Study of the Effect of Immersion Time in Zinc Phosphate Solution on the Corrosion Protection Efficiency of Steel

Abstract

zinc phosphate layers were synthesized on steel surfaces through an electroless deposition method under controlled temperature and pH conditions. The deposition process was conducted for immersion periods of 30, 60, 90, and 120 minutes in the phosphate bath. The surface morphology of the coatings was examined using optical microscopy, and their corrosion resistance was evaluated by weight loss tests carried out within a 3.5% sodium chloride medium. The results revealed a gradual improvement in both coating thickness and surface coverage with increasing immersion time. Dense and uniform layers were obtained after 90 and 120 minutes, with the highest corrosion resistance achieved at 120 minutes. After 24 hours of exposure, the specimen treated for 120 minutes exhibited a minimal weight loss of 0.33 g/m², confirming its superior protective performance.