Summary for chrome salt consumption Discussion
Chrome salt consumption for 1 sq ft by 1 micron thick is estimated in the reply by calculating the metal volume and converting it to chromic acid usage. The answerer explains that 1 square foot at 1 micron equals about 0.00567 cubic inches of chrome, which at chrome’s density works out to roughly 0.00147 pounds of chromium. Using the molecular weight ratio for H2CrO3 to chromium, the estimated chromic acid consumption is about 0.00288 pounds. However, the answerer cautions that real-world losses from mist evolution and dragout of the viscous chromic acid may make the actual plating consumption close to a rounding error. The reply also notes that more useful guidance would require knowing the specific application and process details, and invites the questioner to explain the situation for more tailored help.
March 5, 2014
Q. Dear sir,
Please let me know chrome salt consumption for 01 sq ft for 01 micron.
Nitin singh
– India
A. Hi Nitin. A square foot is 144 square inches, and a micron is 39.4 millionths of an inch … so you’re talking about .00567 cubic inches of chrome. Chrome weighs about 0.26 pounds per cubic inch, so you have .00147 pounds of chrome.
The molecular weight of H2CrO3 is 102 and the atomic weight of chromium is 52, so you’ll consume about 102/52 x .00147 = .00288 pounds of chromic acid.
But the thing is, the amount lost to mist evolution and the dragout of the viscous chromic acid are liable to make the amount consumed by plating nearly into roundoff error. If you will explain your situation and tell us what you are involved with, we may be able to give you some helful info. Good luck!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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March 2014
April 4, 2014
A. Usually we do not calculate the consumption in this way — one reason is because of the uneven thickness distribution.
A better approximation you will get from experience with the bath.
Plating complicated shaped parts will result in higher drag-out but also higher thickness differences.
Other aspect that you have to keep in mind is the evaporation.
Vlad Manta
– Oradea, Romania