A Study on the Improvement of Oxidation and Corrosion Resistance of Stainless Steel by Sol-Gel Ceramic Coating (II); Effect on Oxidation and Corrosion REsistance of <TEX>$CeO_2$</TEX> Stabilized Zirconia Thin Film

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J. Korean Ceram. Soc. > Volume 32(1); 1995 > Article

Journal of the Korean Ceramic Society 1995;32(1): 95.

졸-겔 세라믹 코팅에 의한 스테인레스강의 내산화 및 내식성 향상에 관한 연구 (II);$CeO_2$ 안정화 지르코니아 박막의 내산화 및 내식성 효과

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고려대학교 재료공학과

A Study on the Improvement of Oxidation and Corrosion Resistance of Stainless Steel by Sol-Gel Ceramic Coating (II); Effect on Oxidation and Corrosion REsistance of $CeO_2$ Stabilized Zirconia Thin Film

ABSTRACT

Ceria(CeO2) stabilized zirconia(CeSZ) sol was synthesized with zirconium n-butoxide Zr(OC4H9)4 and cerium nitrate hexahydrate Ce(NO3)3.6H2O as precursors and ethylacetoacetate(EAcAc) as a chelating agent under atmosphere. CeSZ films were deposited on AISI 304 stainless steel using the prepared polymeric sol by dipcoating and the coating characteristics were investigated by XRD, ellipsometry, scratch test and SEM. The CeSZ film began to crystallize from amorphous to tetragonal phase at 40$0^{circ}C$ and it was not converted into monoclinic phase up to 100$0^{circ}C$ by the addition of 16mol% CeO2 as a stabilizer which could suppress phase transformation of zirconia. The CeSZ films were prepared by varying the EAcAc contents and the cncentration of CeSZ sol and measured the thickness and refractive index. From these results, it was found that the EAcAc contents and concentration of CeSZ coating sol evidently affect the densification of CeSZ film. The CeSZ film coated with 0.4M CeSZ sol and heat-treated at $600^{circ}C$ for 10min had thickness of 50nm and 17% porosity. The CeSZ film on 304 stainless steel effectively acted as a protective layer against oxidation up to 80$0^{circ}C$ and had superior corrosion resistance in 25% H2SO4 solution for 4.5 hrs.

Key words: Sol-gel, CeSZ (Cerla Stabilized Zirconia) film, 304 stainless steel, Oxidatio, Corrosion