With rapid development of space computing infrastructure (e.g. Musk's proposed space AI servers), thermal management materials face extreme environment challenges. Based on sp²–sp³ interconnected all-carbon composite (thermal conductivity 800–1500 W/m·K), this article analyzes its performance advantages in space applications, comparing with diamond-copper and other traditional solutions (copper or aluminum heat sinks). The material excels in lightweight, radiation resistance and thermal stability, suitable for space high-power GPU deployment.
Space imposes stringent requirements: vacuum allows only radiation (no convection/conduction); severe temperature fluctuation (-270°C to +120°C); high-energy radiation causes material degradation; zero gravity requires self-supporting, lightweight materials.
Traditional diamond-copper (600–1000 W/m·K) has good thermal conductivity but high density (5–7 g/cm³) and radiation sensitivity limit application. All-carbon composite locks internal stress through high-pressure process, forming continuous distorted interfaces, effectively addressing these challenges.
Typical process for sp²–sp³ interconnected all-carbon composite heat sink: Raw material: Pre-graphitized nanodiamond (40–60 wt%) as sp³ phase, graphene/carbon nanotubes (15–55 wt%) as sp² host. Forming: SPS sintering (0.8–6.0 GPa, 900–1200°C) for bulk heat sink (10–20 mm thick), surface conformal to satellite GPU layout. Surface optimization: Radiation coating (e.g. blackbody) for emissivity >0.9. Integration: Heat sink bonded to GPU via TIM, external radiation panel for heat removal.
All-carbon composite shows multiple advantages in space: Weight: Density 2–3 g/cm³ (1/2–1/3 of diamond-copper 5–7 g/cm³), launch cost halved ($100+/kg). Radiation tolerance: All-carbon more stable to high-energy radiation, thermal conductivity degradation <10% (diamond-copper 20–30%). sp³ phase has strong damage resistance. Thermal stability: Large temperature range (-200°C to +500°C), locked internal stress (10–60 GPa) prevents thermal cycle cracks. Diamond-copper CTE mismatch causes interface failure. Thermal efficiency: Comparable or higher (800–1500 W/m·K), better heat spreading (sp² network). High emissivity (0.8–0.95) improves radiation heat removal 15–25%. vs others: Aluminum (2.7 g/cm³) poor radiation tolerance; ceramic (AlN) brittle. All-carbon combines lightweight and toughness.
Despite advantages, all-carbon needs attention to strength (flexural 200–500 MPa) and conductivity (insulation coating). Optimization includes increasing sp³ ratio or surface shielding for radiation life.
All-carbon composite's lightweight, radiation-resistant and efficient heat diffusion properties in space thermal management make it superior to diamond-copper and traditional solutions. This solution provides reliable support for space AI computing, worthy of further R&D validation.