Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Zinc phosphating bath
2005
Hello!
I am a metal engineer. I study about converting coating(tri cationic phosphating bath).My coating bath ingredients is:
1.H3PO4:10(g/lit)
2.zinc oxide
⇦this on
eBay or
Amazon [affil links]
:6(g/lit)
3.NICKEL NITRATE:3
4.MN(NO3)2:1
5.NaNO2(ACCELERATOR):1
ph=3 T=50-60(c) t=5-7(min)
My process stages consist of:oil cleaning-acid washing(sulfuric acid5%)-water rinse-phosphating bath-water rinse
The result coating is very smooth, dense and light gray color.but after two time immersion coating the bath is not work
good. My coating pieces are steel plates.(st37)
how can I improve the bath?
must I add other materials in working bath?
what are the best conditions of my bath?
what must I add to the bath for increase the salt spray time?
my bath sludge is very high. The way of coating is immersion. how can I solve this problem.
- Tehran
Hi Amir,
Your primary problem is that you appear to be using a "home-brewed" zinc phosphating bath. I suggest to contact a supplier of pretreatment chemicals and they can suggest a product that is properly formulated for your application.
- Naperville, Illinois
2005
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