Performance of zinc phosphate coatings obtained by cathodic electrochemical treatment in accelerated corrosion tests

摘要: Abstract The formation of zinc phosphate coating by cathodic electrochemical treatment and evaluation its corrosion resistance is addressed. behaviour cathodically phosphated mild steel substrate in 3.5% sodium chloride solution exhibits the stability these coatings, which lasts for a week's time with no red rust formation. Salt spray test convincingly proves white scribed region on painted substrates most part surface unpainted surface. protective ability product formed coated evidenced decrease loss weight due to uncoated steel, when it galvanically coupled steel. Potentiodynamic polarization curves reveal that E corr shifts towards higher values (in range −1000 −1100 mV versus SCE) compared conventionally substrates. i value also very high coatings. EIS studies dissolution predominant reaction during initial stages immersion. Subsequently, non-metallic nature progressively increased products, turn enables an increase immersion time. products may consist oxide hydroxychloride.