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Macor is the trademark for a machinable glass-ceramic developed and sold by Corning Inc. It is a white material that looks somewhat like porcelain. Macor is a good thermal insulator and is stable up to temperatures of 1000 °C, with very little thermal expansion or outgassing. It can be machined using standard metalworking tools.[1]
Composition
editMacor is made up of fluorphlogopite mica in a borosilicate glass matrix. Its composition is roughly: 46% silica (SiO2), 17% magnesium oxide (MgO), 16% aluminium oxide (Al2O3), 10% potassium oxide (K2O), 7% boron trioxide (B2O3), 4% fluorine (F).[2]
Properties
editMacor has a density of 2.52 g/cm3,[3] a Young's modulus of 66.9 GPa at 25 °C,[3] a specific stiffness of 26.55×106 m2s−2, a Poisson’s Ratio of 0.29[3] and a thermal conductivity of 1.46 W/(m·K).[3] It has a low-temperature (25 to 300 °C) thermal expansion of 9.3×10−6 K−1.[3] Its compressive strength is 50×103 lb/in2 (~350 MPa).[3] Nominal engineering properties are comparable to borosilicate glass.[4]
Extremely machinable, Macor offers tight-tolerance capabilities, allowing complicated shape design (optimal performances up to
±0.013 mm for dimensions, < 0.5
Macor comes in a standard size maxi slab (about 36 cm × 36 cm × 6cm).[5] Components, bars, rods and plates can be machined within the size of this slab (hand tools can be used).
Applications
editMacor is used in the following applications:
- Constant and ultra-high vacuum environments
- Laser technology
- Semiconductor / electronic
- Aerospace / space
- Medical/ laboratory equipment
- Fixtures
- Chemical
- Automobile
- Military
- Nuclear
Safety
editThere are no major safety concerns or toxic effects associated with Macor. The dust created when machining it can be an irritant, and inhalation should be avoided.[6]
Machining guidelines
editKey factors for successful machining are proper machining speeds and coolant. Macor can be machined with high-speed steel tools, but carbide tools are recommended for longer wear. Best results achieved by using a water-soluble coolant (such as Cimstar 40 – Pink) especially formulated for cutting and grinding glass or ceramics. Note: No post-firing is required after machining.
References
edit- ^ "Macor Machinable Glass".
- ^ "MACOR Brochure" (PDF).
- ^ a b c d e f "Archived copy" (PDF). www.corning.com. Archived from the original (PDF) on 13 April 2015. Retrieved 15 January 2022.
{{cite web}}
: CS1 maint: archived copy as title (link) - ^ Compare Materials: Borosilicate Glass and Macor.
- ^ Corning Macor Maxi-Slab.
- ^ "Macor Glass Ceramic". 26 September 2017.