Significance of Phosphating and Chromatising in 3 Layer PE Coating

Question

Significance of Phosphating and Chromatising in 3 Layer PE Coating

vibhormiglani (Mechanical)

(OP)

17 Sep 03 20:36

We are basically engaged in 3 Layer PE coating on carbon steel pipes. Now a days clients are asking for chemical pre-treatment on the pipes before coating which includes Phosphating and chromating. We want to know how these chemical treatments mentioned above help to improve the coating quality.

NickE (Materials) · Answer 1 · 2003-09-18 09:40:34

From what I remember the phosphatizing process provides for better adhesion of coatings.

nick

CoryPad (Materials) · Answer 2 · 2003-09-18 20:32:40

Phosphating and chromating are used as primers on metal surfaces to improve adhesion of subsequent layers. They also add to the corrosion resistance of steel parts because of barrier and polarizing effects.

Regards,

Cory

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vibhormiglani (Mechanical) · Answer 3 · 2003-09-19 19:30:47

What is barrier and polarizing effects in corrosion resistance of steel parts when pre-treated with phosphoric acid / chromate?

vibhormiglani (Mechanical) · Answer 4 · 2003-09-19 19:33:12

We would like to know how phosphoric acid helps in removal of salts from blasted carbon steel surface?

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Significance of Phosphating and Chromatising in 3 Layer PE Coating