In Reply to: need help on aluminizing mirrors posted by charlie on 07/18/01 at 2:20 PM:
Hi charlie,
I think others have already suggested the best practices but still I want to clarify certain parameters. Al coatings need high degree of cleanliness of the substrate and any fine layer of grease left causes poor adhesssion. I achieved best results using following conditions:
Glow discharge : Atleast 15 minutes
Vacuum 2-5*10^-5 mbar
Atleast 2000-2500A sio2 over coat
Evoporation rate : atleast 100A( Even though the final thickness is 500A)
Temp : ~ 30 - 50C
Glow discharge and evoporation rate are very important for getting adhession and over coat sio2 or MgF2/CeO2/MgF2/Ceo2 will help aberration (scrach freeness) and reflectance.
Thanks and regards
Krishna Oruganti.