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Full Record for Micrograph 154
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- Micrograph no
- 154
- Brief description
- Macor(TM) Machinable Glass Ceramic
- Keywords
- aluminium
, ceramic , fluorophlogopite, glass , magnesium, mica, oxygen , silicate, silicon - Categories
- Ceramic
- System
- MAS (MgO-Al2O3-SiO2)
- Composition
- SiO2 47, B2O3 8, Al2O3 17, MgO 14, K2O 9, F 6 (wt%)
- Standard codes
- Reaction
- Processing
- Glass composition is melted and heat treated to crystallise using a low temperature nucleation and high temperature growth step.
- Applications
- Precision electrical insulators, vacuum feed-throughs, boundary retainers on the space shuttle. All applications may require a final machining operation to give a precise fit.
- Sample preparation
- Polished but unetched. Sputter coated with thin Au layer to minimise transmission and so loss of reflected signal due to sample transparency.
- Technique
- Reflected light microscopy
- Length bar
- 20 μm
- Further information
- This glass ceramic has the "House of Cards" microstructure consisting of randomly-oriented, flexible, mica-like flakes which arrest or deflect cracks enabling free machining with standard (Black and Decker type) drills. The mica-like phase is fluoroplogopite (KMg3AlSi3O10F2).
- Contributor
- Prof W E Lee
- Organisation
- Department of Engineering Materials, University of Sheffield
- Date
- 10/05/02
- Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales