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.
MACOR® contains the following compounds
| Material | Approximate Weight |
|---|---|
| Silicon - SiO2 | 46% |
| Magnesium - MgO | 17% |
| Aluminum - AL2O3 | 16% |
| Potassium - K2O | 10% |
| Boron - B2O3 | 7% |
| Fluorine - F | 4% |
| Property | Units | Aluminium Silicate M-120F |
MACOR® |
|---|---|---|---|
| Colour | Tan to Pink | White | |
| Density | G/CC | 2.3 | 2.52 |
| Porosity | % Water Absorption | 3 | 0 |
| Flexural str. | KPSI | 9 | 13 |
| Compressive str. | KPSI | 40 | 50 |
| Hardness | Knoop | 500 | 250 |
| Thermal cond. | W/M°K W/M°C |
1.3 | 1.46 |
| Coefficient of linear thermal expansion | 25° to 300°C 25° to 1500°C (X10-6) |
3.3 | 9.3 |
| Maximum use temp. | °C | 1150 | 1000 |
| Vacuum atmosphere | °C | - | |
| Dielectric Str. | Volts/Mil V/MMX 103 |
100 | 1000 |
| Volume resistivity | ohm-cm 25° | >1014 | >1016 |
| Dielectric constant | 1 MHZ 25°C 1 KHZ 25°C |
5.3 - |
6.03 |
| Loss factor | 1 MHZ 25°C 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.