As an industrial material with high technological content, quartz tubes play a crucial role in modern manufacturing due to their unique physical and chemical properties. This article analyzes the core characteristics and application fields of quartz tubes from a technical perspective.
Fundamentals of Materials Science
Quartz tubes are mainly composed of silicon dioxide (SiO₂), presenting a three-dimensional network structure of silicon-oxygen tetrahedrons. They are classified into fused quartz tubes and synthetic quartz tubes based on manufacturing processes. Synthetic quartz tubes are produced using Chemical Vapor Deposition (CVD) with silicon tetrachloride (SiCl₄) as the raw material, achieving a purity of over 99.99% and controlling impurity content at the ppm level.
Key technical parameters include: a linear thermal expansion coefficient of only 5.5×10⁻⁷/°C, approximately 1/20 that of ordinary glass; a softening point of 1215°C; and hydroxyl (OH) content controllable within the range of 5-300ppm.
Advanced Manufacturing Processes
CVD Process Technology
Chemical Vapor Deposition is the most advanced manufacturing method, with the reaction equation: SiCl₄ + O₂ → SiO₂ + 2Cl₂. Process parameters include a reaction temperature of 1400-1600°C and a deposition rate of 0.5-2μm/min. Quartz tubes produced by this process have a bubble rate of <0.01% and excellent optical uniformity.
Tube Drawing and Forming Technology
Continuous drawing is performed using a multi-zone heating furnace, with temperature control accuracy of ±5°C and outer diameter control accuracy reaching ±0.1mm, ensuring the geometric precision of the product.
Key Technical Performance
- Optical Performance: Transmittance >90% in the UV region (200-400nm), >92% in the visible light region, and a refractive index of 1.4585 (at 589.3nm).
- Thermal Performance: Thermal conductivity of 1.4 W/(m·K), specific heat capacity of 0.67 J/(g·K), and capable of withstanding long-term operating temperatures above 1000°C.
- Mechanical Performance: Tensile strength of 50-70 MPa, compressive strength >1000 MPa, and Young’s modulus of 73 GPa.
High-Tech Application Fields
Semiconductor Manufacturing Processes
Used as reaction chambers in diffusion furnaces and CVD equipment, requiring an inner diameter tolerance of ±0.5mm, surface roughness Ra<0.5μm, and the ability to withstand various corrosive gases and temperature cycles.
Optical Fiber Communication
Applied in the manufacturing of optical fiber preforms, with concentricity requirements <0.5%, ellipticity <1%, and OH content <1ppm, which directly affects the transmission performance of optical fibers.
Precision Analysis
In ICP-MS plasma torch tubes, they operate at temperatures up to 6000-10000K, and provide a chemically inert environment in atomic absorption spectrometers.
Quality Control Technology
ICP-MS is used for ppb-level purity analysis, infrared spectroscopy for hydroxyl content detection, and laser interferometers for geometric accuracy measurement. Stress birefringence testing ensures that the stress level is controlled below 10nm/cm.
Directions for Technological Development
Future development focuses include ultra-high purity technology (metal impurities <10ppb), functional surface treatment, and intelligent manufacturing processes based on artificial intelligence. These technological innovations will further expand the application of quartz tubes in emerging technology fields.
The technological development of quartz tubes represents the perfect combination of materials science and precision manufacturing, providing irreplaceable technical support for modern high-tech industries.