Summary for trivalent chromium in chrome bath Discussion
trivalent chromium in chrome bath can drop even when plating a small part, and the thread points to bath balance and anode behavior as the likely causes. Payal Mag of Charlotte, North Carolina asked why the trivalent level keeps going down despite using a platinized titanium anode. The reply explains that decorative and hard chrome baths normally contain both hexavalent and trivalent chromium in varying amounts, with a typical decorative bath running around 250 g/L hexavalent and 3 to 4 g/L trivalent. The answerer says nascent oxygen generated at the anode can convert trivalent chromium back to hexavalent, so the relative anode area should be checked. If low trivalent is hurting results, the suggested remedy is to add 0.25 g/L sugar to the bath to raise the trivalent chromium level.
Q. The trivalent chromium is going down no matter, even if I plate small part in chromium bath having platinized titanium anode. Cause and remedy?
Payal Mag
– Charlotte, North Carolina
2001
A. Payal,
Trivalent and hexavalent Chrome are found in varying concentrations in a chrome bath . A regular decorative bath runs well with 250 Hexa and 3 to 4 Gms/lit Tri, and so would a hard chrome bath.
The Nascent oxygen generated at the anode converts Trivalent back to hexa, so the relative anode area needs a look. If lack of trivalent is affecting your results , add 0.25 gram per liter Sugar to the bath. that will push up the trivalent Chrome.
Asif Nurie [deceased]
– New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016
2001