Passivation

What is Passivation?

Passivation is a phenomenon that chemical stability become stronger. The passivation caused by a certain passivator (chemicals) is called chemical passivation, such as concentrated HNO3, H2SO4, HClO3, K2Cr2O7, KMnO4 an other antioxidants. Metal get passivated, and the electrode potential moves to the positive direction, then loses the original features. For example, the passivated iron can’t replace copper out in the copper salt. In addition, electricity chemistry also can make metal been passivated. Put Fe in H2SO4 solution as anode, and utilize impressed current to polarizate the anode, and then make the iron potential rise to a certain extent by some tools, finally Fe is passivated. Metal passivation caused by anodic polarization, is called the anode passivation or electrochemical passivation.

Advantages

1, Compared with the traditional physical closing method, passivation treatment absolutely does not increase the thickness or change the color, which improves the accuracy and added value, and make the operation more convenient.

2, There is no chemical reaction in passivation, so passivator can be used repeatedly, which contribute to longer working life and more effective cost.

3, Passivation forms passive film of oxygen molecules with dense, stable performance, and can repair itself in the air at the same time. So passivation is more stable, and has better corrosion resistance, compared with the traditional method that coated with rust-proof oil.