Q
What is the maximum operating temperature of fused quartz glass?
Fused quartz glass can withstand up to 1300°C for short-term use and 1100°C for long-term continuous operation. Its softening point is 1780°C, and thermal processing is typically carried out between 1750°C and 2050°C, making it one of the most heat-resistant glass materials available.
Q
Why does fused quartz glass have such a low thermal expansion coefficient?
Fused quartz is composed of pure Silicon Dioxide (SiO₂) derived from natural quartz. Its amorphous three-dimensional network structure restricts atomic displacement under heat, resulting in an extremely low thermal expansion coefficient of just 5.5×10⁻⁷ cm/cm·°C — roughly 15 times lower than ordinary glass — giving it exceptional resistance to thermal shock.
Q
What thickness and shape options are available?
The fused quartz glass is available in circular (round) shapes with thicknesses ranging from 2mm to 20mm. This range covers a broad spectrum of industrial, optical, semiconductor, and scientific applications where precise dimensional control is required.
Q
What purity grades are available, and how does PPM affect performance?
Three controlled purity grades are offered: 10 PPM, 20 PPM, and 100 PPM. Lower PPM values indicate higher purity with fewer metallic impurities, which is critical for semiconductor wafer processing, photomask substrates, and high-precision optical components where even trace contamination can affect yields or optical performance.
Q
How hard is fused quartz glass, and is it prone to scratching?
Fused quartz glass has a Mohs hardness of 5.5 to 6.5, placing it between apatite and feldspar. This provides good resistance to everyday abrasion in laboratory and industrial environments. However, it can be scratched by harder materials such as corundum (Mohs 9) or diamond (Mohs 10), so care should be taken during handling and storage.
Q
Is fused quartz glass optically clear, and what are its optical properties?
Yes. Fused quartz glass is fully transparent and colorless, with an index of refraction of 1.4585. Each piece is produced with no air bubbles and no internal flow lines, ensuring optical-grade clarity. These properties make it ideal for UV-transmitting windows, precision lenses, laser optics, and observation viewports in high-temperature or vacuum environments.
