Deposition of Columnar-Morphology Lanthanum Zirconate Thermal Barrier Coatings by Solution Precursor Plasma Spraying

Autor: Zhaolin Tang, Amirhossein Yaghtin, Maryam Yaghtin, Pooria Najafisayar, Tom Troczynski
Rok vydání: 2021
Předmět:
Zdroj: Journal of Thermal Spray Technology. 30:1850-1861
ISSN: 1544-1016
1059-9630
Popis: Two types of precursor solutions, including lanthanum nitrate and lanthanum chloride, with zirconium acetate, were used to produce lanthanum zirconate coatings by solution precursor plasma spraying (SPPS). Thermal behavior of the precursor solutions, their rheological properties and atomization patterns were investigated by TGA–DSC, viscosity, surface tension and droplet size measurements, respectively. The chloride precursor led to the formation of impure lanthanum zirconate powder including LaOCl and ZrO2, while the nitrate precursor combined with zirconium acetate produced pure lanthanum zirconate powder after pyrolysis. Increasing the salt concentration from 0.125 to 0.5 M led to the formation of solutions with ~ 2.7 times higher viscosity but ~ 7% lower surface tension. The ethanol based solutions had smaller surface tension compared to the water based (24.3 mN/m vs. 62.7 mN/m), while being more viscous (4.8 cp vs. 3.2 cp). The most significant factor affecting the droplet size in atomized solutions was their viscosity. The 0.5 M water-based solutions with about 28 µm median size droplets injected into the plasma plume produced columnar morphology coatings with ~ 23 vol.% porosity.
Databáze: OpenAIRE
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