Metal finishing Q&As since 1989

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Is there a way to increase Electrical Conductivity of Coating in Hot Dip Galvanizing Process.

January 13, 2011

Hello,
I am a material scientist and metallurgical engineering. I am working for a steel wire manufacturer company.

As I understand, parameters of furnace, speed of line all effects the surface microstructure, is it possible to increase electrical conductivity of galvanized wires by changing system parameters (effecting microstructure)?

Thank You

Ahmet Alper Kunt
Engineer, working - Adana, Turkey

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Hi, Ahmet.

When people inquire about conductivity it can be hard to know whether they mean bulk conductivity (resistivity) through the zinc metal, or whether they mean surface conductivity, as would be required for a contact surface. Surface resistance would be from zinc corrosion products, or chromate conversion products, and it would seem that a very thin but even chromate conversion coating would be best.

As for bulk resistivity, I know that copper wiring must be very pure copper because even a small amount of impurity drastically reduces the conductivity. In other words, impurities seem to have a lot more to do with it than grain structure. Sorry, I don't know the situation in zinc coatings.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
January 13, 2011

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January 14, 2011

Hello Ted,
Thank you for your answer. I will try to clarify what I mean :

According to Basic Ohm Law, we can think like coating and the base metal behaves like parallel circuit. According to my theory decreasing total resistivity of circuit should increase the conductivity of system.

As in hot dip galvanizing, I found we have 3 methods theoretically.

1- We can chose a better conductive raw material(in this case I am ready to hear any source you may tell-Effects of elements to Steel Alloys) (exp: less silicon, less Mn, less P etc.)

2- We can decrease the resistivity of coating by additives (another surface coating or process-which is not cost effective) like silver, copper.

3- We can change the microstructure of coating to change resistivity.

As I can't play with first 2, I was thinking I may play with microstructure with system parameters.

I am open to any information you may give.

Thanks in advance.

Ahmet Alper Kunt
Engineer, working - Adana, Turkey