Technical Ceramics
MACOR®
MACOR® machinable glass ceramic (MGC) offers a cost effective ceramic solution for myriad applications. If you require a high performance technical ceramic that is capable in high temperatures, features electrical resistivity and zero porosity, MACOR® is an appropriate solution.
The easy working of MACOR® machinable glass ceramic into complicated shapes with extremely tight tolerances means that it can be adapted to a wide variety of applications, in a short space of time. Rapidity of fabrication is further ensured with the removal of a post firing requirement.
The effect of this fast fabrication is a technical ceramic solution that performs excellently in challenging environments and can lead to considerable cost reduction for the manufacture of final products.
Advantages of MACOR®
- MACOR® can be machined with ordinary metal working tools
- No need for post firing – meaning fast turnaround
- Tight tolerances – up to .0005”
- Continued use at 800°C and a peak temperature of 1000°C
- No outgasing and zero porosity makes MACOR® clean
- Reduced time between design and eventual use reduces costs
MACOR® Composition
MACOR® machinable glass ceramic is a white, odourless, porcelain-like (in appearance) material composed of approximately 55% fluorophlogopite mica and 45% borosilicate glass. It has no known toxic effects; however, the dust created in machining can be an irritant. This irritation can be avoided by good housekeeping and appropriate machining techniques.
|
Material |
Approximate Weight |
|---|---|
|
Silicon - SiO2 |
46% |
|
Magnesium - MgO |
17% |
|
Aluminum - AL2O3 |
16% |
|
Potassium - K2O |
10% |
|
Boron - B2O3 |
7% |
|
Fluorine - F |
4% |
|
Property |
Unit |
Aluminium Silicate |
MACOR® |
|---|---|---|---|
|
Colour |
Tan to pink |
White |
|
|
Density |
Mg/m3 |
2.3 |
2.52 |
|
Porosity |
% |
2 - 3 (can be made impervious to water) % nominal |
0 (fully dense) % nominal |
|
Flexural Strength |
MPa |
64 |
89 |
|
Young’s Modulus |
GPa |
55.4 |
68 |
|
Compressive Strength |
MPa |
275 |
345 |
|
Knoop Hardness |
kg/mm2 |
250 |
|
|
Thermal Conductivity |
W/m.K |
1.26 |
1.46 |
|
Thermal Expansion Coefficient |
25° to 300°C, (x10-6) |
3.3 |
9.3 |
|
25° to 1500°C, (x10-6) |
3.3 |
9.3 |
|
|
Maximum no-load Temperature |
°C |
1150 |
1000 |
|
Dielectric Strength |
dc kV/mm |
3.9 |
39.4 |
|
Volume Resistivity |
@25° |
>1014 |
>1014 |
|
Dielectric Constant |
1 KHZ @25°C |
5.3 |
6.03 |
|
Loss Factor |
1 KHZ @25°C |
0.053 |
0.0047 |
Machining MACOR®
Machining tolerances are surprisingly tight, up to .0005". It can be machined to a surface finish of less that 20µin. and polished to a smoothness of 0.5µin.-Ra. Configurations are limited only by available equipment and the experience of the machinist.
Sealing, Joining and Metallising MACOR®
MACOR® MGC can also be joined or sealed - both to itself and to other materials - in a number of ways; metallised parts can be soldered together and brazing has proven an effective method of joining the material to various metals; epoxy produces a strong joint, and sealing glass creates a vacuum tight seal. Even a straightforward mechanical joint is possible. It can be thick film metallised using metal inks, or thin film metallised by sputtering.