Zerodur vs ULE

ULE and ZERODUR, zero-expansion glasses, play a key role in various industries including space exploration and high-tech manufacturing. They are interchangeable in some applications like astronomy and space reflectors. Corning's ULE and SCHOTT's ZERODUR are both essential materials to consider.

 

Zero expansion materials are materials that exhibit minimal or no expansion or contraction when subjected to changes in temperature. Some common types of zero expansion materials include ceramics, glasses, and certain alloys.

The main uses of zero expansion materials are in applications where dimensional stability is critical. This includes precision machining, semiconductor manufacturing, aerospace, and defense industries. In addition, zero expansion materials are used in high-precision optical equipment where changes in temperature can affect the accuracy of the system.Taking Zero Expansion Glass as an example, one of the more representative ones is ULE of CORNING (USA) and the other one is ZERODUR of SCHOTT (Germany), which are widely used in the above mentioned fields at present.

 

Component structure

- ULE that is, ultra-low expansion coefficient quartz glass, is the United States CORNING company developed a kind of modified quartz glass doped with 7.5% TiO2, which is produced by SiCl4 and TiCl4 mixture of gases through the flame hydrolysis technology. The quartz glass has low density, strong polishability, and can realize light weight by welding technology, which is a more ideal material for mirror body.

- Zerodur is a microcrystalline glass with an approximate zero coefficient of expansion produced by Schott in Germany. Zerodur is a microcrystalline glass produced by Schott in Germany. It is made by heat treating LiO2-Al2O3-SiO2 system glass to precipitate a large number of tiny crystalline particles with negative coefficients of expansion, thus making the overall coefficient of expansion of the microcrystalline glass reach or be close to zero.

 

Functional Characteristics

- ULE is a fused silica material that contains very low levels of impurities such as metal ions and gas bubbles, which results in highly uniform physical and chemical properties. It also has very low birefringence and excellent transmittance in the infrared range, which makes it ideal for high power laser systems, astronomical instruments and semiconductor fabrication equipment.

- Zerodur glass has very low internal stresses, low thermal conductivity and high dimensional stability, maintaining its shape and precision even under extreme temperature and environmental conditions. It is often used in space-based instruments, x-ray telescopes and other high-performance optical applications.

 

Pros and Cons

- ULE glass has very high thermal stability (up to 500°C) and a very low coefficient of thermal expansion, which makes it ideal for applications requiring high precision and accuracy, such as optical mirrors, lenses and substrates. However, it can be brittle and difficult to mold or process.

- Zerodur glass has a lower coefficient of thermal expansion than ULE glass (~0 ppm/K), which makes it very stable and resistant to thermal shock and deformation. It also has excellent mechanical strength and hardness, which makes it suitable for use in large telescopes and other applications requiring high stiffness and durability.

Comparatively speaking, Zerodur glass has better cutting characteristics than ULE, which is more brittle, but ULE has better soldering (melting) characteristics. Zerodur is at a disadvantage when it comes to temperature adaptability and long-term stability.

 

Can the two replace each other?

Zerodur and ULE are interchangeable in the field of astronomy, and in the field of aerospace mirrors. The main mirror of the Hubble Space Telescope is made of ULE glass by welding. The European Extremely Large Telescope (ELT), as the world's largest optical telescope, with a main mirror diameter of 39.3 meters, requires a material that can maintain stability under extreme temperature changes. zerodur microcrystalline glass was chosen as the material for the ELT's main mirror due to its extremely low coefficient of thermal expansion, ensuring that the telescope is able to provide a clear image when observing.

In summary, Corning's ULE glass and SCHOTT's Zerodur glass are two of the most commonly used high-performance glasses in the world of advanced optics and engineering.ULE glass is known for its excellent uniformity, ease of fabrication, and low coefficient of thermal expansion, while Zerodur glass is known for its superior mechanical and thermal properties, making it ideal for applications requiring high strength, durability, and resistance to thermal shock. Regardless of their specific pros and cons, both types of glass have proven to be essential materials for a wide range of industries, from space exploration to high-tech manufacturing.

 

MG Optics is a professional optical lens manufacturer with many experienced technical engineers who can select the most suitable optical material for your optical system. Not only can we process high-precision ULE and ZERODUR lenses, but we also have fused silica glass (JGS1\JGS2\JGS3) for you to choose from at a super cost-effective price, so send us your drawings and get a quote!