Large‑Particle Spherical Alumina Powder CAS 1344‑28‑1 is coarse dense alpha‑phase spherical alumina produced via high‑temperature plasma spheroidization, air classification and granular sieving. Particle size is controlled above 40μm. The smooth spherical bead morphology reduces resin slurry viscosity even at high filling levels. It is used as primary coarse filler for electronic potting compound and thermally‑conductive casting resin, raising packing density, enhancing heat dissipation and opti

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Large‑Particle Spherical Alumina Powder CAS 1344‑28‑1, >40μm for Potting Compound Casting Resin & High‑Loading Filler

This large‑particle spherical alumina powder is manufactured from high‑purity alumina feedstock through high‑temperature plasma fusion, droplet spheroidization, multi‑stage air classification and granular screening. The finished product consists of dense spherical α‑Al₂O₃ beads with particle size greater than 40μm. Oversized agglomerated lumps are removed during sieving operations.

Compared with irregular coarse crushed alumina, the spherical bead structure minimizes inter‑particle friction within liquid resin. It enables extremely high inorganic loading while keeping acceptable slurry fluidity for casting and potting processes. Dense alpha‑alumina crystal provides stable high thermal conductivity and reliable electrical insulation. This coarse fraction is the major skeleton component for multi‑modal ternary filler blends, where fine and submicron alumina grades fill the inter‑bead void spaces.

For electronic potting compound applications, this large‑particle spherical alumina is blended into epoxy or silicone potting systems for power modules, transformers and high‑voltage electronic assemblies. High filler loading improves overall thermal conductivity of the cured potting block, accelerates internal heat dissipation and reduces thermal expansion of the resin matrix. It suppresses thermal‑stress‑induced cracking inside thick potting layers under cyclic temperature changes.

For thermally‑conductive casting resin, the coarse spherical beads form the main thermal‑conductive framework. When properly compounded with medium and fine alumina fractions, maximum packing density can be achieved. This significantly lifts thermal performance of thick cast resin parts for power electronics. Due to its large particle dimension, this grade is not suitable for thin‑layer coating, fine screen‑printing or miniaturized semiconductor EMC encapsulation, where coarse beads may cause surface defects or scratching on tiny chip structures.

Surface silane modification is available upon request. Surface treatment improves wet‑out between spherical alumina and liquid resin matrix, reduces trapped micro‑voids at the particle‑resin interface and enhances mechanical strength of cured casting composites.

During slurry mixing, moderate‑speed stirring is recommended. Vigorous high‑shear agitation must be strictly avoided. Strong mechanical collision will fracture the large spherical beads, generating sharp fine fragments, which would increase slurry viscosity and wear mixing equipment.

Formulation trials are essential to determine optimal loading ratio. Excessive dosage of large‑particle beads will deteriorate the flowability of liquid potting and casting resin, leading to poor filling for narrow gaps inside electronic assemblies. When constructing multi‑modal filler formulas, matching proportions with medium and fine alumina fractions should be tested thoroughly.

The powder should be stored in hermetically sealed, moisture‑proof packaging inside a dry warehouse. Adsorbed moisture will introduce trapped bubbles during resin curing. Physical segregation from medium, fine and submicron alumina fractions must be maintained during storage and feeding to prevent cross‑contamination of particle‑size fractions, which would destroy the designed gradation effect for high‑loading formulas. This large‑particle spherical α‑alumina serves as a primary coarse thermally‑conductive skeleton filler for electronic potting compound, casting resin and high‑loading polymer composites.

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Large-Particle Spherical Alumina Powder CAS 1344-28-1, >40μm for Potting Compound Casting Resin & High-Loading Filler

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Jishengya Technology

Shenzhen Jishengya Technology Co., Ltd. is located in Shenzhen, a special economic zone, and is a comprehensive technology enterprise integrating independent R&D, production and sales.