Fused silica

Fused silica (CAS 60676-86-0, EC 262-373-8, formula O2Si) is the amorphous, noncrystalline form of silicon dioxide, produced by melting high-purity quartz at extreme temperatures. It is traded under designations including SGA, RD8, F44, Y40, and GP7I, and carries no assigned E-code. It is classified under HS code 28112200.

In electronics manufacturing, fused silica is used as a filler in epoxy encapsulants, where its low thermal expansion coefficient reduces mechanical stress on semiconductor components. In building and construction, it functions as a functional filler in sealants and coatings, modifying surface wetting behavior and improving adhesion to substrates. The paper industry uses it to control ink receptivity on coated surfaces.

Fused silica is supplied in amorphous powder and rod forms across multiple purity grades and is subject to REACH registration requirements for EU market supply. Procurement teams should confirm SDS compliance and particle size specification when sourcing for electronics-grade or construction-grade applications.