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Replacement of Chromic Acid for Desmutting Molybdenum




2006

We use chromic acid (Cr+6) to etch molybdenum pins. The molybdenum pins are flame sealed to glass wafers with exposed portions of the pins that have oxidized. Corporate would like us to eliminate the use of chromic acid.
The process goes like this:
Descaling using 29% Ammonium Hydroxide; Removal of the oxide coating using a mixture of nitric, hydrochloric and sulfuric acid (this process leaves black spots from the oxidation); Black spot removal using mixture of sulfuric acid and chromic acid

Is anyone aware of a process that can be substituted that would eliminate the chromic acid, but still remove the oxidation/black spots from the Mo pins?

Gary Follett
Electronics Manufacturer - Minneapolis, Minnesota




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