용융 Zn-Mg에서의 다양한 금속 재질에 대한 내침식 특성

Abstract

To enhance the corrosion properties, metallic coatings containing Zn are currently used widely for applying as protective coating for steel by forming the barrier products. In addition to creating a barrier between steel and the environment, Zn also has roll of anode to steel so preferentially corrode and protect the steel against rusting when the coating is damaged. However, not only the price of Zn has increased constantly, but also supply and demand of Zn are unstable. In order to solve this problem, the governments all around the world and steel production companies have attempted to reduce the Zn consumption or develop the substitutions offering improved corrosion resistance without increasing coating thickness. Thus, many steel companies have attempted to increase corrosion resistance by developing new alloys with aluminum, iron, nickel, and magnesium. Especially, among of them, Zn-Mg alloys have superior resistance to conventional Zn within 1~16wt.%Mg. Zn, as a more noble metal than magnesium, is well known to positively affect the corrosion resistance with Mg addition. Also, there are some papers that Mg affects the corrosion products such as Zn5(OH)8Cl2·H2O (simonkolleite), which can delay the formation of final corrosion product ZnO. For this reason, Zn-Mg coatings have been highlighted as a potential generation of galvanized steel, but detailed information of other research is limited in open literature. Furthermore, the research of reaction between materials in the working environment and corrosive materials(molten Zn-Mg) is necessary in order to apply the Zn-Mg coating to the real industry. In the present work, static corrosion tests were carried out by immersing the metal materials and ceramic into the molten Zn-Mg. We prepared STS 310S, 316L, aluminized 316L, Hastelloy X, SiC bulk specimens for immersion test and tried to select what commercial material is suitable for a hardware material to supply the molten Zn-Mg.