Hot corrosion studies on plasma sprayed bi-layered YSZ/La 2 Ce 2 O 7 thermal barrier coating fabricated from synthesized powders

Improved hot corrosion resistance of plasma sprayed YSZ/Gd2Zr2O7 thermal barrier coating over single layer YSZ

“…Unlike the SPS GZO/YSZ TBCs [12], the present study illustrates that the plasma sprayed bilayer coating without columnar microstructure is a better option to design a TBC with improved hot corrosion resistance. Furthermore, the hot corrosion properties of YSZ/La 2 Ce 2 O 7 (LCO) bilayer TBCs have been studied in our previous work [26].In comparison to YSZ/LCO bilayer TBCs, the YSZ/GZO coatings exhibited better corrosion resistance properties. The weight gain results of YSZ and bilayer YSZ/GDZ coatings exposed to 1100 °C thermal cycling revealed higher weight gain for YSZ single layer TBCs.…”

“…Plasma grade flowable 8 wt% YSZ and GZO powders were prepared by a single step co-precipitation technique. The detailed experimental procedure for the synthesis of flowable 8 wt% YSZ powders has already been described in our previous work [26]. The steps involved in the preparation of GZO powders are as follows: gadolinium nitrate solution was prepared by adding dilute nitric acid to 50 g of Gd 2 O 3 powder (99.9% purity, Mincometsal).…”

“…The bond coat material used is AMDRY 962 (Sulzer Metco) with the composition Al-9.07 wt%, Cr-23.22 wt%, Ni-67.39 wt% and Y-0.33 wt%. Details of the substrates used for the fabrication of all the coatings has been reported in our previous work [26]. Table 1 shows the optimized plasma spray parameters employed for the fabrication of all the coatings.…”

“…Hot corrosion tests on the fabricated coatings (4 samples each of YSZ and YSZ/GZO) were conducted using mixture of 55 wt% of sodium sulphate (Na 2 SO 4 , Loba chemie, 99% purity) and 45 wt% vanadium pentoxide (V 2 O 5 , Loba chemie, 99% purity) salts. The surface of the coatings was coated manually by the corrosive salt mixture such that the concentration of salt is 25 mg/cm 2 [26]. The samples were kept in a muffle furnace at 910 °C in air atmosphere.…”

Structural investigation of Al2O3 coatings by PECVD with a high deposition rate

“…However, there are disadvantages such as excoriation, hot corrosion, and phase transition, which reduce the service life of the coating . Hot corrosion is one of the main damage factors in thermal barrier coatings due to the effect of molten salts on the coating‐gas interface . Transport fuels usually contain sundries such as Na and V, leading to the formation of Na 2 SO 4 and V 2 O 5 salts on the surface of turbine blades .…”