Large‑Particle Spherical Fused Silica Powder CAS 7631‑86‑9 is amorphous fused silica produced by high‑temperature flame spheroidization of high‑grade quartz, followed by screening and air classification. The particle size is controlled above 40μm. Thanks to low specific surface area, the large spherical particles require less resin for surface wetting. It is used as high‑loading mineral filler for thick‑section casting resin and electrical potting compound, cutting resin dosage, moderating curin

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Large‑Particle Spherical Fused Silica Powder CAS 7631‑86‑9, >40μm for Casting Resin Potting Compound & High‑Loading Filler

This large‑particle spherical fused silica powder is manufactured from high‑quality quartz raw material through high‑temperature flame fusion and spheroidization. Subsequent multi‑stage sieving and air classification remove fine particle fractions and angular debris, yielding amorphous spherical silica particles with particle size greater than 40μm. The particle morphology is smooth and rounded without sharp edges.

Compared with fine micron and sub‑micron fused silica grades, this large‑particle silica possesses a markedly lower specific surface area. Less resin is consumed for wetting particle surfaces, which makes extremely high filler loading feasible within resin systems. Higher filling percentage effectively reduces overall resin consumption and raw‑material costs for thick castings. The spherical geometry decreases internal friction inside resin‑filler slurry, supporting acceptable fluidity even at high loading levels. Its amorphous silica structure delivers low coefficient of thermal expansion, which reduces curing shrinkage and improves dimensional stability for bulky, thick‑wall resin parts.

For casting resin applications, especially thick‑section epoxy cast components, high filler content suppresses the exothermic peak generated during epoxy cross‑linking curing. This effect helps avoid internal thermal cracking caused by excessive localized heat buildup inside large cast blocks.

In electrical potting compound formulations for heavy‑duty electrical modules, transformers and high‑voltage insulation assemblies, this large‑particle fused silica filler increases compressive strength and hardness of cured potting resin. It improves thermal conductivity of the composite system to assist heat dissipation and enhances long‑term insulating performance under continuous operating conditions. This grade is not suitable for fine‑gap molding, precision EMC encapsulation or thin‑layer coating due to its large particle dimension.

During compounding operations, low‑to‑moderate stirring speed is recommended. Excessively high‑shear mixing should be avoided, as powerful mechanical agitation may fracture large spherical particles and generate unwanted fine fragments. Filler loading needs careful formulation evaluation. Although high loading is desirable, over‑addition will cause poor slurry flow and particle sedimentation during curing, resulting in uneven filler distribution and sediment layers at the bottom of cast molds.

Sedimentation control is a critical formulation consideration for liquid potting slurry. Appropriate thixotropic additives are often required to retard particle settling before resin gelation. The powder shall be stored inside sealed moisture‑proof packaging in a dry warehouse. Cross‑contamination with fine silica grades must be prevented during material handling, because mixed fine fractions will alter slurry rheological behavior. This large‑particle spherical fused silica powder is an economical high‑loading mineral filler dedicated to thick‑section casting resin and heavy‑duty electrical potting compound.

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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.