Fused Silica is a high-purity, non-crystalline (amorphous) form of silicon dioxide (SiO₂), produced by melting high-quality quartz at extremely high temperatures and rapidly cooling it. This process gives fused silica exceptional thermal stability, low thermal expansion, and excellent chemical purity.
Thanks to its unique physical and chemical properties, fused silica is widely used in industries that require high temperature resistance, thermal shock stability, and dimensional accuracy, especially in refractory, foundry, semiconductor, and precision casting applications.
Key Properties of Fused Silica
Extremely Low Thermal Expansion
One of the most outstanding properties of fused silica is its extremely low coefficient of thermal expansion. This allows it to withstand rapid temperature changes without cracking, making it ideal for applications exposed to thermal shock.
High Temperature Resistance
Fused silica can operate continuously at temperatures above 1000°C and withstand short-term exposure to even higher temperatures. It maintains structural stability and does not deform easily under extreme heat.
Excellent Chemical Purity
With very high SiO₂ content (typically ≥99.5%), fused silica exhibits excellent resistance to chemical corrosion. It performs well in acidic environments and is suitable for high-purity industrial processes.
Electrical Insulation
Fused silica is an excellent electrical insulator, even at elevated temperatures. This makes it suitable for electrical, electronic, and semiconductor applications.
Applications of Fused Silica
The superior properties of fused silica make it suitable for a wide range of industrial applications, including:
Foundry & Casting Industry
Investment casting:** Used as a primary and backup refractory material for shell molds
Precision casting:** Provides excellent surface finish and dimensional accuracy
Thermal shock resistance:** Ideal for repeated heating and cooling cycles
Refractory Applications
High-temperature linings:** Used in furnaces, kilns, and thermal equipment
Refractory shapes and mixes:** Suitable for high-performance refractory formulations
Semiconductor & Electronics
Semiconductor components:** Used in wafer processing equipment
Electrical insulation parts:** Stable under high temperature and high voltage
Glass & Chemical Industry
Specialty glass production:** Raw material for high-purity glass
Chemical processing:** Resistant to acids and aggressive environments
Installation and Handling
Fused silica products can be processed into powders, sands, or precision-shaped components depending on the application. During installation and handling:
Avoid contamination to maintain chemical purity
Follow proper storage and handling procedures to prevent moisture absorption
Use appropriate personal protective equipment when handling fine powders
Maintenance and Storage
Fused silica requires minimal maintenance. It should be stored in a dry, clean environment to preserve purity and performance. Proper packaging and storage help prevent contamination and ensure consistent quality during use.
Conclusion
Fused silica is a high-performance industrial material known for its low thermal expansion, excellent thermal shock resistance, and high chemical purity. These characteristics make it indispensable in foundry, refractory, semiconductor, and high-temperature industrial applications. By choosing fused silica, manufacturers and engineers can achieve greater reliability, precision, and performance in demanding environments.
Frequently Asked Questions About Fused Silica
1. What is the difference between fused silica and quartz?
Quartz is crystalline, while fused silica is amorphous. Fused silica offers much lower thermal expansion and better thermal shock resistance compared to natural quartz.
2. Can fused silica withstand rapid temperature changes?
Yes. Due to its extremely low thermal expansion, fused silica performs exceptionally well under rapid heating and cooling conditions.
3. Is fused silica chemically resistant?
Fused silica has excellent resistance to most acids and chemical environments, except hydrofluoric acid (HF), which can attack silica.
4. What is the price of fused silica?
The price of fused silica varies based on purity, particle size, and application. Typically, prices range from **USD 300 to 1,200 per metric ton**. Factory-direct supply and customized grades are available upon request.
