Volcanic ash infiltration resistance of new-generation thermal barrier coatings at 1150 °C

• Published in: Surface & coatings technology 2020-11, Vol.401, p.126226, Article 126226
• Main Authors: Kandasamy, Praveen, Govindarajan, Sivakumar, Gurusamy, Shamnugavelayutham
• Format: Article
• Language: English
• Subjects: Aluminosilicates; Anorthite; Apatite; Calcium magnesium silicates; Coatings; Gadolinium; Gadolinium oxide; Gadolinium oxide doped lanthanum cerate; Gadolinium oxides; Gd apatite; Infiltration; Interaction layer; Lanthanum; Plasma spraying; Solution precursor plasma spray; Thermal barrier coatings; Thermal resistance; Volcanic ash; Yttria-stabilized zirconia; Yttrium oxide; Zirconium dioxide
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2020.126226

The recent developments in advanced materials for thermal barrier coatings (TBCs) have put thrust towards the progress of new materials due to their superior performance over the state-of-the-art yttria-stabilized zirconia (YSZ). Lanthanum cerate (La2Ce2O7, LC) is one of the promising candidates used against the infiltration of calcium magnesium alumino-silicate (CMAS) melt. For a highly efficient low thermally conductive material, gadolinium oxide doped lanthanum cerate ((La0.9Gd0.1)2Ce2O7, Gd-LC) was synthesized as a new aspirant. Deposits of atmospheric plasma sprayed (APS) LC, Gd-LC coatings were generated, and their interactions against the infiltration of volcanic ash were studied. Both the coatings formed the apatite phase interaction layer, with a considerable quantity of anorthite and spinel phases. On comparison, Gd-LC showed significantly more resistance than LC coatings because of the presence of Gd apatite in Gd-LC coatings. Further, we developed Gd-LC single layer, double-layer, and composite hybrid coatings by employing APS and solution precursor plasma spraying process (SPPS). Phase evolution and microstructural features were studied and are discussed in detail. •LC and Gd-LC coatings were developed by plasma spraying and its mitigations against volcanic ash infiltration were studied.•LC and Gd-LC coatings form the apatite phase interaction layer when interacting with volcanic ash.•On comparing the LC and Gd-LC coatings, Gd-LC coatings show good resistance because of of its apatite phase composition.•Single/double layered and hybrid TBCs were developed; and its phase and microstructural characteristics were studied.