Q5: What is the temperature resistance limit of quartz glass?

Q5: What is the temperature resistance limit of quartz glass?

Q5: What is the temperature resistance limit of quartz glass?

A: 

Quartz glass has an ultra-low linear expansion coefficient of only 5.5×10⁻⁷/°C, giving it excellent anti-quenching ability. Certified products can resist temperature alternations with a 1000°C temperature difference without cracking or deformation. A typical test: heating quartz sheet to 1100°C then quenching in room-temperature water will not break the product, an advantage ordinary heat-resistant glass cannot match.

4. How Purity & Hydroxyl Affect Temperature Resistance

Hydroxyl (-OH) impurities are the key factor that changes high-temperature performance:
  • High OH quartz (>800ppm): Long-term temperature drops 30–50°C, prone to devitrification above 1100°C
  • Medium OH electric-melt quartz (100–300ppm): Balanced cost and heat resistance, standard 1100°C long-term limit
  • Ultra-low OH synthetic quartz (≤10ppm): Stable at 1200°C long-term, little performance loss after hundreds of thermal cycles Excess metal impurities like sodium and aluminum will also accelerate surface crystallization at high heat and lower the usable temperature ceiling.

5. JGS Grade Temperature Parameter Reference

  • JGS1 Far UV Synthetic Quartz: Long-term 1150–1200°C, short peak 1400°C, for UV lithography & semiconductor high-temp windows
  • JGS2 UV-VIS Synthetic Quartz: Long-term 1100–1150°C, short peak 1350°C, for lab furnace sight glass & precision thermal instruments
  • JGS3 Infrared Electric-Melt Quartz: Long-term 1100°C, short peak 1300°C, for infrared heating equipment

6. Practical Usage Tips

  1. Vacuum working environment: Reduce long-term allowable temperature by 50–100°C to avoid silica volatilization
  2. Avoid direct contact with molten alkali metal above 900°C, chemical corrosion will shorten service life
  3. Slow cooling (≤5°C/min) after high-temperature operation to prevent thermal shock cracks
To sum up, the universal industrial temperature resistance standard of quartz glass is 1100–1200°C for long continuous work, 1300°C for short transient heating. The actual usable temperature is adjusted by material grade, purity, atmosphere and thermal cycle frequency.