Machineable Glass Ceramic - SiO2 46/Al2O3 16/ MgO 17/K2O 10/B2O3 7

This Machineable Ceramic is a white ceramic which can be machined with ordinary steel or carbide tools. It has been used extensively in the Space Shuttle Orbiter.

It can be used continuously up to 800 °C and is a good electrical and thermal insulator. Outgassing in ultra-high vacuum environments can be eliminated, if degassed before use.

MACOR® is non-wetting and can be bonded to itself as well as to various metals, if the MACOR® surfaces are first metallised.

Key Properties

The key properties of MACOR® are tabulated below.

Table 1. Key properties

Chemical Resistance
Acids - concentrated Poor
Acids - dilute Fair
Alkalis Fair
Electrical Properties
Dielectric constant 5.9
Dielectric strength ( kV.mm-1 ) 40
Volume resistivity ( Ohm.cm ) >1014 @ 25 °C
Mechanical Properties
Compressive strength ( MPa ) 345
Hardness - Vickers ( kgf.mm-2 ) 400
Tensile modulus ( GPa ) 67
Physical Properties
Apparent porosity ( % ) 0
Density ( g.cm-3 ) 2.52
Thermal Properties
Coefficient of thermal expansion ( x10-6 K-1 ) 13 @ 20-1000 °C
Specific heat ( J.K-1.kg-1 ) 790 @ 25 °C
Thermal conductivity ( W.m-1.K-1 ) 1.5 @ 20 °C
Upper continuous use temperature ( °C )

800-1000

 

About Goodfellow

Goodfellow supplies metals, ceramics and other materials to meet the research, development and specialist production requirements of science and industry worldwide.

The Goodfellow group consists of four companies. The main administration, research laboratories and workshops are located at the Company's headquarters in Cambridge, England. The subsidiary offices in America, France and Germany provide an additional service.

This information has been sourced, reviewed and adapted from materials provided by Goodfellow.

For more information on this source, please visit Goodfellow.

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