Advance Effect of Rare Earth Nitrates on Green Process of Phosphating

It had validated by experiments why appending rare earth nitrate (REN) into the bath affects notably on development of coating-forming, corrosion resistance as well as on urgency varieties of appearance and component of the coating. The causation rests with the fact that REN not only makes metal surface depolarized and cathodic reactions accelerated, but also acts as crystal nucleus. with gel forms on the metal surface to speed up the coating-forming and develop the anti-corrosion capacity of the coating. The optimal level of addition of REN is 30-55 mg.L-1. In recent years because of REN appended in the bath, the steel phosphating technique, a traditional and important craftwork far and wide employed in steel over-coating and corrosion protection of the surface, has been endowed with new content and energy, and some experiences have been accumulated [1-4]. But a lot of things about it remains worthwhile to be discussed due to the investigation time on it is not long inland. The experiments presented in the paper for development of coating-forming, corrosion resistance by appending REN have been done to expect to get some profitable elicitation.