Prolong passivation of a novel Fe-based amorphous coating derived from high P pig iron

Strong passivation tendency and excellent corrosion resistance of amorphous coatings on mild steel prepared from a newly developed novel composition(Fe66.59C11.70P7.58Mn0.37Si2.86Cr1.72Mo0.92B8.26, (atom percent) are reported. The composition is a derivative of high P containing Pig iron, and atmospheric plasma spray technique was used for coating. Current-transient response at passivating potential for each coating and MS was recorded to predict the passive tendency of the coatings. The corrosion monitoring of a coating was executed for about 3 months in a 3.5 (weight /volume%) NaCl solution at free corrosion potential to understand its corrosion im-munity. Extensive impedance measurements were carried out to understand the passivation and the nature of passive film on coated samples. The monitoring experiment indicates requirement of prolong duration to achieve the passivation for lean chemistry glass coating. The Fe substituted chromate, borate, and phosphate phases on all the coatings are attributed to the excellent passivation of coatings.

Automated summary

The amorphous coatings prepared from a newly developed composition showed excellent corrosion resistance and strong passivation tendency on mild steel. The coatings were produced using atmospheric plasma spray technique. Current-transient response and corrosion monitoring experiments were conducted to evaluate the passivation ability and corrosion immunity of the coatings. Extensive impedance measurements were performed to analyze the nature of the passive film on the coated samples. The presence of Fe substituted chromate, borate, and phosphate phases contributed to the outstanding passivation of the coatings.