Failure Analysis of Commercial Water-Repellent Coatings for High Temperature Plant

플랜트 부품용 상용 발수코팅의 고온 환경 고장 특성 비교 분석

  • Lee, Byung-Ho (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Kim, Hye-young (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Hyeon, Chang-young (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Byeon, Jai-Won (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
  • 이병호 (서울과학기술대학교 신소재공학과) ;
  • 김혜영 (서울과학기술대학교 신소재공학과) ;
  • 현창용 (서울과학기술대학교 신소재공학과) ;
  • 변재원 (서울과학기술대학교 신소재공학과)
  • Received : 2017.02.16
  • Accepted : 2017.02.24
  • Published : 2017.03.25

Abstract

Purpose: The purpose of this study is to evaluate failure characteristic and mechanism of four commercial water-repellent coatings for elevated temperature machinery applications. Method: Thermal degradation was performed for up to 64 thermal cycles. 1 cycle consists of 15 minute holding at 523K under 300rpm revolution and 15 minute-natural cooling. Contact angle was measured and microstructure of the coating layer was observed by using a scanning electron microscope. Results: Four kinds of commercial repellent coating showed hydrophobic or super-hydrophobic property implying that all coatings are suitable for room temperature application. Contact angle of three kinds of commercial coatings decreased rapidly after thermal exposure, while only one specimen having hydrophobic surface showed extremely slow degradation. Conclusion: Observed decrease in contact angle of the coatings were attributed to formation of macro-sized pores and disappearance of micro-protrusion during thermal exposure. Optimum water-repellent coating needs to be selected under the consideration of initial contact angle as sell as service temperature.

Keywords

References

  1. Sam, K. and Phillips, A. (2014), "Technology insights brief: super-hydrophobic coatings and surfaces for power generation and delivery applications". EPRI report, November 11th.
  2. Ganesan, P., Vanaki, S. M., Thoo, K. K., and Chin, W. M. (2016), "Air-side heat transfer characteristics of hydrophobic and super-hydrophobic fin surfaces in heat transfer: A review". International Communications in Heat and Mass Transfer, Vol. 74, pp. 27-35. https://doi.org/10.1016/j.icheatmasstransfer.2016.02.017
  3. Commercial Aviation Safety Team Report (2011), "Fundamentals of gas turbine engines".
  4. Kim, J. Y., Kim, E. K., and Kim, S. S. (2013), "Micronano hierarchical super hydrophobic electrospray-synthesized silica layers". Colloid and Interface Science, Vol. 392, No. 15, pp. 376-381. https://doi.org/10.1016/j.jcis.2012.09.075
  5. Wang, L. (2016), "A study of the mechanical and chemical durability of ultra-ever dry super hydrophobic coating on low carbon steel surface". Colloid and Science A: Physicochemical and Engineering Aspects, Vol. 497, No. 20, pp. 16-27.
  6. Gupta, R., Vaikuntanathan, V., and Sivakumar, D. (2016), "Super hydrophobic qualities of an aluminum surface coated with hydrophobic solution Never Wet". Colloid and Science A: Physicochemical and Engineering Aspects, Vol. 500, No. 5, pp. 45-53.