The properties of Spherical Alumina Powder
Spherical alumina Powder has the following significant advantages as a thermal conductive material compared to other forms of alumina (such as irregular particles, flakes or fibers). Especially in thermal conductive composite materials (such as thermal conductive silicone grease, plastics, ceramics, etc.).
Here are properties of spherical alumina powder：
1. Higher thermal conductivity
Low thermal resistance path: Spherical particles can form a denser stack in the matrix, reduce the interface thermal resistance, and heat is efficiently transferred through the contact points of the spheres.
Isotropic thermal conductivity: The spherical structure makes the thermal conductivity path evenly distributed, avoiding the uneven local thermal resistance caused by the orientation differences of irregular particles.
2. Excellent filling and fluidity
High filling density: Spherical particles achieve a higher filling rate (up to 70% or more) through geometric advantages (such as the densest packing), reduce the proportion of matrix materials, and improve the overall thermal conductivity.
Low viscosity processing: Spherical particles have good fluidity and are easier to disperse in polymers (such as epoxy resins and silicone), reducing bubbles and voids, and are suitable for injection molding, coating and other processes.
3. Mechanical property optimization
Low stress concentration: The spherical structure avoids damage to the matrix by sharp edges (such as silicone tearing), and improves the flexibility and durability of the composite material.
Enhanced mechanical strength: Evenly dispersed spherical particles can improve the compression and shear resistance of composite materials (such as thermal conductive gaskets).
4. Interface bonding advantages
Fewer defects: The spherical surface is smooth, with a large contact area with the matrix and fewer interface defects, reducing phonon scattering (key to thermal conductivity) and improving the interface thermal conduction efficiency.
Surface modification compatibility: Spherical particles are easier to improve compatibility with organic matrices through treatments such as silane coupling agents.
5. Application scenario adaptability
Electronic device heat dissipation: used for high-power LEDs and CPU heat dissipation interface materials (TIM), requiring low thermal resistance and high reliability.
Lightweight requirements: Compared with metal fillers (such as silver and aluminum), spherical alumina is insulating and has low density, suitable for aerospace electronics.
Precision molding: Spherical particles are suitable for 3D printing thermal conductive ceramics or high-precision injection molding parts (such as heat dissipation housings).
In short, spherical alumina powder has become the preferred filler for high thermal conductivity insulation materials due to its geometric characteristics and physical properties, especially in the electronics field that requires efficient heat dissipation and reliability.
