Plasma spray deposition of yttrium oxide on graphite, coating characterization and interaction with molten uranium

Yttrium oxide coatings on graphite substrates were prepared by atmospheric plasma spray technique. Temperature and velocity of the yttrium oxide particles during the plasma spray process were measured by ‘spraywatch’ diagnostics system. Coatings were characterized for phase composition, microstructure and thermal stability. Dense adherent coatings could be deposited at 24 kW power. Corrosion behaviour of the coatings in molten uranium was studied by using differential thermal analysis (DTA) up to 1473 K. The results showed that the coatings offered sufficient protection to graphite against corrosion by molten uranium.