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Home / Products / Technical Glass / ULE 7972 Zero Expansion Glass

ULE®

Zero expansion titania-silicate glass 7972

Special Properties

  • Ultra-low thermal expansion
  • Very high temperature shock resistance
  • High operating temperature
  • Available at large dimensions
  • Non-crystalline, amorphous glass (no ceramic)

Typical Applications

  • Ultra-low expansion glass substrates
  • Length standards
  • Lightweight honeycomb mirror mounts
  • Glass scales for CNC machines
  • Solid and lightweight mirror blanks
  • Astronomical telescopes
  • Precision measurement technology
  • Satellite applications in space
  • Laser cavities
  • Precision gyroscopes

Related products

  • ZERODUR® (Zero expansion transparent glass ceramic)

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ULE® titania-silicate glass is a zero expansion material made by a flame hydrolysis process. The amorphous ULE® raw glass materials from CORNING come in large and unshaped glass-blocks, the so-called "boules" which allow the manufacturing of components with almost any shape or dimension. At room temperature, the glass material has a coefficient of thermal expansion close to zero.

By its ultra-low length expansion, ULE® guarantees dimensional stability even under thermally unstable conditions. The homogeneity of the thermal expansion of standard Grade ULE® glass within each boule is typically less than 15 ppb/°C radially and axially. Even lower expansion-grades, as well as detailed information about these material qualities are available on request. Those materials can offer an even higher homogeneity of the coefficient of thermal expansion. The CTE of ULE® glass is measured by a non-destructive ultrasonic test method.

ULE® material is used for various applications in space, astronomy. It is also used in precision mechanical machines, and in lasers and laser cavities. Besides, reference length standards for CNC-machines are often made of ULE® glass. Due to the exciting properties ULE® material is as well used for many scientific applications. Components with dimensions of only some millimeters up to several meters can be fabricated from this unique glass material.

ULE® has the excellent optical clarity and chemical resistance which is expected from a glass. Furthermore, it provides a very high degree of thermal shock resistance which enables breakthrough technology in optical fiber techniques for medical applications. No measurable hysteresis is exhibited after heavy thermal cycles. When ULE® materials are heated to 350 °C and then quenched with water, there is no residual detectable figure change.

To request a quotation for your component or optics made of original CORNING ULE® ultra-low expansion glass with individual dimensions, please click the button below:

 

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Specifications


Optical Properties

Show the transmission of ULE® low expansion glass

  • Refractive Index (nominal CTE material):
    • nF = 1,4892 (486 nm)
      nD = 1,4828 (589 nm)
      nC = 1,4801 (656 nm)
  • Abbe number: vd= 53,1
  • Stress optical coefficient: 4,15 (nm/cm)/(kg/cm2)
  • dn/dt:
    • 10,68 x 10-6/°C (20 - 40 °C)
    • 11,24 x 10-6/°C (40 - 60 °C)

Mechanical properties

  • Density (ρ): 2,21 g/cm3 (25 °C)
  • Elastic Modulus (E): 67,6 GPa
  • Bulk Modulus (K): 34,1 GPa
  • Shear Modulus (G): 29,0 GPa
  • Specific stiffness (E/ρ): 3,12 x 106 m
  • Ultimate Tensile Stress (MOR): 49,8 MPa
  • Knoop Hardness: 460 kg/mm2 (200 g load)
  • Poisson's Ratio (v): 0,17

Thermal Properties

  • Mean linear coefficient of thermal expansion (α):
    0 ± 30 x 10-9/K (5 - 35 °C ; 95% confidence level)
  • Show the typical curve of thermal expansion
  • Softening Point: 1490 °C (estimated)
  • Annealing Point: 1000 °C
  • Strain Point: 890 °C
  • Thermal conductivity (K): 1,31 W/(m x °C)
  • Thermal diffusivity (D): 0,079 cm2/s
  • Mean specific heat (Cp): 767 J/(kg x °C)

Standard Grade material specifications:

  • Maximum CTE variation: 15 ppb/°C (Radial & Axial)
  • Birefringence: 20 nm/cm
  • Inclusion chart on request
  • Specifications for Premium Grade, Mirror Grade and Tooling Grade material quality available on request

Chemical Properties

Solution
(at 95 °C)

Duration of Test
(Hours)

Weight Loss
(mg/cm-2)

5% HCl
24
< 0,01
5% NaOH
6
0,90
0,02N Na2CO3
6
0,02
5% H2SO4
24
< 0,01
H2O
24
< 0,01

Electrical Properties

  • Dielectric Constant : 3,99 (100 Hz ; 25 °C)
  • Loss Factor : 0,00005 (100 Hz ; 25 °C)
  • DC-volume resistivity: 1011,6 Ω x cm

Flatness

Surface Quality

 

All given details and specifications are mean reference values and are not guaranteed. Also, please consider our "Notes on technical specifications".

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