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-----Trivalent Black Passivation analysis (cobalt base)
September 29, 2011
Hello All
My question is that I have to use a black trivalent passivation in which cobalt is present, as cobalt helps in black passivation film formation. Is there any analysis procedure to check the passivation consumption or for its replenishment; how much I have to add black chromate after analysing in the lab? As my chemist has suggested that there is no analysis procedure and only procedure is the AAS (Atomic Absorption Spectro)
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Regards
Sean Aarchr
plating shop employee - India
What other metals are present besides Cr and Co?
If the answer is 'none', you can likely determine Co by adding ammonia, filtering out Cr(OH)3, then titrating the filtrate with 0.1 M EDTA, using murexide
[affil link] as indicator.
That's an educated guess. Consult Meites Handbook of Analytical Chemistry
⇦[this on
Amazon affil links]. I do not doubt that there are multiple titrimetric procedures for Co described there.
Dave Wichern
Consultant - The Bronx, New York
October 3, 2011
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