The formation behavior of a passive state film on the surface of STS304 in electrolytic solution was analyzed to determine its metallic ion composition. The properties of passive state films vary depending on the Fe and Cr ions in the electrolytic solution. It was observed that the passive state film surface became flat and glossy as the concentration of Fe and Cr ions in the electrolytic solution increased. The corrosion resistance property of the passive state film was proportional to the amount of Fe and Cr in the electrolytic solution. An initial passive state film with high Fe concentration was formed on the surface of STS304 during early electrolytic polishing. Osmotic pressure of Fe ions occurs between the passive state film and electrolytic solution due to the Fe ion concentration gradient. The Fe in the passive state film is dissolved into the electrolyte, and Cr fills up the Fe ion vacancies. As a result, a good corrosion-resistant floating film was formed. The more Fe ions in the electrolytic solution, the faster the film is formed, and as a result, a flat passive state film containing a large amount of Cr can be formed.

Abstract
1. 서 론
2. 실험 방법
3. 결과 및 고찰
4. 결 론
References

• 오종수(㈜나눌) | Jong Su Oh (NANUL Co. Ltd, 25, Juyeom-ro 73beon-gil, Michuhol-gu, Incheon 22122, Republic of Korea)
• 강은영(인하대학교 신소재공학과) | Eun-Young Kang (Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Incheon 22212, Republic of Korea)
• 정대용(인하대학교 신소재공학과) | Dae-Yong Jeong (Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Incheon 22212, Republic of Korea) Corresponding author