Page 37 - PCMI Journal July 2018

David Allen | Emeritus Professor | Cranfield University | UK Photochemical Machining of Aerospace Materials
5/31/18
Typical ‘etched’ aerospace applications include...
Connectors and contacts
Fan Cooling
Interior trim
Intake grilles
Air Coolers
Heat exchangers
Heater elements
Fuselage skins
The effects of the passive layer on the surface of aluminium
The rate of etch of the passive layer < the rate of etch of the aluminium. Short etch times give a rough surface finish and low etch rates.
However, once the passive layer is removed then the surface finish and etch rate improve.
Photoresist
Oxide layer
Aluminium
Issue 131 July 2018 PCMI Journal 36
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