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Effects of heat treatment on the corrosion resistance of carbon steel coated with LaMgAl11O19thermal barrier coatings
LaMgAl11O19thermal 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 LaMgAl11O19TBCs were investigated in 3.5wt% Na Cl solution using polarization curves, electroch...
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Published in: | 矿物冶金与材料学报:英文版 2015 (10), p.1050-1059 |
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Main Author: | |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | LaMgAl11O19thermal 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 LaMgAl11O19TBCs were investigated in 3.5wt% Na Cl 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 LaMgAl11O19TBCs 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 LaMgAl11O19TBCs. The corrosion products are primarily γ-Fe OOH and Fe3O4. |
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ISSN: | 1674-4799 1869-103X |