Produced in Donghai County with high-purity natural silica or synthetic fused silica. Designed for airtight vacuum seals, corrosive gas diffusion, and extreme operating temperatures.
Manufactured from clear fused silica with optical-grade surface finish and parallel edge grinding. Resists thermal shock and chemical erosion in high-vacuum heating chambers.
High-temperature resistant transparent quartz tube integrated with an annealed flange collar. Engineered for optical semiconductor processes, CVD furnaces, and vacuum connections.
Precision CNC-milled quartz flange disc with custom mounting hole patterns and polished bevels. Suitable for welding onto process reactor chambers or direct clamp assembly.
Low hydroxyl (low-OH) fused silica rings designed for aggressive semiconductor etching, CVD processes, and optical reflection mounts with optional custom coating.
Donghai County Nivra Quartz Products Co., Ltd. combines raw material selection in China's quartz capital with advanced multi-axis CNC milling, cold processing, and hydrogen-oxygen flame welding.
Complex counterbored holes, O-ring sealing grooves, and stepped profiles are machined with CNC diamond tools achieving outer diameter tolerances down to ±0.03 mm and flatness within λ/4.
Fused silica has a near-zero coefficient of thermal expansion (5.5 × 10⁻⁷ /°C). Our annealed quartz flange joints can transition from 1100°C to cold air without thermal shock failure.
Trace metal impurity levels are kept under 20 ppm across iron, aluminum, sodium, and potassium, preventing chamber contamination in wafer fabrication and high-purity chemical reactions.
Use these baseline physical metrics when designing quartz flange joints, sight glass ports, and vacuum furnace interfaces.
| Parameter | Standard / Test Condition | Technical Value |
|---|---|---|
| Silicon Dioxide (SiO₂) Purity | ICP-OES Chemical Analysis | ≥ 99.99% |
| Density | Room Temperature (20°C) | 2.20 ± 0.02 g/cm³ |
| Softening Point | Viscosity log η = 7.6 | ≈ 1683 °C |
| Continuous Operating Temperature | Clean oxidizing / vacuum condition | 1100 °C |
| Maximum Short-Term Exposure | Thermal cycling duration < 30 min | 1450 °C |
| Linear Thermal Expansion Coefficient | 20 °C to 300 °C | 5.5 × 10⁻⁷ /°C |
| Refractive Index (nd) | λ = 589.3 nm (JGS1 / JGS2) | 1.4585 |
| Chemical Stability | Acid immersion (except HF, H₃PO₄ > 300°C) | Extreme acid resistance, hydrolytic Class 1 |
| Available Machining Dimensions | Outer Diameter range | OD 15 mm to 800 mm, thickness 2 mm to 100 mm |
Donghai County Nivra Quartz Products Co., Ltd. manufactures standard KF/NW, CF, and ISO quartz flanges, as well as customized bolt-hole patterns, O-ring groove flanges, welded tube-flange assemblies, and stepped quartz sight rings according to customer CAD/STEP drawings.
Our fused quartz flanges withstand continuous working temperatures up to 1100°C and short-term peaks up to 1450°C. With an extremely low thermal expansion coefficient of 5.5 x 10^-7 /°C, they resist rapid thermal cycling without cracking.
Yes. Our CNC milling, ultrasonic drilling, and precision grinding facilities allow us to produce intricate counter-bored bolt holes, O-ring sealing grooves, and edge bevels with tight tolerances up to ±0.05 mm.
Standard samples require 3 to 7 working days, while bulk custom orders typically ship in 10 to 20 days. Every flange is ultrasonic cleaned, shrink-wrapped in a dust-free environment, cushioned with multi-layer high-density EPE foam, and packaged into reinforced wooden export crates.