热管理 化学品

Thermal management in electronics uses four main approaches: (1) thermal interface materials (TIMs) — conductive adhesives or greases filling air gaps between heat source and sink; (2) thermally conductive encapsulants that transfer heat from components to housing; (3) phase change materials (PCMs) that absorb peak loads through latent heat; (4) heat spreader coatings that redistribute heat across a larger area. Thermal conductivity ranges from 1 W/m·K (epoxies) to 6 W/m·K (filled systems).

Thermally conductive fillers — alumina (Al2O3), boron nitride (BN), aluminum nitride (AlN), and silicon carbide (SiC) — improve thermal conductivity but increase viscosity significantly and may reduce electrical resistivity. Loading levels of 50–80 vol% are typical for high-conductivity systems. Surface-treated fillers and bimodal particle size distributions improve packing efficiency and reduce viscosity at high loading. Processing requires careful deaeration to avoid void-related thermal resistance.

Radiative cooling coatings emit infrared radiation in the atmospheric transparency window (8–13 µm) while reflecting solar radiation (0.3–2.5 µm). This allows surfaces to cool below ambient temperature even under direct sunlight — achieving sub-ambient cooling of 5–10°C. Key materials include silica nanoparticles in PDMS matrices, polymer films with engineered IR emittance, and white paints with high solar reflectance (SRI > 100). Applications include cool roofs, energy-saving building envelopes, and outdoor equipment.