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
|
Source: Goodfellow
For more information on this source please visit Goodfellow.