Macor

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MACOR is a glass-ceramic , which with conventional machine tools by machining can be edited ( English machinable ceramic , therefore probably the name). Macor, developed and sold by Corning Incorporated , is a white, porcelain- like material with excellent thermal properties. It is used as an efficient heat and power insulator and is stable up to approx. 1000 ° C. It is free of pores, very little outgases when heated and has a very low thermal expansion. The combination of good processability with common metalworking machines ( milling , turning ) and the thermal properties have made Macor a popular material in many applications.

A number of manufacturers offer competing products ( VITRONIT , ..) with similar composition and properties.

composition

MACOR consists of mica built into a borosilicate glass matrix. The chemical composition is approximately:

properties

MACOR has a density of 2.52 g / cm 3 and a thermal conductivity of 1.46 W / (m · K). Their coefficient of thermal expansion at temperatures from 25 to 300 ° C is only 9.3 × 10 −6  m / (m · K). The processing properties correspond to those of borosilicate glass . Macor is a very good electrical insulator ( ρ > 10 17 Ω · cm) and does not have the creep or flow that is common for many glass-like materials when heated. As a result, it offers very good dimensional stability and low manufacturing tolerances. It is resistant to ionizing radiation and can be polished to a high gloss.

safety

Macor is non-toxic and there are no harmful effects on health. The special thermal stability make it safe for most applications. However, the dust produced when processing Macor can be irritating and should not be inhaled.

Applications

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

Individual evidence

  1. ↑ Glass Ceramic - MACOR® Machinable Glass Ceramic . Corning website. Retrieved August 10, 2012.
  2. ↑ Machinable glass ceramic VITRONIT manufacturer website , accessed August 27, 2015