TITLE:
Hot Corrosion Behaviour of Yttria-Stabilised Zirconia as Plasma Sprayed Coated Boiler Steel in Air and Salt at 900°C under Cyclic Condition
AUTHORS:
Dinesh Gond, D. Puri, S. Prakash
KEYWORDS:
Hot corrosion; T-22; Plasma spray coating.
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.10 No.5,
April
20,
2011
ABSTRACT: Yttria-Stabilised Zirconia (YSZ) coatings were deposited on a T-22 boiler steel. NiCrAlY was
used as bond coat and YSZ as top coat. Hot corrosion studies were conducted on uncoated as
well as plasma spray coated specimens in air as well as salt (75 wt.% Na2SO4 + 25 wt.% NaCl) at 900°C under cyclic conditions. The thermogravimetric technique was used to establish kinetics of corrosion. X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive x-ray analysis (SEM/EDAX) techniques were used to analyse the corrosion products. This YSZ overlay coatings enhance resistance to corrosion
significantly which can be attributed to formation of zirconium oxides (ZrO2) and yttrium oxide (Y2O3). This coating was more effective in salt environment and there is an extra phase of ZrS.