[mrhuyanh]

I made Zinc phosphate for surface metal, iron. But when I test it in the tank, all of surface has yellowing. I watched at youtube, it has spray, smooth.
I made it by ZnO + H3PO4 + HNO3 + NiSO4.
Their surface are cleared oil.
Please help me.
Many thanks.

[Enthalpy]

Does something prevent the iron surface react wit the phosphoric and nitric acids? Phosphates are commonly produced on steel as a protection against corrosion, and they are deep black.

[P]

Zinc Phosphate is pretty nasty to the environment too. Some more modern anti corrosives include:

ATP (Aluminium TriPolyPhosphate) - which is 3 times as effective as Zinc Phosphate as each molecule has 3 phosphate groups to mop the electrons.

Graphene powder - nano graphine plates included at very low levels in primers for steel are apparently showing greatly improved electron scavaging and anti rust performance.

Hope that helps - ATP is readily available. Graphene is still experimental and will cost a bomb to get samples for testing, but you don't need much of it.