According to Messi Biology, magnesium oxide (MgO) has evolved from a supporting role to a “multi-spectral stealth core material” in modern stealth technology. Its latest military-grade applications can be summarized as “three-band stealth + structural-functional integration.” With its “lightweight, broadband, and structurally integratable” advantages, MgO has become a cornerstone material for multi-spectral stealth for advanced equipment such as stealth fighters, missiles, and hypersonic aircraft.
1. Radar Stealth: Lightweight Broadband Absorber
- Mechanism: Nano-MgO (particle size 20–50nm), with its high specific surface area and abundant defects, converts electromagnetic energy into thermal energy through dielectric polarization + interface relaxation in the 2–18GHz frequency band. The reflection loss can reach –30dB, and a coating thickness of <0.5mm can reduce the RCS by 10dBsm.
- Real-world Applications:
- Composite Coating: A three-layer structure of MgO/CNT/polysiloxane has been applied in batches to the skin of a certain type of UAV, with a surface density of <0.6kgm⁻².
- Structural Components: Composited with quartz fiber to form a radome, switching between wave transmission and stealth, balancing detection and concealment.
2. Infrared Stealth: Dynamic Emissivity Control
- Band Coverage: Through MgO-based multi-layer films (MgO/VO₂/MgF₂), the emissivity can be dynamically adjusted between 0.2–0.8 in the 3–5µm and 8–14µm dual atmospheric windows, reducing the infrared signature of a tank’s side armor by 80%.
- Heat Dissipation Synergy: High thermal conductivity MgO layers (>50Wm⁻¹K⁻¹) can quickly conduct heat away from engine hotspots laterally, suppressing the formation of infrared hotspots.
3. Visible Light-Near Infrared Stealth: Environmentally Adaptive Camouflage
- High Whiteness + Refractive Index Matching: MgO has a refractive index of n≈1.74, with near-zero dispersion matching snow and desert backgrounds; its nano-porous structure gives it an average reflectivity of >92% in the 400–900nm range, resulting in a color difference of ΔE<1.2 for snow camouflage.
- Composite Formulation: MgO/Al₂O₃/fluororesin coatings are used for polar missile launchers, maintaining flexibility at –40℃, and showing no powdering after 1000h of UV aging.
4. Structural-Functional Integration: Stealth-Thermal Protection Dual Effect
- Hypersonic Application: Embedding a gradient MgO nanowire array in a C/SiC heat shield absorbs radar waves (8–12GHz RL<–25dB) and withstands aerodynamic heating with a melting point of 2852℃. This has been flight-tested on a certain wave-riding experimental vehicle.
- Armor Protection: MgO/PEEK composite armor simultaneously achieves radar stealth (Ku-band RL<–20dB) and fragment protection (V50>600ms), with a surface density 30% lower than traditional armor.
Application Scenarios
- Cross-Band Compatibility: MgO/graphene/VO₂ metasurfaces achieve simultaneous stealth in the radar, infrared, and visible light bands.
- Intelligent Stealth: Electric field control of surface charge on MgO allows the stealth coating to switch between “stealth-detection” in milliseconds, adapting to future electronic warfare needs.