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Author
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Topic: Space shuttle aluminium frame: Why is it green?
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Fezman92
Member Posts: 1031
From: New Jersey, USA
Registered: Mar 2010
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posted 12-14-2010 10:09 AM
   
When you look at the frame of the shuttle without the tiles, the frame is green. Why is it green? |
garymilgrom
Member Posts: 1966
From: Atlanta, GA
Registered: Feb 2007
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posted 12-14-2010 10:51 AM
It is common for aluminum to be coated to prevent galvanic and environmental oxidation. |
hoorenz
Member Posts: 1031
From: The Netherlands
Registered: Jan 2003
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posted 12-14-2010 11:22 AM
It is called "Super Koropon Primer" (MB0125-055), or simply "Koropon". |
GACspaceguy
Member Posts: 2475
From: Guyton, GA
Registered: Jan 2006
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posted 12-14-2010 11:34 AM
Pure aluminum is very corrosion resistant alloyed aluminum is not. Also the heat treatment applied to the aluminum will also alter the material’s ability to resist corrosion. To combat corrosion a layered approach is applied. For aluminum it starts with the base material and the selected heat treat, then for sheet material a thin layer of pure aluminum is applied during the manufacture of the sheet, (this is referred to as cladding, as pure aluminum is very resistant to corrosion and it protects the alloyed aluminum sub material) this is not so for bar or plate material that will be machined. After fabrication of the part a chemical conversion coating of typically, alodine for sheet metal parts and anodize fro machined parts is applied and that is then protected with an epoxy primer coat to protect the alodine/anodize. It is that epoxy top coat which is typically green in color for aviation (Grumman who built the wing uses light and dark green, some other manufactures use a yellow/green color). |
Fezman92
Member Posts: 1031
From: New Jersey, USA
Registered: Mar 2010
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posted 12-14-2010 02:59 PM
Thanks for the info. Very interesting. |
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