CORROSION PROTECTION OF CARBON STEEL USING ZIRCONIUM OXIDE/SILANE PRETREATMENT AND POWDER COATING

Surface pretreatment plays important role in improvement of corrosion resistance and adhesion of organic coatings. A new generation of metal pretreatments based on nanosize zirconium oxide or ogranosilane film has been investigated recently as an alternative method to phosphatation. In this paper, ZrO 2 /silane composite film on carbon steel was prepared and characterised by field emission scanning electron microscopy, energy dispersive X-ray spectrum and electrochemical measurements. The effect of ZrO 2 /silane surface treatment on the protection properties of powder coating was studied by salt spray test and adhesion measurement. The results obtained showed that ZrO 2 was rapidly precipitated on the steel surface after first 1 minute immersion and ZrO 2 /silane film formed after 4 minutes immersion give best protective properties. Powder coating on carbon steel with ZrO 2 /silane pretreatement has equivalent protection performance like powder coating with  phosphate pretreatment.