용액 분위기에 따른 용융아연도금 강판의 내식성에 관한 전기화학적 평가

Abstract

Hot-dip galvanizing of iron and steel has been widely used to many kinds of steel structures of various industrial fields. Therefore it is estimated that approximately 40% of the world production of Zinc is consumed in hot-dip galvanizing of iron and steel and the success of zinc can be largely attributed to ease of application, low cost and high corrosion resistance. However more high corrosion resistance than pure zinc coating is needed to some steel structures exposed to severe corrosive environments due to contaminated water, acid rain and industrial water pollution etc. Thus galvalume or chromate treatment having better corrosion resistance than pure zinc coating was developed to use severe environmental condition. Although their corrosion resistance of galvalume, chromate and hot-dip zinc coating was well known, there was little studies which of them have a high corrosion resistance in neutral, acid and alkali solution respectively.

In this study three kinds of materials mentioned above were investigated about corrosion resistance each other in neutral sea water, acid and alkali solution respectively.

Galvalume and choromate treatment steels showed a good corrosion resistance than hot-dip zinc coating in sea water solution. And chormate treatment in 1% H2SO4 solution and 1% NaOH solution also showed a good corrosion resistance compared to both hot-dip zinc coation and galvalume steel. In particular corrosion resistance of galvalume steel was apparently improved in 1% H2SO4 solution and sea water solution than hot-dip zinc coating, however its corrosion resistance in 1% NaOH solution was decreased than sea water solution.