Evaluation of the Corrosion Resistance of Zn-Coated Steel as a Function of the Temperature of the Cr-free Solution Used to Coat the Steel

J. Ocean Eng. Technol. 2010;24(5):60-66.

Seo Hyun-Soo,Moon Hee-Joon,Kim Jong-Soon,Ahn Seok-Hwan,Moon Chang-Kwon,Nam Ki-Woo

Defence Agency for Technology and Quality,Graduate School Pukyong National University,NGE Tech Ltd.,Bukyong Education Center for Vehicle Safety Component Technology Pukyong National University,Materials Science and Engineering Pukyong National Universi

Cr-free 코팅액에 의한 아연도금강판의 열처리 온도에 따른 내식특성

서현수,문희준,김종순,안석환,문창권,남기우

국방기술품질원,부경대학교 대학원,엔지텍,부경대학교 수송기계안전편의융합부품소재인재양성센터,부경대학교 신소재공학부,부경대학교 신소재공학부

Keywords: Heat treatment temperature, Organic/inorganic hybrid, Electrolytic Galvanized, Hot-dip Galvanized, Salt spray test, Coating solution, White rust

핵심용어: 열처리 온도, 유/무기 하이브리드, 전기아연도금, 용융아연도금, 염수분무시험, 코팅액, 백청

Abstract

Zinc has a number of characteristics that make it well suited for use as a coating to protecting iron and steel products from corrosion. Its excellent corrosion resistance in most environments accounts for its successful use as a protective coating on a variety of products and in many exposure conditions. The excellent field performance of zinc coatings results from their ability to form dense, adherent films that corrode at a rate that ranges from 1% to 10% of the corrosion rate of ferrous materials, depending on the environment. Recently, EU RoHS and EU ELV prohibited the use of materials that adversely affect the environment, such as Pb, Hg, Cd, and $Cr^{+6}$. In this study, environmentally-friendly, Cr-free solutions (epoxy solution, acrylic solution, and urethane solution S-700) and organic/inorganic solution with Si; LRO-317) were used to evaluate the corrosion resistance of zinc-coated steel subjected to a saltwater spray for 72 hours. The coating of urethane solution (S-700) was best among the three kinds of solution with heat treatment during five minutes at $190^{circ}F$. Test specimens with S-700 and LRO-317 coating were heat treated in a drying oven at 170, 180, 190, 200, and $210^{circ}C$ for five minutes. The results show that the optimum corrosion resistance was $190^{circ}C$ in EGI and $170^{circ}C$ in HDGI, respectively.