Heat-Conductive Silicone Composition for CPU Thermal Interface Gaps

The patent employs a composite filler system combining silver powder (high thermal conductivity: 429 W/mK) with aluminum nitride powder (70-270 W/mK) and zinc oxide powder (17-37 W/mK). This multi-material composite approach creates synergistic effects where silver provides exceptional thermal conduction pathways while aluminum nitride and zinc oxide fill interstitial spaces and contribute additional conduction routes, achieving thermal conductivity of 8.0 W/mK or higher in the grease composition that exceeds any single filler material's performance in this application context.

The patent systematically optimizes critical parameters including silver powder particle size distribution (combining fine particles of 0.1-10 μm with coarse particles of 10-100 μm), filler content (30-80 wt% total filler), and grease consistency (viscosity 10-1000 cP). These parameter changes transform the thermal conduction mechanism by creating dense filler packing with minimized void spaces, maximizing thermal contact between filler particles and enabling the grease to achieve sufficient heat dissipation for modern CPUs.

The patent maintains grease consistency within the optimal range of 10-1000 cP by carefully controlling the total filler content at 30-80 wt% and selecting base grease viscosity accordingly. This parameter optimization ensures the grease remains sufficiently fluid for easy application while containing enough filler to achieve the required thermal conductivity of 8.0 W/mK or higher, resolving the contradiction between thermal performance and ease of operation.

The patent employs a bimodal particle size distribution strategy where fine silver powder particles (0.1-10 μm) fill the interstitial spaces between larger aluminum nitride and zinc oxide particles (10-100 μm). This local quality differentiation creates a dense, space-efficient packing structure that maximizes thermal conduction pathways while minimizing the total volume occupied by filler, thereby maintaining better grease consistency and workability at higher filler loadings.

The patent creates a hierarchical filler structure where fine silver powder particles (0.1-10 μm) are distributed within and between larger aluminum nitride and zinc oxide particles (10-100 μm). This local quality differentiation allows fine particles to occupy interstitial voids and create additional thermal conduction pathways without significantly increasing overall viscosity, as the larger particles provide a skeletal framework that prevents excessive fine particle aggregation and maintains grease fluidity.

The multi-component filler composite (silver + aluminum nitride + zinc oxide) with differentiated particle sizes creates a synergistic structure where each component serves multiple functions: fine silver particles provide high-conductivity pathways, larger particles provide structural framework, and the combination maintains optimal viscosity by preventing excessive fine particle content that would otherwise increase handling difficulty.