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"Zinc phosphating bath"
I am a metal engineer. I study about converting coating(tri cationic phosphating bath).My coating bath ingredients is:
ph=3 T=50-60(c) t=5-7(min)
My process stages cosist of:oil cleaning-acid washing(sulforic 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 saltspray time?
my bath sludge is very high.the way of coating is immersion. how can I solve this problem.
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