TITLE:
Rheological Behaviour, Synthesis and Performance of Smart Thermal Barrier Coating Systems Based on Hollow Alumina
AUTHORS:
F. Pedraza, B. Rannou, G. Boissonnet, B. Bouchaud, Z. Maache-Rezzoug
KEYWORDS:
Slurry, Viscosity, Wetting, Thermal Barrier Coating, Thermal Conductivity, Oxidation
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.3 No.12,
December
17,
2015
ABSTRACT: The stability of three water-based slurries
containing different loads of Al microparticles was measured by laser scattering.
The slurries displayed a Newtonian behaviour and the evolution of viscosity
over nine days was found to be constant. Ground surfaces of nickel were also
wetted similarly irrespective of the Al content in the slurries (30, 40 or 50
wt%) thereby demonstrating that the 1/10 PVA/H2O water based slurries are
adequate for spraying. After deposition and annealing of the as-sprayed
coatings, a thermal barrier coating system was formed with a top coat of hollow
alumina spheres, an intermediate thermally grown oxide and a bottom aluminized
bond coat. The coating system is shown to display very low thermal conductivity
and remarkable oxidation resistance at high temperatures.