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MACOR® Machinable Glass Ceramic

High-Tech MGC material

Special Properties

  • MACOR® can be processed with conventional metal working tools, no glass processing machines required
  • Available as semi-finished rod, bar, and sheet materials
  • Odorless, opaque white material
  • MACOR® is a machinable glass ceramic
  • High temperature resistance
  • Non-porous
  • Dimensionally stable
  • Not outgassing
  • Sealing by using fusing glass possible
  • Good insulator

Typical Applications

  • Flight and aerospace industry
  • Substrates for field ion microscopes
  • Ultra high & continuous vacuum applications
  • Medical equipment
  • Electrical contacting holders
  • Laser cavitiy components
  • Welding nozzles
  • Bushing tubes
  • Mounting brackets
  • Laser adjustment components
  • High precision workpieces
Finished glass ceramic part made of MACOR®
nullspacer Fig.: Finished industrial component design machined from MACOR® glass ceramic.

MACOR®, an extraordinary material machinable
almost like metal

MACOR® machinable glass ceramic from CORNING is a white appearing, odorless, opaque material. It is composed of a 55% share of MIKA and a 45% share of borosilicate glass. The detailed composition is shown on the right. The advanced high performanceSmall machined parts made of MACOR® glass ceramic from CORNING glass ceramic, offers exceptional properties for a broad range of applications and workpiece designs in industries. MACOR allows a rapid production of complex shapes and precise workpieces with tight tolerances. The CNC-machining of MACOR material can be done with normal HSS tooling from metal processing. Expensive glass processing equipment is not necessary to machine this extraordinary glass ceramic. How exactly MACOR® should best be handled, you can learn in our MACOR® processing instructions.


MACOR®, a high-tech glass ceramic that goes to the limit

The possible long term use at temperatures of 800°C and an allowed peak temperature of up to 1.000°C of MACOR, enables a wide variety of interesting sophisticated applications in industries. Corning's unique glass ceramic has zero porosity and is non-wetting. MACOR® glass ceramic does not deform or outgas, which allows the use in vacuum environments. The ceramic material is an excellent insulator at high voltages and various frequencies even at a high operating temperature. MACOR sets an industrial standard for machinable glass ceramics, that can hardly be outperformed by other glass ceramic materials. Hence, MACOR is often used for high tech applications in aerospace, medical, semiconductor technology and for other demanding applications.


Semi-finished materials to finished workpieces

MACOR glass ceramic raw materials are always available in form of sheets, square bars and round rods from stock or at very short lead times. These semi-finished parts can be machined to extremely complicated shapes.

Components of MACOR® glass ceramic nullspacer You are welcome to request a quotation for a custom finished work piece made of original MACOR® glass ceramic or for our semi-finished MACOR® rods, bars or sheets. Please follow this link to send us your enquiry.

To request a quote of any semi-finished standard MACOR® rod, bar or sheet glass ceramic materials or a finished MACOR® workpiece with individual shape and dimensions, please click the button below:

Request for Quotation

Specifications & Properties



  • 2,52 g/cm3

Coefficient of Thermal Expansion

  • 74 x 10-7 / °C (-200 - 25°C)
  • 93 x 10-7 / °C (25 - 300°C)
  • 114 x 10-7 / °C (25 - 600°C)
  • 126 x 10-7 / °C (25 - 800°C)

Thermal Characteristics

  • Continuous operating temp. : 800°C
  • Max. operating temperature : 1.000°C (no load)
  • Thermal Diffusivity (25°C) : 7,3 x 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 (100g) : 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 0,254mm thickness)
  • Volume Resistivity : >1016 Ω-cm
Very small work pieces of MACOR® glass ceramic nullspacer MACOR® machinable glass ceramic materials from Corning even allow the design of very small and complex parts that require to be machined with high precision. If you have any technical question, please just contact us.


Composition of MACOR Glass Ceramic

Substance approximate weight
Silicon Oxide (SiO2) 46%
Magnesium Oxide (MgO) 17%
Alumina (Al2O3) 16%
Potassium oxide (K2O) 10%
Boron oxide (B2O3) 7%
Fluorine (F) 4%

Chemical Properties





Weight loss

5% HCL
ca. 100
0,002 N HNO3
ca. 0,6
0,1 N NaHCO3
ca. 0,3
0,02 N Na2CO3
ca. 0,1
5% NaOH
ca. 10
H2O (water)
ca. 0,01

Semi-Finished Standard Rods, Bars & Sheets
of MACOR® Glass Ceramic


Rod Diameter Rod lengths
3mm 70mm
4mm 70mm
6mm 70mm
8mm 70mm
12,5mm 70mm
19mm 75mm, 150mm, 300mm
25mm 75mm, 150mm, 300mm
30mm 75mm, 150mm, 300mm
38mm 75mm, 150mm, 300mm
50mm 75mm, 150mm, 300mm


Bar Dimension Bar lengths
12,5mm x 12,5mm 75mm, 150mm, 300mm
19mm x 19mm 75mm, 150mm, 300mm
25mm x 25mm 75mm, 150mm, 300mm
30mm x 30mm 75mm, 150mm, 300mm
50mm x 50mm 75mm, 150mm, 300mm

MACOR® Sheets

Sheet sizes
(length x width)

Sheet thicknesses
75mm x 75mm 12,5mm, 19mm, 25mm, 30mm, 50mm
150mm x 150mm 12,5mm, 19mm, 25mm, 30mm, 50mm
300mm x 300mm 12,5mm, 19mm, 25mm, 30mm, 50mm

The typical lead time for the standard MACOR® glass ceramic rods, bars and sheets listed above, is approximately 1 week or less. Only for larger rod, bar and sheet materials, the lead time can be longer. Please send us your request.

Machining guidelines for MACOR® Glass Ceramic

All given details and specifications given here are mean reference values and are not guaranteed. In addition, please consider our "Notes on technical specifications"