Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Micrograph 154 and full record
Micrograph Library Browse the libraryAdvanced searchSystemsCompositionsTechniquesKeywordsPhase diagrams
HelpPreferencesAbout the micrograph libraryTerms of useContribute micrographs!FeedbackLinksCredits Print this page
micrograph index montage

Micrograph 154 and full record

Link to image file for micrograph 154
Micrograph no
154
Brief description
Macor(TM) Machinable Glass Ceramic
Keywords
aluminium Link to MATTER Glossary entry for aluminium, ceramic Link to MATTER Glossary entry for ceramic, fluorophlogopite, glass Link to MATTER Glossary entry for glass, magnesium, mica, oxygen Link to MATTER Glossary entry for oxygen, silicate, silicon Link to MATTER Glossary entry for 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-NonCommercial-ShareAlike 4.0 International

View image alone .. in a new window

View micrograph only

View full record only

Help is available on downloading images