Customized High temperature resistance transparent quartz glass tube for heating

Definition of quartz glass tube

Quartz glass tubes are cylindrical vessels made primarily from fused quartz, a material renowned for its exceptional properties. Their most notable characteristic is an extremely high melting point and superior resistance to thermal shock, allowing them to withstand rapid temperature changes without cracking. Additionally, they offer high purity, excellent optical transparency (from UV to IR), and outstanding electrical insulation.

These properties make quartz glass tubes indispensable across various industries. They are commonly used as protective sheaths for thermocouples, liners in high-temperature furnaces, chambers for semiconductor wafer processing, and components in lighting systems (such as halogen and UV lamps). Their chemical inertness also makes them ideal for handling corrosive materials in laboratory and industrial settings.

Manufacturing processes of quartz glass tube

Quartz glass tubes are manufactured through continuous melting and drawing processes. The raw material is fed into a high-temperature furnace, where it is melted. The molten quartz is then drawn over a mandrel to form a continuous tube of a specific diameter and wall thickness. The process requires precise control to ensure dimensional accuracy and to prevent the formation of bubbles and impurities. Subsequent steps may include cutting, fire-polishing the ends to prevent cracking situations, and various machining operations.

Characteristics of quartz glass tube

• Exceptional Thermal Properties

High-Temperature Resistance: Quartz glass tubes have an extremely high softening point and can be used continuously at temperatures up to 1100°C. This makes them ideal for furnaces, diffusion processes, and high-temperature thermocouple protection.

Outstanding Thermal Shock Resistance: They can withstand rapid and extreme temperature changes without fracturing, a property derived from their very low coefficient of thermal expansion.

• Superior Optical Clarity

Quartz glass tubes, especially those made from high-purity fused quartz, offer excellent transmission across a wide spectrum of light. They are highly transparent to ultraviolet (UV), visible, and infrared (IR) light. This makes them perfect for UV lighting (e.g., mercury vapor lamps), semiconductor photolithography, and various optical instruments.

• High Purity and Chemical Stability

Quartz is inherently chemically inert. Quartz glass tubes are highly resistant to most acids, salts, and halogens (like chlorine and bromine) at elevated temperatures. This high purity prevents contamination in sensitive processes such as semiconductor wafer fabrication and pharmaceutical production.

• Good Electrical Insulation

With high electrical resistivity and low dielectric loss, quartz glass tubes are excellent electrical insulators, even at very high temperatures. This is crucial for applications in lighting, laser systems, and high-temperature electrical heating elements.

• Mechanical and Physical Properties

They possess good mechanical strength and rigidity under compressive loads. However, like most glassware, they are brittle and can be susceptible to impact or mechanical abuse if not handled properly.

• High Purity and Chemical Resistance

Inertness: Quartz glass tube is highly resistant to corrosion by most acids, salts, and metals. This chemical inertness ensures product purity in sensitive processes.

Low Thermal Conductivity: It acts as an excellent high-temperature insulator.

Application of quartz glass tube

Quartz glass tubes are critical components in many high-tech and industrial processes due to their unique combination of physical and chemical properties.

• Semiconductor Industry:

In the fabrication of microchips, ultra-pure quartz glass tubes serve as diffusion tubes, oxidation chambers, and furnace liners in wafer processing equipment. Their purity prevents contamination of silicon wafers, while their thermal stability is essential for high-temperature doping and annealing processes.

• Lighting:

Quartz glass tubes are the envelope material of choice for halogen lamps, high-intensity discharge (HID) lamps, and UV sterilization lamps. Their ability to withstand high temperatures and pressure, combined with UV transparency, is crucial for the efficiency and longevity of these light sources.

• Laboratory and Chemical Processing:

Their resistance to thermal shock and corrosive chemicals makes quartz glass tubes ideal for laboratory apparatus such as reactors, condensers, and sample holders. They are used in acid digestion, CVD (Chemical Vapor Deposition) systems, and precision optical experiments.

• Heating Elements:

Quartz tubes are widely used as protective sheaths for metal-sheathed heating elements and as the radiant body for infrared heaters, providing efficient and clean heat transfer.

Common types of quartz glass tube

Transparent Fused Quartz: Standard grade for general high-temperature applications.

Opaque Fused Quartz: Contains numerous small air bubbles, providing better light diffusion and slightly lower thermal conductivity.

Synthetic Fused Silica: Made from chemically synthesized silicon tetrachloride, offering the highest possible purity and UV transmission for critical applications like semiconductor lithography.

Technical specifications of quartz glass tube