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Cadmium plating conversion factor

2006

Hello,
I'm a chemical engineer working in a private organization.I'm doing cadmium plating according to BAC 5701. but in that respect I have given control in ampere square feet but I want to do it by voltage not by current ? Can you kindly tell me any formula which converts ampere per square feet into voltage.
regards,
note: an early response will be highly appreciated sir.

Iftikkhar Ali
plating private limited - Karachi, Sindh, Pakistan

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Sorry, that isn't possible, Mr. Ali. Voltage is analogous to water pressure, while current is analogous to flow. Per Ohm's Law Current equals Voltage divided by resistance, but the resistance depends on many factors including the distance from the anode to the cathode.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

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Dear sir,
thanx a lot for immediate response. Can you guide me about cadmium plating with thickness of 0.0005 inches and ultrachromate passivation. I have been asked for cadmium plating with 10-20 ampere square feet of current. but I have control with volt meter and ampere meter shows only ampere when I give voltage not the ampere square feet.how can I perform it at 10-20 asf? Please answer as quickly. It will be so kind if any one can give me guide line. In fact I'm confused about ampere/square feet. I have only voltmeter control and ampere meter only for ampere readings.

Iftikkhar Ali
plating private limited - Karachi, Sindh, Pakistan
2006

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Dear sir,
Can you guide me -- I have to do cadmium plating at 10-20 ampere square feet.
How do I have to control it; either I have to give voltage also or I have to control it by current.
At my system I give 2 to 3 volts then it draws current.
Also want to know that square feet is area of bath or part which is plated?

iftikhar ali, chemical engineer
plating private limited - Karachi sindh Pakistan
2006

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Hello, Mr. Ali.

Measure the surface area of the part that you are trying to plate, and express that area in square feet. Now multiply by 10 amperes per square foot, and that is the amperage you need to use.

The longer that you plate, the thicker the plating. The higher amperage that you plate at, the thicker the plating, but there are limitations to how high the amperage should be. The relationship of thickness to time and current is called Faraday's Law of Electrolysis. The Metal Finishing Guidebook has a table showing thickness as a function of time and current.

The answers you need require an electroplating textbook with a chapter on electricity and a chapter on electrochemistry. The AESF (www.nasf.org) has a training course on this, and most of the books on our "must-have" book list would be helpful. Most cadmium plating is done from cyanide, which is a deadly chemical; you should be fully trained in its use.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June , 2006