Technical glass ceramics picture
 
Home / Products / Technical Glass / ULE Zero expansion glass

ULE®

Zero expansion titania-silicate glass 7972

Special Properties

  • Ultra-low thermal expansion
  • Very high temperature shock resistance
  • High operating temperature
  • Also available at large dimensions

Typical Applications

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

The titania silicate glass ULE® is a zero expansion material. It is made by a flame hydrolysis process. ULE® raw glass materials from CORNING come in large, unshaped glass blocks, so called "boules", which allow the manufacturing of components with almost any shape or dimension. At room temperature the glass material offers a coefficient of thermal expansion very 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 on request. Those grades 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 technology, astronomy, precision mechanical machines, and for lasers and laser-cavities. Also reference length standards for CNC-machines are often made of ULE® glass. But due to its interesting properties of course also for scientific applications the material is used. Components with dimensions of only some millimeters up to several meters can be fabricated from this extraordinary glass material.

ULE® has the excellent optical clarity and chemical resistance which is expected of a glass. Furthermore it provides a very high degree of thermal shock resistance which enables break through technology in optical fiber techniques for medical applications. No measurable hysteresis is exhibited after heavy thermal cycles. When ULE® glass is 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:

 

Request for Quotation

 

Specifications

 

Optical Properties

Show 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 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. In addition, please consider our "Notes on technical specifications"