Metal finishing Q&As since 1989

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Autophoretic® Coating

Dear sir:

I want to know why just MS gets coated in Autophoretic® and why not any other metal. Does any other metal gets coated in autophoretic. If so I want to know which metals n how. Is there any new acc paint being invented to coat another metal other than MS. If anyone has any information please tell me.

Narebdra n.Sakhare
- Pune, Maharastra, India
2003

Autophoretic® coatings can be applied to virtually anything that conducts the current, however it is primarily used for MS and Aluminium because the majority of auto manufacturers use these two metals for production.

Robert D Lilley
- Singapore
2003

I currently own a Autophoretic® Coating Company. We apply the Autophoretic® Coating for various automotive components. I want to make sure that there is no misinformation regarding the usage of this product. The 800 series Autophoretic® coating can ONLY be used for ferrous metal substrate. It is best used on cold rolled steel. Hot rolled steel can be painted also,but all the scales must be off the surface. Ferrous castings and forgings can also be painted,but special care must be taken.

Khokan Mitra
- Warren, Michigan, USA
2003

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Different types of autophoretic chemical is available in the industry. Generally it depends upon the chemical reaction between solution and substrate. The substrate like Iron can bring back stability to the bath due to balancing of chemical reactions, whereas other metals may destabilise the bath like Zn and Al whose electrochemical potential is high when compared to Iron and less noble in the series.

Answer is : You will get the coating, but you will be destabilising the bath. You may have to invest on removing the other metals preferentially using a ionic membrane.

Thanks
Prabhakar.R
Chemical and Electrochemical Engineer

Prabhakar Ramachandran
- India
May 23, 2008

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Dear Sir,

As per you hot ferrous forging jobs can be painted, but I want to know what special precaution should be taken at the time of coating. My senors told me that Al is poisonous for ACC 800 bath. Is it true? Secondly what is the role of oxidizer (I know it maintenances oxidation Reduction Potential in the bath, I didn't find any problem if Oxidizer is low in the bath but it creates problem when concentration goes high-Experimental analysis) please tell me your opinion.

Narendra N.Sakhare
- Pune, India
2003

You are on the right track,with the Oxidizer level.We have found that depending on the quality of the casting or forging,you have to find a happy medium for the level of the Oxidizer.You correct a high amount of Al,will impair your coating ability.In order to maintain the right level of Iron,you have to either auto-drain or use IEX. When you auto-drain it will help contain Al level if you are running lot of Forging.You cannot run straight Al castings through the ACC bath.

Khokan Mitra
- Warren, Michigan
2003

DEAR SIR, I WANT TO KNOW WHAT IEX MEANS IS IT AN ION EXCHANGE RESIN IF IT IS THAT I DONE AN EXPERIMENT AND GOT THE POSITIVE RESULT. IF IT IS SOMETHING ELSE please LET ME KNOW.

NARENDRA N. SAKHARE
- Pune, India
2003

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IEX is ion Exchange instrument consist of a vessel contain the ion exchange resin and control unit with sensitive design IEX is approved from Henkel, it could be available at Henkel France .
Not that not any ion exchange resin could be used in the autophoretic bath even you got a positive result in your experiment it's really case sensitive any error may damage your bath

December 7, 2010