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Micrograph 151 and full record
- Micrograph no
- 151
- Brief description
- Alumina-graphite brick
- Keywords
- alumina
, aluminium , antioxidant , brick , carbon, ceramic , composite material , graphite , oxygen , silicon - Categories
- Ceramic, Composite
- System
- Al2O3-C-Si
- Composition
- Al2O3, C up to 30 (wt%), Si few%
- Standard codes
- Reaction
- Processing
- Powders and flake graphite mixed and granulated with phenolic resin or pitch binder. Heated <400°C to decompose binder leaving behind a fine C bond. Antioxidising additives (e.g. Al, Si, SiC, B4C) used to protect the C and graphite flakes. Granulated mix is hot isostatically pressed and fired in reducing atmosphere.
- Applications
- Hollow-ware for steel continuous casting e.g. submerged entry nozzles and shrouds and sliding gate valves.
- Sample preparation
- Polished but unetched.
- Technique
- Reflected light microscopy
- Length bar
- 400 μm
- Further information
- The fused alumina ceramic grain and natural graphite flakes (seen edge on in the micrograph) are held together by a polymer-derived carbon bond and protected from oxidation by a metal (bright Si) which betters oxygen in use to form e.g. SiO2. A true composite material.
- 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
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