrier Function: Magnesium oxide has a melting point as high as 2800°C and is not easy to decompose or deteriorate at high temperatures, making it an ideal additive for high-temperature insulating materials. For example, in fire-resistant insulated cables, magnesium oxide is often used as an inorganic insulating filler to wrap conductors and form a high-temperature-resistant insulating layer. This allows the cable to maintain insulation performance in high-temperature environments above 600°C, making it suitable for extreme working conditions such as metallurgy and aerospace.
• Heat Conduction Regulation: Magnesium oxide has a certain degree of thermal conductivity. In insulating materials, it can help dissipate heat, avoiding aging of insulating materials caused by excessive local temperature during equipment operation (such as softening and decomposition of rubber or plastic insulation layers due to overheating), and balancing insulation and heat dissipation.

3. Improving Mechanical and Chemical Stability

• Enhancing Mechanical Strength: In insulating composite materials (such as glass fiber-reinforced insulating boards and molded insulating products), magnesium oxide can be used as a filler to combine with the matrix (resin, rubber, etc.), improving the hardness, tensile strength, and wear resistance of the material, and reducing damage to the insulation layer caused by mechanical stress.
• Corrosion Resistance and Moisture Resistance: Magnesium oxide is alkaline, which can neutralize acidic degradation products that may be generated during the use of insulating materials (such as organic acids released by polymer aging). At the same time, its dense structure can inhibit the penetration of water and moisture, protecting the insulating material from environmental corrosion. It is especially suitable for insulating products in humid or corrosive environments (such as underground cables and insulation layers of chemical equipment).

4. Adapting to Functional Requirements of Specific Insulation Scenarios

• High-Frequency Insulating Materials: In insulating materials for high-frequency motors and transformers, the low dielectric loss characteristic of magnesium oxide can reduce the conversion loss of electromagnetic energy, ensuring the efficiency and stability of equipment under high-frequency working conditions.
• Flexible Insulating Products: In flexible materials such as insulating rubber and insulating tape, magnesium oxide can adjust the vulcanization performance of the material (such as acting as a vulcanization activator), improving its aging resistance and insulation durability without affecting flexibility.
• Inorganic Insulating Coatings: Magnesium oxide can be compounded with other inorganic materials (such as aluminum oxide and silicon dioxide) to form ceramic insulating coatings, which are used on the surface of electrical components and have the functions of insulation, fire resistance, and wear resistance.

Summary