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High-Temperature Quartz Seals and Gaskets

High-Temperature Quartz Seals and Gaskets

-- Steady & Reliable Manufacturer --

Introduction

High-Temperature Quartz Seals and Gaskets are specialized components used to create airtight, chemically resistant, and thermally stable interfaces between quartz and other materials (e.g., metal, ceramic) in demanding industrial and laboratory equipment. These components are typically machined or fabricated from solid fused quartz or fused silica tubing, often involving precision grinding and polishing to achieve a flawless sealing surface. Yancheng Mingyang Quartz Products Co., Ltd. provides various types of quartz seals, including flange seals, O-rings, bell jar seals, and specialized dome-to-tube interfaces, which are critical for maintaining vacuum integrity, inert gas environments, or high internal pressure at elevated temperatures. The unique advantage of using quartz for sealing is its incredibly low coefficient of thermal expansion (CTE), which minimizes dimensional change during thermal cycling, ensuring the seal remains intact and reliable under the most challenging thermal gradients.

A common application is in creating seals for High-Vacuum and Ultra-High Vacuum (UHV) systems and Diffusion/CVD furnace end caps. Here, the quartz seal provides a leak-tight barrier that is chemically inert to process gases and stable up to 1100∘C or higher. We employ precision CNC machining to grind sealing faces (e.g., knife-edge seals) to exceptionally high flatness and parallelism tolerances, which ensures optimal compression and mating with standard KF, CF, or custom flanges, often using high-temperature graphite or metal gaskets. For direct sealing applications, we offer specialized quartz-to-metal transition seals where a carefully graded glass/ceramic is used to fuse quartz to a metallic flange (like Kovar or stainless steel). This permanent, reliable transition seal is essential where high mechanical strength and absolute vacuum integrity are required, such as in high-power UV lamp construction or specialized vacuum feedthroughs. We customize the profile (e.g., tapered, stepped, concave, or convex) to match the client's mating surface, providing a critical interface component that is safe and reliable at extreme operating limits.

By focusing on precision grinding and material science, we provide essential quartz seals and gaskets that maintain process integrity in environments where conventional materials would fail due to thermal stress or chemical attack.

Specification Parameters

ParameterDetails
Material GradeHigh Purity Fused Quartz or Synthetic Fused Silica
Seal TypeFlange Seals, Knife-Edge Seals, Bell Jar Seals, Gasket Rings, Quartz-to-Metal Transitions
Max Operating TempUp to 1100∘C (Limited by mating gasket/material in system)
Vacuum IntegrityDesigned for High Vacuum (HV) and Ultra-High Vacuum (UHV) systems
Sealing Surface FlatnessPrecision ground to high tolerance (≤5 μm deviation)
Dimensional ToleranceTight CNC tolerances (±0.05 mm on critical dimensions)
Chemical ResistanceInert to most corrosive gases and liquids at high temperature
Custom FeaturesDrilled Holes, Tapered Profiles, Grooves for O-rings or Wire Feedthroughs

The main technical challenge for High-Temperature Quartz Seals and Gaskets is achieving and maintaining the vacuum integrity under high thermal load. The low CTE of quartz (∼0.5×10−6/K) is the property that overcomes this challenge; it ensures that the sealing face does not significantly expand or contract relative to the mating material (e.g., a graphite gasket or a metal flange) during heating and cooling cycles, preventing leaks and seal failure. We control the Sealing Surface Flatness to a very high degree using CNC grinding and lapping to ensure intimate contact with the gasket material, often verifying flatness using a granite reference plate. For UHV applications, the quartz seal is superior because fused silica has a very low outgassing rate compared to polymers or even some ceramics, which helps achieve the extreme low pressures required. The Quartz-to-Metal Transition Seals are achieved by using graded glass layers with a gradually increasing CTE between the low-CTE quartz and the high-CTE metal, creating a stress-free, permanent fusion joint that can be safely cycled thousands of times. We provide precise Dimensional Tolerance on all bolt circles and $\text{OD}$s to ensure drop-in compatibility with standard ISO or ANSI flange systems, minimizing installation time and risk.

Applications

  • Semiconductor Furnace End Caps/Seals: Used to seal the ends of diffusion and CVD process tubes, ensuring a leak-tight, inert atmosphere for wafer processing at high heat.

  • High-Vacuum and UHV Systems: Employed as viewing windows, sample feedthroughs, and structural seals in vacuum chambers due to low outgassing and thermal stability.

  • High-Pressure/High-Temperature Reactors: Serving as robust sealing rings or windows in chemical synthesis and hydrothermal reactors exposed to corrosive chemicals under pressure.

  • Lamp and Laser Envelopes: Quartz-to-metal seals are critical components in high-intensity UV lamps and sealed-tube gas lasers (e.g., CO2​ lasers) that require permanent, high-integrity seals.

  • Optical Fiber Drawing Towers: Used as sealing interfaces within the fusion and drawing zones where high temperatures and controlled environments are essential.

  • Medical and Scientific Instrumentation: Employed as high-purity, chemically resistant seals in specialized analytical instruments.

The reliability provided by a quartz seal is crucial in protecting expensive vacuum equipment and preventing process contamination. For UHV and semiconductor applications, a seal failure can result in catastrophic product loss. Our expertise in fabricating complex geometries, such as tapered interfaces for ground joints, ensures repeatable and reliable sealing. The benefit of the Quartz-to-Metal Seal is that it eliminates the need for a separate, often consumable, high-temperature gasket, creating a permanent, maintenance-free connection between quartz and the metal housing. We work closely with clients to specify the correct sealing profile and purity grade (natural vs. synthetic) based on the temperature profile, pressure differential, and chemical environment of their system, providing a component that is engineered for their specific mission.

Advantages

  • Extreme Thermal Stability: Low CTE ensures the seal maintains integrity under rapid and wide thermal cycling without leaking or fracturing.

  • Superior Vacuum Integrity: Low outgassing rate of fused silica makes the seals ideal for High Vacuum (HV) and Ultra-High Vacuum (UHV) applications.

  • Precision Sealing Surface: CNC grinding achieves high flatness and parallelism, ensuring a reliable, leak-tight seal with mating gaskets and flanges.

  • Chemical Inertness: Impervious to most corrosive gases and cleaning agents used in high-tech processes.

  • Permanent Quartz-to-Metal Options: Fused transition seals provide permanent, high-strength, vacuum-tight interfaces between quartz and metal components.

  • Custom Geometry Fabrication: Ability to manufacture complex sealing profiles (tapered, grooved, knife-edge) to match specialized furnace and reactor designs.

The key advantage is reliability in high-stress environments. Our precision machining and material science expertise ensure that the quartz seal is often the most durable component in the system. We provide full dimensional and material certification, giving clients the confidence to deploy these seals in mission-critical applications where failure is not an option. Our custom fabrication capability means we can solve unique sealing challenges that standard catalogue parts cannot address.

Payment and Shipping

We accept standard payments (T/T, L/C). Due to the custom precision required, custom-machined seals may require a design review fee or a deposit upon order confirmation.

Shipping Protocol for Seals: Protection of the ground sealing surface is paramount.

  • Individual Protection: Each precision seal is individually wrapped in non-abrasive film or mounted in a custom foam carrier to prevent scratching of the sealing faces.

  • Rigid Packaging: Items are secured in reinforced cartons or wooden crates to prevent movement or impact during transit.

  • Documentation: Shipments include dimensional QC reports, and for quartz-to-metal seals, leak test certifications are provided.

Lead times for standard gasket rings are 10−15 working days. Precision CNC-machined flange seals and complex quartz-to-metal transitions require 4−8 weeks for fabrication, grinding, and testing.

Frequently Asked Questions (FAQ)

  • Q: What is a quartz-to-metal seal and why is it used?

  • A: It is a permanent, hermetic (airtight) seal created by fusing quartz to a compatible metal (like Kovar or specialized alloy) using a graded glass layer to mediate the CTE difference. It is used to create robust, maintenance-free electrical or optical feedthroughs into a vacuum or high-pressure chamber.

  • Q: Can a quartz flange seal be reused?

  • A: Yes, quartz seals are highly durable. If the sealing surface is not damaged (scratched or etched), they can be reused multiple times. The corresponding gasket (metal, graphite, or elastomer) must typically be replaced with each cycle.

  • Q: What materials are typically used as gaskets with quartz seals?

  • A: For high temperature/vacuum, Grafoil (pure graphite) gaskets or soft metal gaskets (e.g., OFHC copper) are used. For lower temperatures, Viton or other high-grade elastomers can be used, but the temperature limit will be determined by the elastomer.

  • Q: Do the sealing faces require special cleaning?

  • A: Yes. For UHV and high-purity processes, the quartz sealing surface must be meticulously cleaned with high-purity solvents (IPA or acetone) and should not be touched by bare hands to prevent contamination that could cause leaks or chemical reactions.

From Made-in-China to
Global Smart Manufacturing

Yancheng Mingyang Quartz Products Co., Ltd. is a company specializing in the production of quartz and special glass products. Yancheng Mingyang Quartz Products Co., Ltd. is the production plant of Jinzhou Mingde Quartz Glass Co., Ltd. in Jiangsu, Since its establishment, the company has developed rapidly, introduced advanced technology and production equipment at home and abroad, and continuously improved and improved product quality. Relying on its own advantages, we have developed a variety of products suitable for the market and meet the needs of different customers, and solved many urgent production problems for our customers.

The company's products include quartz glass tubes, double-hole quartz glass tubes, quartz glass rods, quartz sheets, sapphire windows, calcium fluoride glass windows, infrared ultraviolet coatings, high-pressure resistant aluminosilicate glass window panels, quartz glass instruments, high borosilicate glass instruments, quartz crucibles, quartz gold-plated tubes, quartz heaters, quartz infrared heating tubes, far-infrared directional radiation heaters ultraviolet germicidal lamps and other special types of quartz glass products.

Yancheng Mingyang Quartz Products Co., Ltd.
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