Polyvinyl butyral/3‐Hydroxy‐2‐naphthoic hydrazide/Poly (methylhydrosiloxane) Composite Coatings for Improved Stainless Steel Anticorrosion in Salt, Acid, and Alkali Solution

Abstract An environmental‐friendly composite material, combining polyvinyl butyral (PVB), 3‐hydroxy‐2‐naphthoic hydrazide (HNH) and poly (methylhydrosiloxane) (PMHS), was prepared by facile mechanical agitation. Hydrazide compounds were used into coating to improve anti‐corrosion capability of 304 stainless steel in different environments. The tested results of structure and surface morphology showed that components were uniformly dispersed into PVB, and prepared coating on substrate was smooth without cracks and holes. According to the results of electrochemical impedance spectroscopy and potentiodynamic polarization, compared with other specimens, the parameters of PVB/HNH/PMHS coatings appeared as the downward change in corrosion current density (I corr ) and upward change in charge transfer resistance (R ct ), which indicated that the PVB/HNH/PMHS had the best anti‐corrosion ability. The long‐term immersion test was processed in 3.5 wt.% NaCl solution at room temperature, which referred that the substrate was protected by PVB/HNH/PMHS coating more than 176 days. This work provides an ideal way of using hydrazide compounds to prevent metal corrosion.