corrosion plating for automotive s.g. iron castings 2

[kelv]

okay,
I have an automotive component (sg iron casting, car suspension part) which requires some kind of anti-corrosion treatment for mass production.
typical options are; zinc plate and passivate, black phosphate and paint, chemical blacking, etc.
My problem is that I need to treat some of the machined features after the machining process. I cannot find a 'selective' plating process although 'kemps' handbook describes one. Has anyone had experiance of this?
Also, I need to understand fully how plating processes etc. work - but I haven't found any quality links, any suggestions....
many thanks in advance...

 

[TVP]

kelv,

Some good sites on corrosion protection/surface treatments are

Automotive Finishing (

http://www.afonline.com/)

Products Finishing (

http://www.pfonline.com/)

Finishing.com (

http://www.finishing.com)

Both AF & PF are part of Gardner Publishing, with AF explicity on Automotive stuff. IF you have access to a decent library (University, etc.) then check out Volume 5 of the ASM Handbook series titled "Surface Engineering". As with any of the ASM Handbooks (there are 21 in all covering anything related to materials, forming, casting, NDE/NDT, composites, etc.) it is authoritative coverage on the various types of corrosion protection methods.

I am unclear on what exactly you are asking for regarding selective plating. Would you have this component coated in some manner, then machine it, and then look to treat the machined surface afterwards? Most iron suspension components go through an organic coating process (cathodic electrocoat), which deposits around 20 microns of epoxy on the surface. I am not very familiar with selective plating treatments, so you may want to consult some actual suppliers on this.