TECHNICAL DESCRIPTIONMacor® is a white, odorless, porcelain-like (in appearance) material composed of approximately 55% fluorophlogopite mica and 45% borosilicate glass. It contains the following compounds (in weight percent):
Silicon ( Si O2 ) 46% Magnesium ( Mg O ) 17% Aluminum ( Al2O3 ) 16% Potassium ( K2O ) 10% Boron ( B2O3 ) 7% Fluorine ( F ) 4%
GENERAL PROPERTIESMacor® Machinable Glass Ceramic is has a continuous use temperature of 800°C. Its coefficient of thermal expansion readily matches most metals and sealing glasses. It is nonwetting, exhibits zero porosity, and unlike ductile materials, won't deform. It is an excellent insulator at high voltages, various frequencies and high temperatures. And when properly baked out, it won't outgas in vacuum environments. Macor® is WHITE in color.
MACHINING RECOMMENDATIONSMacor® may be machined using standard metal working tools and operations, including lathes, drills, mills, and machining centers. Macor® machining tolerances are surprisingly tight, up to .0005". It can be machined to a surface finish of less than 20 µin. and polished to a smoothness of 0.5 µin.-AA finish.
High speed steel tools may be used, but carbide tools are recommended for longer wear. Water-soluble coolants which are recommended for glass or ceramics should be used, such as Cimstar-40 Pink. No post firing is required after machining. Recommended equipment, feeds and speeds include:
Grinding --- diamond, silicon-carbide or aluminum-oxide grinding wheel
Sawing --- 100 fpm band speed carbide grit, silicon-carbide or diamond wheel
Turning --- 30-50 sfm, .002-.005 ipr, .150 cut depth
Milling --- 20-35 sfm, .002 ipt, .150-.200 cut depth
Drilling --- ¼ dia - 300 rpm, .005 ipr / ½ dia - 250 rpm, .007 ipr / 1 dia - 100 rpm, .010 ipr
SEALING, JOINING AND METALIZINGMacor® MGC can also be joined or sealed - both to itself and to other materials - in a number of ways: metalized 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 metalized using metal inks, or thin film metalized by sputtering.
TYPICAL APPLICATIONS Ultra High Vacuum Environments Constant Vacuum Applications - microwave spacers, headers, windows Aerospace Industry - retaining rings, radiation detectors Nuclear-Related Experiments - reference cubes Welding Nozzles Fixtures, Electrodes, Burner Blocks Medical Equipment
TYPICAL PROPERTIES of MACOR® MGC
|ASTM or UL test||Property||Macor® MGC|
|D570||Water Absorption, 24 hrs (%)||0.01|
|D695||Compressive Strength (psi)||50,000|
|D790||Flexural Strength (psi)||13,600|
|-||Modulus of Elasticity (psi)||9,700,000|
|-||Shear Modulus (psi)||3,700,000|
|D696||Coefficient of Linear Thermal Expansion
(x 10-6 in./in./°F)
|D648||Heat Deflection Temp (°F / °C)
at 264 psi
240 / 116
|D3418||Melting Temperature (°F / °C)||none|
|-||Max Operating Temp (°F / °C)||1832 / 1000|
(x 10-4 cal/cm-sec-°C)
|D149||Dielectric Strength (V/mil) short time, 1/8" thick||1000|
|D150||Dielectric Constant at 1 KHz||6.03|
|D150||Dissipation Factor at 60 Hz||-|
|D257||Volume Resistivity (ohm-cm)at 50% RH||> 1016|
NOTE: The information contained herein are typical values intended for reference and comparison purposes only. They should NOT be used as a basis for design specifications or quality control. Contact us for manufacturers' complete material property datasheets.MACOR is a registered trademark of Corning Incorporated
All values at 73°F (23°C) unless otherwise noted.