Macor

Macor is a glass ceramic which can be machined with conventional machine tools (English machinable ceramic, hence probably the name). Macor, developed and sold by Corning Incorporated, is a white, porcelain - like material having excellent thermal properties. It is used as an efficient heat and electricity insulator and is up to about 1000 ° C stable. It is non-porous, hospitable if strongly heated from very little and has a very low thermal expansion. The combination of good processability with conventional metal working machines (eg, milling machine, lathe ) and thermal properties have made Macor a popular material in many applications.

Composition

Macor is composed of mica installed in a borosilicate glass matrix. The chemical composition is approximately:

• 46% silica (SiO2)
• 17% magnesium oxide (MgO)
• 16 % of alumina ( Al2O3)
• 10% potassium ( K2O)
• 7% boron ( B2O3)
• 4% fluorine (F)

Properties

MACOR has a density of 2.52 g/cm3 and a thermal conductivity of 1.46 W / (m · K). Its coefficient of thermal expansion at temperatures of 25 to 300 ° C is only 9.3 x 10-6 m / (m · K). The machining characteristics similar to those of borosilicate glass. Macor is a very good electrical insulator and does not have the usual for many glassy materials creep or flow when heated. It thus offers a very good dimensional stability and low manufacturing tolerances. It is resistant to radiation and can be polished to a high gloss.

Security

Macor is non-toxic and there are no health -damaging effects unit. The special thermal stability make it safe for most applications. However, the resulting in the processing of Macor dust may be irritating and should not be inhaled.

Applications

Macor is used in nuclear engineering, aerospace, medical, and research. It is often used in high temperature or ( ultrahigh ) vacuum environments where outgassing and / or dimensional stability are important.