Assessment of CrFeCoNi and AlCrFeCoNi High-Entropy Alloys as Bond Coats for Thermal Barrier Coatings

• High-entropy alloys (HEAs) represent a relatively new group of multicomponent alloys that have shown great potential for applications requiring tribological and oxidation resistant properties. Consequently, thermally sprayed coatings of different HEA chemistries have received increasing research attention. In this paper, atomized equimolar CrFeCoNi and AlCrFeCoNi feedstocks were used for high velocity air-fuel spraying (HVAF) to produce overlay coatings using two different nozzle configurations. The microstructure, phase constitution and hardness of the coatings were analyzed along with the primary aim of testing the coatings for their oxidation behavior. The performance of the two HEA chemistries was compared with two commercial MCrAlY coatings that are well-established bond coat materials for thermal barrier coatings (TBCs). An investigation was conducted to test the coatings’ performance as bond coats by applying suspension plasma sprayed yttria-stabilized zirconia top coats and evaluating the thermal cycling behavior of the TBCs. The AlCrFeCoNi-coating was found to demonstrate a lower oxidation rate than the CrFeCoNi-coating. However, the AlCrFeCoNi-coating was found to form more rapid oxide scales compared with the commercial bond coat material that also contained reactive elements. © 2022, The Author(s).

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

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Air; Aluminum alloys; Cobalt alloys; Entropy; High-entropy alloys; Iron alloys; Oxidation; Oxidation resistance; Plasma jets; Plasma spraying; Sprayed coatings; Thermal barrier coatings; Yttria stabilized zirconia; Yttrium oxide; Alloy chemistry; Bond coat materials; Bond coats; High entropy alloys; High velocity air fuels; Isothermal oxidations; Multi-component alloy; Oxidation resistant; Property; Thermally sprayed coatings; Chromium alloys

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