Technical Ceramics


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 - K2 10%
Boron - B2O3  7%
Fluorine - F  4%



Property Units Aluminium Silicate
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
1.3 1.46
Coefficient of linear thermal expansion 25° to 300°C
25° to 1500°C
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
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.