High thermal conductivity aluminum nitride ceramic circular sheet

In the context of high-power and integrated development of electronic devices, heat dissipation has become a key bottleneck restricting performance improvement. As an emerging thermal management material, high thermal conductivity aluminum nitride (AlN) ceramic circular sheets have shown broad application prospects in power semiconductors, LED lighting, 5G communication and other fields due to their excellent thermal conductivity, good electrical insulation and mechanical stability.

Thermal conductivity mechanism and material properties of aluminum nitride ceramics
Crystal Structure and Thermal Conductivity Mechanism
Aluminum nitride has a hexagonal wurtzite structure, where Al ³ ⁺ and N ³ ⁻ form [AlN ₄] tetrahedra through covalent bonds. Its theoretical thermal conductivity can reach 320 W/(m · K), and the actual product can reach 180-230 W/(m · K). High thermal conductivity originates from the efficient conduction of phonons (lattice vibrations), with an average free path close to the micrometer level, far exceeding the electronic thermal conductivity mechanism of metals.
Core advantages of materials
Thermal conductivity: 5-8 times higher than aluminum oxide (Al ₂ O ∝), close to beryllium oxide (BeO) but non-toxic and environmentally friendly;
Electrical insulation: Volume resistivity>10 ¹⁴Ω· cm, suitable for high-voltage electrical isolation scenarios;
Thermal expansion coefficient: matched with silicon (Si) and gallium arsenide (GaAs) (4.5-5.5 ppm/℃), reducing thermal stress;
Mechanical strength: Bending strength>300 MPa, suitable for thin design.
Key points of circular plate design
Diameter and thickness: Conventional size is 10-200mm, thickness is 0.2-5mm, supporting customized processing;
Surface treatment: metalization (gold plating, copper plating), laser drilling or grooving to enhance welding or heat dissipation efficiency;
Flatness: Surface roughness Ra<0.5 μ m ensures minimal interface thermal resistance.

Preparation process and key technologies
Powder synthesis
By using carbon thermal reduction method or self propagating high-temperature synthesis (SHS), the sintering activity is ensured by controlling the raw material purity (Al source ≥ 99.5%), particle size distribution (D50<1 μ m), and oxygen content (<500ppm).
Forming technology
Casting molding: suitable for thin sheets with a thickness of ≤ 0.5mm, achieving high-density green bodies by optimizing the viscosity of the slurry and dispersants (such as PVP);
Isostatic pressure forming: Combining molding and cold isostatic pressing (CIP), the density uniformity reaches ± 0.5%;
Injection molding: Integrated molding of complex structures, suitable for mass production.
agglomeration process
Atmospheric pressure sintering: adding sintering aids such as Y ₂ O3 and CaO, sintering at 1800-1900 ℃ in N ₂ atmosphere to promote grain growth;
Hot pressing sintering (HP): densification can be achieved at 1700 ℃ under pressure assistance, with grain size<2 μ m, improving thermal conductivity;
Atmosphere control: Dynamic N ₂/H ₂ mixed gas is used to suppress the oxidation and decomposition of AlN.
Post processing technology
Laser cutting: heat affected zone<50 μ m, edge collapse ≤ 10 μ m;
Chemical polishing: HF/HNO3 mixed acid treatment, surface roughness reaches Ra<0.1 μ m;
Metalization process: Magnetron sputtering or electroplating deposition of Cu/Au layer, with a controllable thickness of 1-10 μ m.

As a new generation of thermal management materials, the performance advantages of high thermal conductivity aluminum nitride ceramic circular sheets are becoming increasingly prominent in the high-density process of electronic devices. Through material design, process optimization, and cross disciplinary collaborative innovation, it is expected to play a greater role in strategic fields such as new energy vehicles, artificial intelligence, and aerospace in the future, becoming a key puzzle to solve the “hot bottleneck”.