Metal finishing Q&As since 1989

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Zirconium in place of zinc phosphate for powder coat preparation?

Does anyone have any experience with zirconium use in place of zinc phosphating for powder coat applications?

Linda Nelson
powder coat engineer - Norman, Oklahoma
May 12, 2008

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May 15, 2008

Hi,
I have only come across its use once at a customer that I visited to carry out a temperature oven check.
They were processing mainly aluminium window cills along with a small percentage of mild steel components. However, on the day of my visit everything being processed was of mild steel. What I saw was that all the metal items exiting the pre-treatment area were covered in flash rust. On speaking to the pre-treatment rep he stated that the customer should have only been treating a few items of mild steel as he had made them aware that the zirconium was only suitable for aluminium. Apparently the flash rusting was acceptable to him as they were only supposed to coat a few metal items per day.
Unfortunately, I am not familiar with this product but it gives you some inkling to what questions to ask your supplier.

Terry Hickling
Birmingham, United Kingdom

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Hi

I'm using zirconium phosphate on Al, CRS and HRS, if You have any questions just ask. Generally it's cheaper in use lower temp less waste, much lower water consumption, less dumping. From my experiences that what You saw it wasn't flash rusting it was over phosphate, because zirconium phosphate gives You on steel coating from blue like iron to "old gold" end after that You will have over coating which looks sometimes like rust = orange powder.

Marek
- Poland
May 15, 2008

Ed. note: Thanks, Marek, but name and town please.

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Hi

I'm using zirconium phosphate on alu and steel. Version that I'm using is designed to pre treat both in one bath.Basing on my experiences that what You saw was over phosphate. zp can give You a coating from similar to iron phosphate "blue" - thin coat to "old gold" heavy and at the end orange powder - to heavy :). Generally, zp is much cheaper in use less waste, lower water consumption lower temp etc. Maybe You have any specific questions?

Marek
- Poland
May 16, 2008

Ed. note: we must have full your name and town, Marek. Sorry, this is not an anonymous service. Thanks.

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Thanks Merek, as stated I had not come across the use of this product and the finish was brown/golden.
I took it for granted that the pre-treatment rep new what he was talking about when he informed me it was only used on Al. Thanks for your input and as I always say you never cease learning. I will pass your comments on to the PC Company.

Terry Hickling
Birmingham, United Kingdom
May 16, 2008