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Electronegativity effect on Electroplating

I am doing a project on electroplating. My hypothesis is: Does electronegativity relate to the effectiveness of how much a metal plates? The problem was: How much plating occurs between each metal varying in electronegativity? Based on my data, electronegativity does not relate to the effectiveness of how much a metal plates. My reason for this can be explained by using the Electronegativity Ranking, which I created with some help from the Pauling Scale, and compare it to the Ranked Results. I would REALLY APPRECIATE it if someone can help me by telling me some possible factors that can relate to the effectiveness of how much a metal plates and why. ANY help would be REALLY be useful, THANK YOU.

Jose D.
student at Alief Hastings HS - Houston, Texas, United States
2004

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Maybe your data, hypothesis, and conclusions are clear in your mind, Jose, but I have little idea what you're trying to say.

Electronegativity has a profound effect on plating, but maybe not within the range you are thinking or for the reasons you are thinking. Many metals cannot be plated (from water / aqueous solution) at all because they are too electronegative; this includes the light metals like sodium, but also metals like Aluminum and Magnesium.

Some metals like gold, copper, and nickel can be plated at nearly 100 percent efficiency (that is, in accordance with Faraday's Law), whereas other metals like chromium are plateable but 90 percent of the current goes into liberating hydrogen instead of reducing chrome.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

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First of two simultaneous responses --

I think you are asking whether the electronegativity of a metal in relation to the electrochemical series (ECS) has any effect on its ability to be electrochemically deposited . To this the answer is a strong yes. This potential is the reduction potential of the metal. The more electronegative the metal, the less likely it is capable of being deposited from an aqueous system. The most electronegative metal that is normally plated is zinc, with a potential (vs hydrogen) of -0.762V. Other more esoteric metals can also be plated, but that is outside your technical needs. Aluminium, for instance, has a potential of -1.67V and this certainly cannot be plated from an aqueous medium. The lower the potential, the greater the amount of hydrogen that will be discharged during the plating process. This is a BAD THING as it reduces the efficiency of the metal deposition. Metals with a potential above hydrogen (i.e., over 0.00V) will generally plate with an efficiency of approaching 100%; the higher the electropositive potential, the easier it is to plate. Or at least that is what the theory says!

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004

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Second of two simultaneous responses --

THANKS A LOT Mr. Mooney for your response, but I'm still not sure of what other factors there could be. The metals that I have tested were based on the Activity series due to the fact that I did not want a reaction to occur but actual plating. The electrode used for this experiment were metal nails, so all of the metals that I tested were in a higher position than Iron on the activity series. The metal solutions used were BaCl2, CaCl2, MgCl2, AlCl3, ZnCl2, FeCl2. AlCl3 was supposed be the third metal in having the most plating but came out to be tied with CaCl2 for last place. Other than this, the rest of the metals came to a logical ranking (based on my hypothesis). If my hypothesis was wrong, then what are other factors that relate to the amount of plating. Could ionization be another factor? Could the amount of the metal in the solution be another factor as well? Why or why not? Are there other factors? PLEASE HELP ME. THANK YOU.

Jose D. [last name deleted for privacy by Editor]
student at Alief Hastings HS - Houston, Texas, United States
2004