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With the rapid development of large AI models and computing centers, the power density of AI servers continues to surge, with single-GPU power consumption surpassing 700W. Consequently, heat dissipation has become a critical bottleneck constraining computing power escalation. As core thermal interface materials (TIMs) between chips and heatsinks, the thermal performance of thermal conductive silicone grease and thermal pads directly depends on the quality of alumina fillers. Many thermal material manufacturers are asking: How should alumina be selected for AI server heat dissipation?
Why Does AI Server Heat Dissipation Demand Higher Requirements for Thermal Conductive Alumina?
The power density of GPU chips in AI servers is far higher than that of traditional servers, with interfacial thermal resistance between the chip and heatsink accounting for up to 30%50% of the total thermal resistance. To minimize interfacial thermal resistance, thermal interface materials (TIMs) must exhibit higher thermal conductivity (typically requiring ≥ 5 W/(m·K), and ≥ 8 W/(m·K) for highend applications), lower thermal impedance, and superior wetout performance. This demands that alumina fillers possess: higher purity to ensure intrinsic thermal conductivity; higher sphericity to achieve high loading levels; optimized particle size distribution to enable packing limit efficiency; and lower oil absorption to reduce system viscosity.
The typical specifications for Shandong Greatsun Aopeng highthermalconductivity alumina are: Al₂O₃ ≥ 99.8%, Fe₂O₃ ≤ 0.01%, Na₂O ≤ 0.06%, particle size D₅₀ available in multiple grades from 150 μm, surface area (BET) 18 m²/g, oil absorption ≤ 25 g/100g, thermal conductivity ≥ 30 W/(m·K) (powder intrinsic value), volume resistivity ≥ 10¹⁵ Ω·cm, and Mohs hardness 9.
Highend applications such as AI servers, 5G base stations, and new energy vehicle IGBTs impose strict requirements on the purity and particle size distribution of alumina, typically utilizing a multimodal formulation strategy combining large and small particle sizes. Shandong Greatsun Aopeng offers a four tier multimodal formulation scheme comprising D50 values of 40 μm + 20 μm + 5 μm + 1 μm, achieving maximum packing density to optimize thermal conductivity.
When a leading domestic thermal material manufacturer developed highthermalconductivity pads for AI server GPU modules, they incorporated Shandong Greatsun Aopeng alumina (D50 40 μm + 5 μm + 1 μm threetier formulation) as filler. Achieving a loading level of 88 wt%, the resulting thermal pad exhibited a thermal conductivity of 6.5 W/(m·K) and a thermal resistance of ≤ 0.15 °C·in²/W (under 25 psi), while maintaining a Shore hardness of 6575 for excellent compressibility and interfacial wetout capability. Deployed in the GPU cooling module of an AI server, this thermal pad reduced the GPU junction temperature by 12 °C under a 700W power load, enabling stable server operation at higher clock frequencies and boosting computing power output by approximately 8%. Positioned between the cold plate and chips in liquidcooled servers, the product demonstrates equally outstanding performance and has passed reliability testing with multiple server manufacturers.
The core advantages of Shandong Greatsun Aopeng thermal conductive spherical alumina include: First, high purity, with Al₂O₃ ≥ 99.8% and low impurity levels of Fe, Na, etc., delivering high intrinsic thermal conductivity without compromising insulation performance; Second, a comprehensive range of particle size specifications, offering over a dozen grades with D50 from 1 μm to 50 μm, as well as customized blending solutions tailored to customer formulas; Third, low oil absorption, ≤ 30 g/100g, enabling ultrahigh loading levels while keeping system viscosity controllable; Fourth, superior electrical insulation, with volume resistivity ≥ 1015 Ω·cm and high dielectric breakdown strength, making it suitable for all types of highvoltage electronic components; Fifth, lottolot stability, having passed supplier certification for multiple publicly listed thermal material companies. For detailed technical solutions and sample testing of spherical alumina for AI server heat dissipation, please contact Shandong Greatsun Aopeng.
