SCHOTT 8245

Alternative and trade names
SCHOTT 8245
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Description

For sealing to kovar metal and molybdenum with minimum X-ray absorption, chemically highly resistance and electrically highly insulating.

Properties

General

Density ρ

2.31 g/cm³ at 20 °C

Mechanical

Elastic modulus E

68 GPa at 20 °C

Poisson's ratio ν

0.22 [-] at 20 °C

Thermal

Annealing temperature Tanneal

515 °C

Viscosity 10¹³ dPa.s (ISO 7884-4)

Coefficient of thermal expansion α

5.1E-6 1/K at 20 °C

mean value for 20-300 °C - ISO 7991

Glass transition temperature Tg

505 °C

ISO 7884-8

Softening temperature Tsoftening

720 °C

Viscosity 10⁷·⁶ dPa.s (ISO 7884-3)

Specific electrical resistance temperature Tk

215 °C

For ρ = 10⁸ Ω·cm

Thermal conductivity λ

1.2 W/(m·K) at 90 °C

Working temperature Tworking

1040 °C

Viscosity 10⁴ dPa.s (ISO 7884-2)

Electrical

Dielectric constant, 1MHz εr,1MHz

5.7 [-] at 20 °C

Electrical resistivity ρel

251189 Ω·m at 250 °C

Show chart

Loss tangent, 1MHz tanδ1,MHz

8E-4 [-] at 20 °C

Optical

Refractive index nd

1.49 [-]

at λ=587.6 nm

Stress optical coefficient k

3.8E-6 mm²/N

DIN 52314

Chemical properties

Element

Weight %

Comment

Other

0.01 %

max., Lead, Cadmium, Mercury and Hexavalent Chromium

Technological properties

Application areas

Signal intensifier, detector and (fibre-) optics (Transmitter, X-ray tubes, Video-frequency tubes, Photomultiplier tubes), Sensors, Lasers.

Corrosion properties

Hydrolytic resistance Class HGB3 (ISO 719) - Acid resistance Class S4 (DIN 12116) - Alkali resistance Class A3 (ISO695)

This material data has been provided by Schott Glass Tubing.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.