Effects of heat treatment on the corrosion resistance of carbon steel coated with LaMgAl₁₁O₁₉ thermal barrier coatings

Abstract

LaMgAl₁₁O₁₉ thermal barrier coatings (TBCs) were applied to carbon steels with a NiCoCrAlY bond coat by plasma spraying. The effects of heat treatment on the corrosion resistance of carbon steel coated with LaMgAl₁₁O₁₉ TBCs were investigated in 3.5wt% NaCl solution using polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results show that a large number of cracks are found in the LaMgAl₁₁O₁₉ TBCs after the samples are heat-treated, including some through-thickness cracks. The corrosion forms of the as-sprayed and heat-treated TBCs are uniform corrosion and pitting corrosion, respectively. The as-sprayed TBCs exhibit three EIS time constants after being immersed for less than 7 d, and then a new time constant appears because of steel substrate corrosion. When the immersion time is increased to 56 d, a Warburg impedance (W) component appears in the EIS data. The EIS data for the heat-treated TBCs exhibit only two time constants after the samples are immersed for less than 14 d, and a new time constant appears when the immersion time is increased further. The heat treatment reduces the corrosion resistance of carbon steel coated with LaMgAl₁₁O₁₉ TBCs. The corrosion products are primarily γ-FeOOH and Fe₃O₄.

Keywords

thermal barrier coatings / carbon steel / corrosion / plasma spraying / heat treatment

References

[1] Kawakita J., Fukushima T., Kuroda S., Kodama T. Corrosion behaviour of HVOF sprayed SUS316L stainless steel in seawater. Corros. Sci., 2002, 44(11): 2561.

[2] C.B. Li, D.H. Chen, W.W. Chen, L. Wang, and D.W. Luo, Corrosion behavior of TiZrNiCuBe metallic glass coatings synthesized by electrospark deposition, Corros. Sci., 84(2014), p. 96.

[3] Liu G., An Y.L., Guo Z.H., Chen J.M., Hou G.L., Chen J. Structure and corrosion behavior of iron-based metallic glass coatings prepared by LPPS. Appl. Surf. Sci., 2012, 258(14): 5380.

[4] Díaz B., Härkönen E., Światowska J., Seyeux A., Maurice V., Ritala M., Marcus P. Corrosion properties of steel protected by nanometre-thick oxide coatings. Corros. Sci., 2014, 82, 208.

[5] Sá Brito V.R.S., Bastos I.N., Costa H.R.M. Corrosion resistance and characterization of metallic coatings deposited by thermal spray on carbon steel. Mater. Des., 2012, 41, 282.

[6] Cano E., Bastidas D.M., Argyropoulos V., Fajardo S., Siatou A., Bastidas J.M., Degriny C. Electrochemical characterization of organic coatings for protection of historic steel artefacts. J. Solid State Electrochem., 2010, 14(3): 453.

[7] Liu Z., Dong Y.C., Chu Z.H., Yang Y., Li Y.Z., Yan D.R. Corrosion behavior of plasma sprayed ceramic and metallic coatings on carbon steel in simulated seawater. Mater. Des., 2013, 52, 630.

[8] Singh V.P., Sil A., Jayaganthan R. A study on sliding and erosive wear behaviour of atmospheric plasma sprayed conventional and nanostructured alumina coatings. Mater. Des., 2011, 32(2): 584.

[9] Gadow R., Lischka M. Lanthanum hexaaluminate — novel thermal barrier coatings for gas turbine applications — materials and process development. Surf. Coat. Technol., 2002, 151-152, 392.

[10] Levi C.G. Emerging materials and processes for thermal barrier systems. Curr. Opin. Solid State Mater. Sci., 2004, 8(1): 77.

[11] Cao X.Q., Vassen R., Stoever D. Ceramic materials for thermal barrier coatings. J. Eur. Ceram. Soc., 2004, 24(1): 1.

[12] Cao X.Q., Zhang Y.F., Zhang J.F., Zhong X.H., Wang Y., Ma H.M., Xu Z.H., He L.M., Lu F. Failure of the plasma-sprayed coating of lanthanum hexaluminate. J. Eur. Ceram. Soc., 2008, 28(10): 1979.

[13] Bansal N.P., Zhu D.M. Thermal properties of oxides with magnetoplumbite structure for advanced thermal barrier coatings. Surf. Coat. Technol., 2008, 202(12): 2698.

[14] Chen X.L., Zhao Y., Gu L.J., Zou B.L., Wang Y., Cao X.Q. Hot corrosion behaviour of plasma sprayed YSZ/LaMgAl₁₁O₁₉ composite coatings in molten sulfate-vanadate salt. Corros. Sci., 2011, 53(6): 2335.

[15] Vaßen R., Jarligo M.O., Steinke T., Mack D.E., Stöver D. Overview on advanced thermal barrier coatings. Surf. Coat. Technol., 2010, 205(4): 938.

[16] Zhang J.F., Zhong X.H., Cheng Y.L., Wang Y., Xu Z.H., Chen X.L., Ma H.M., Zhao Y., Cao X.Q. Thermal-shock resistance of LnMgAl11O19 (Ln = La, Nd, Sm, Gd) with magnetoplumbite structure. J. Alloys Compd., 2009, 482(1-2): 376.

[17] Padture N.P., Gell M., Jordan E.H. Thermal barrier coatings for gas-turbine engine applications. Science, 2002, 296(5566): 280.

[18] Wang L., Wang Y., Sun X.G., He J.Q., Pan Z.Y., Zhou Y., Wu P.L. Influence of pores on the thermal insulation behavior of thermal barrier coatings prepared by atmospheric plasma spray. Mater. Des., 2011, 32(1): 36.

[19] Friedrich C., Gadow R., Schirmer T. Lanthanum hexaaluminate: a new material for atmospheric plasma spraying of advanced thermal barrier coatings. J. Therm. Spray Technol., 2001, 10(4): 592.

[20] Lekatou A., Zois D., Karantzalis A.E., Grimanelis D. Electrochemical behaviour of cermet coatings with a bond coat on Al7075: pseudopassivity, localized corrosion and galvanic effect considerations in a saline environment. Corros. Sci., 2010, 52(8): 2616.

[21] Lekatou A., Zois D., Grimanelis D. Corrosion properties of HVOF cermet coatings with bond coats in an aqueous chloride environment. Thin Solid Films, 2008, 516(16): 5700.

[22] Kassim J., Baird T., Fryer J.R. Electron microscope studies of iron corrosion products in water at room temperature. Corros. Sci., 1982, 22(2): 147.

[23] Lei B., Li M., Zhao Z.X., Wang L., Li Y., Wang F.H. Corrosion mechanism of an Al–BN abradable seal coating system in chloride solution. Corros. Sci., 2014, 79, 198.

[24] Zhang J., Desai V. Evaluation of thickness, porosity and pore shape of plasma sprayed TBC by electrochemical impedance spectroscopy. Surf. Coat. Technol., 2005, 190(1): 98.

[25] Jayaraj B., Desai V.H., Lee C.K., Sohn Y.H. Electrochemical impedance spectroscopy of porous ZrO₂-8wt% Y₂O₃ and thermally grown oxide on nickel aluminide. Mater. Sci. Eng. A, 2004, 372(1–2): 278.

[26] Liu Y.J., Fan X.Z., Zeng S.B., Wang Y., Zou B.L., Gu L.J., Chen X.L., Khan Z.S., Yang D.W., Cao X.Q. Corrosion behavior of coating with plasma sprayed 8YSZ on the surface of carbon steel. J. Rare Earths, 2012, 30(6): 592.

[27] Huang H., Liu C., Ni L.Y., Zhou C.G. Evaluation of microstructural evolution of thermal barrier coatings exposed to Na2SO4 using impedance spectroscopy. Corros. Sci., 2011, 53(4): 1369.

[28] Byeon J.W., Jayaraj B., Vishweswaraiah S., Rhee S., Desai V.H., Sohn Y.H. Non-destructive evaluation of degradation in multi-layered thermal barrier coatings by electrochemical impedance spectroscopy. Mater. Sci. Eng. A, 2005, 407(1-2): 213.

[29] Li M.C., Luo S.Z., Zeng C.L., Shen J.N., Lin H.C., Cao C.N. Corrosion behavior of TiN coated type 316 stainless steel in simulated PEMFC environments. Corros. Sci., 2004, 46(6): 1369.

[30] Liu C., Bi Q., Leyland A., Matthews A. n electrochemical impedance spectroscopy study of the corrosion behaviour of PVD coated steels in 0.5 N NaCl aqueous solution: Part I. Establishment of equivalent circuits for EIS data modelling. Corros. Sci., 2003, 45(6): 1243.