Glass-ceramic with an Ultra-Low Thermal Expansion Coefficient and developed by High Homogeneity melting and Precise Crystallization. 

Key Properties of CLEARCERAM®-Z

Ultra-Low Expansion Glass

  • Shows almost Zero Thermal Expansion over a wide temperature range & offers superior thermal shock resistance
  • CCZ-Regular offers lower thermal expansion across a wide temperature range
  • CCZ-HS offers lower thermal expansion near room temperature.
  • Superior Mechanical Properties – The crystal grain structure of prevents the propagation of microscopic cracks that can be caused in between machining processes. This allows CCZ to be processed into various shapes with high accuracy and elevated yield rates. CLEARCERAM®-Z is comprised of approximately 70% ceramic material, which makes the mechanical characteristics superior to regular amorphous glass when comparing properties such as Young’s Modulus, Rigidity, Bending Strength, and Knoop Hardness.
  • Excellent chemical resistance, durability, and stability in various cleaning and thin-film coating processes as the composition does not contain Na, K, B, F, or Pb.


CLEARCERAM®-Z is used for semiconductor stepper components, liquid crystal stepper components, optical flats, spacers, windows, interferometer components, laser refraction mirrors and suspensions, astronomical telescope mirrors, block gauges, long precision scales, optical pedestal platforms, and pedestals for precision equipment. This material is an ideal alternate to quartz glass, ceramics, or low thermal expansion alloys. Please contact us for additional details about CLEARCERAM®-Z- Ultra Low Expansion Glass.



‘Laser Focus World – December 2015’

At the heart of the TMT are the 492 hexagonal mirrors that make up the telescope’s primary mirror. Ohara Inc. is supplying the 574 M1 segment mirror blanks needed for the telescope (Including spares) and has produced more than 100 mirror blanks already. Made of Ohara’s CLEARCERAM®-Z ultra-low expansion glass ceramic, each blank is 1.5 m in diameter and about 50 mm thick, according to Brion Hoffman, president of Ohara Corp.

(Courtesy of Laser Focus World and the TMT).


E6 Low Expansion Glass - OC’s Work with The University of Arizona

Ohara manufactures E6 Low Expansion Glass specifically for University of Arizona’s mirror projects. E6 is used in the primary mirrors for U of A’s Giant Magellan Telescope. The Giant Magellan Telescope (GMT) is currently under construction at the Las Campanas Observatory in Chile. The GMT is a segmented mirror telescope that will utilize seven monolithic lightweight mirrors (the world’s largest) made of Ohara E6 low expansion glass. Six off-axis 8.4 meter in diameter, or 27-foot, mirror segments surround a central on-axis mirror segment, forming a single optical surface 24.5 meters, or 80 feet, in diameter.