MACOR®
Machinable Glass Ceramic (MGC)
Special Properties of MACOR®
- Machinable with HSS metalworking tools
- Highly temperature-resistant
- Non-porous
- Dimensionally stable
- Does not outgas
- Odorless, opaque, white material
- Excellent electrical insulator
- The coefficient of thermal expansion is close to that of many metals and sealing glasses
- Available as semifinished parts
- Radiation resistant
- No post-firing required
Typical Applications
- High-precision workpieces
- Contact holders, sockets, bushings, and feedthroughs
- Aerospace applications
- Equipment for field ion microscopes
- Ultra-high vacuum and continuous vacuum applications
- Medical devices
- Laser cavity components
- Insulators for electronic connectors
- Semiconductors and electronics
- Nuclear research
- Welding nozzles
- Bushing tubes
- Mounting brackets
- Laser alignment components
Related Ceramic Materials
What is MACOR®?
MACOR® is a machinable glass ceramic (MGC) made by CORNING. It is a white, odorless, and opaque material comprising 55% MIKA and 45% borosilicate glass. The high-performance 
material has ideal properties for a wide range of industrial applications. MACOR® allows the design and precise manufacturing of complex-shaped parts with tight tolerances. It can be CNC-machined with conventional HSS tools commonly used for machining metal. No expensive special equipment, machinery, or diamond tools are required to process MACOR®.
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Figure: A finished part with tight tolerances made of MACOR® MGC |
MACOR® is a Material with Special Properties
MACOR® can be used at temperatures of up to 800 °C for long periods and withstands even up to 1000 °C without load. It has zero porosity and is non-wetting. MACOR® does not deform or outgas. It can be used in vacuum environments and does not require post-firing like other ceramics do. Moreover, it is an excellent insulator for high voltages at various frequencies, as it provides low conductivity. MACOR® MGC sets an industrial standard for machinable ceramics. It is ideal for various aerospace, medical, and semiconductor applications.
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MACOR® allows the design of such tiny and intricate parts with high precision. |
To get a quote for MACOR® glass ceramic material or a finished part with custom shape and dimensions according to your drawing, please click the button below:
Specifications, Properties,
and Raw Materials
Semifinished MACOR® materials
We stock MACOR® sheets, rods, and bars which allows short lead times. These are the starting points for complex-shaped parts. Please see below for all available stock dimensions:
| Rods | |
|---|---|
| Rod diameter (mm) |
Lengths (mm) |
| 3 | 4 | 5 | 6 | 8 | 12.5 | 70 |
| 19 | 25 | 30 | 38 | 50 | 75 | 150 | 300 |
| Get a quote for a MACOR rod | |
| Bars | |
|---|---|
| Size (mm x mm) |
Lengths (mm) |
| 12.5 × 12.5 | 75 | 150 | 300 |
| 19 × 19 | |
| 25 × 25 | |
| 30 × 30 | |
| 50 × 50 | |
| Get a quote for a MACOR bar | |
| Sheets | |
|---|---|
| Size (mm x mm) |
Thicknesses (mm) |
| 75 × 75 | 12.5 | 19 | 25 | 30 | 50 |
| 150 × 150 | |
| 300 × 300 | |
| Get a quote for a MACOR sheet | |
The materials above are typically available in one week or less. Larger dimensions may take a little longer.
MACOR® MGC Machining Guidelines
- MACOR® machining recommendations
(separate web page)
Density
- 2.52 g/cm3
Coefficient of Thermal Expansion per °C
- 74 × 10-7 (-200–25 °C)
- 93 × 10-7 (25–300 °C)
- 114 × 10-7 (25–600 °C)
- 126 × 10-7 (25–800 °C)
Thermal Characteristics
- Continuous operating temperature: 800 °C
- Max. operating temperature: 1000 °C (no load)
- Thermal Diffusivity: (25 °C): 7.3 × 10-7 m2/s
- Thermal Conductivity: (25 °C): 1.46 W/m°C
- Specific Heat (25 °C): 0.79 KJ / kg°C
Mechanical Characteristics
- Porosity: 0%
- Young's Modulus: (25 °C): 66.9 GPa
- Poisson's Ratio: 0.29
- Shear Modulus: (25 °C): 25.5 GPa
- Knoop Hardness: (100 g): 250
- Modulus of Rupture: (25 °C): 94 MPa
- Compressive Strength: 345 MPa
- Fracture Toughness: 1.53 MPa m0,5
Electrical Characteristics
- Dielectric Constant: (25 °C): 6.03 (1 kHz)
- Dielectric Loss Tangent: (25 °C): 4.7 x 10-3 (1 kHz)
- Dielectric Strength: (25 °C): 40 kV / mm
(at 0.254 mm thickness) - Volume Resistivity: >1016 Ω-cm
Composition of MACOR® Glass Ceramic
| Substance | approximate weight percentage |
|---|---|
| Silicon oxide (SiO2) | 46 |
| Magnesium oxide (MgO) | 17 |
| Alumina (Al2O3) | 16 |
| Potassium oxide (K2O) | 10 |
| Boron oxide (B2O3) | 7 |
| Fluorine (F) | 4 |
Chemical Properties
| Medium | pH | Time (h) |
Temp. (°C) |
Weight loss (mg/cm2) |
|---|---|---|---|---|
| 5% HCL | 0.1 | 24 h | 95 °C | Approx. 100 |
| 0.002 N HNO3 | 2.8 | 24 h | 95 °C | Approx. 0.6 |
| 0.1 N NaHCO3 | 8.4 | 24 h | 95 °C | Approx. 0.3 |
| 0.02 N Na2CO3 | 10.9 | 6 h | 95 °C | Approx. 0.1 |
| 5% NaOH | 13.2 | 6 h | 95 °C | Approx. 10 |
| H2O (water) | 7.6 | 24 h | 95 °C | Approx. 0.01 |
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Precise workpieces made of original MACOR® glass ceramic material. |
All data and specifications given are average guide values and are not guaranteed. Moreover, please consider the “Notes on Specifications”.
© 1994 – 2025 Präzisions Glas & Optik GmbH
Last update: March 19, 2025