Silicon carbide powder for thermal conductivity & heat dissipation
Silicon carbide (SiC) powder is a commonly used high-end powder in thermally conductive fillers, heat dissipation materials. Its main performance characteristics are concentrated in high thermal conductivity, low thermal expansion, high stability, high insulation, and ease of filling, specifically as follows:
1. High thermal conductivity, far exceeding that of alumina
– Theoretical thermal conductivity can reach 200–490 W/(m·K) (slight differences exist between different crystal forms; the thermal conductivity of alpha phase silicon carbide is higher than that of beta phase).
– In practical applications as a filler, its thermal conductivity is significantly higher than that of alumina (Al₂O₃). The improvement in thermal conductivity of composite materials is more significant at the same filler content.
2. Low coefficient of thermal expansion, good compatibility with semiconductors/ceramics
– The coefficient of linear expansion is approximately 3.5–4.5 × 10⁻⁶ /℃.
– It’s similar to silicon chips, ceramic substrates, and aluminum silicon carbide (AlSiC) packaging shells. It exhibits low thermal stress, strong thermal shock resistance, and is not prone to cracking due to thermal cycling.
3. Extremely Strong Chemical Stability and High Temperature Resistance
– It maintains structural stability at temperatures of 800℃ or even higher, without decomposition or deterioration.
– Resistant to acids and alkalis, and oxidation; it does not undergo harmful interfacial reactions with resins or metals at high temperatures. As a result, it is suitable for high-temperature heat dissipation and high-power device environments.
4. Good Electrical Insulation, Without Affecting Electrical Safety
– High-purity SiC powder has high volume resistivity, classifying it as a semi-insulating/insulating filler.
– It improves thermal conductivity without reducing insulation performance. Thus SiC powder is suitable for use in insulating thermally conductive adhesives, thermally conductive pads, and potting compounds.
5. High Hardness and Wear Resistance, Suitable for Long-Term Operating Conditions
– Mohs hardness is approximately 9.5, close to diamond.
– The material is wear-resistant and erosion-resistant, suitable for high-power, high-reliability heat dissipation structures and coatings.
In summary, the core advantages of SiC powder in the field of heat dissipation include high thermal conductivity, low thermal expansion, high temperature resistance, insulation, stability, and high filler capacity. It is a high-performance thermally conductive filler that can replace or be combined with alumina in scenarios such as high-power power supplies, new energy vehicle electronic control, IGBTs, optical modules, and high-end electronic packaging.
