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.