Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

Abstract

The purpose of this research is to look into the effect of laser surface modification on the hot corrosion and hot corrosion + calcium–magnesium aluminosilicate (CMAS) resistance of YSZ thermal barrier coating. Metco AMDRY 997 (Ni–22Cr–10Al–Y) powder was coated as a bond coat on the AISI 304L stainless steel substrate using a high-velocity oxy-fuel spray technique. As a ceramic top layer, 204 NS YSZ (ZrO2·8Y2O3) particles were plasma sprayed on the bond coat. Following that, the entire coating surface was treated with a 20-kHz pulsed CO2 laser to increase the coatings’ surface performance. A corrosion test was carried out in a box furnace for 20 h at 1050 °C. SEM images of laser-glazed coatings revealed denser surfaces than those of air-spraying coatings. The laser-modified coating is more resistant to hot corrosion than unmodified coatings. The X-ray diffraction analysis revealed that the reaction between yttria (Y2O3) and V2O5 resulted in the formation of YVO4 crystals as a corrosion product. According to energy dispersive spectroscopy results, laser-glazed coatings reduced molten salt diffusion from surface to bond coat. As a result, laser-glazed coatings demonstrated improved hot corrosion resistance and decreased corrosion products on the bond coat zone. After the hot corrosion test, the laser-treated composite had a 55% lower thermally grown oxide layer than untreated APS YSZ. The optimum laser parameter was used as 77.7 W laser power, 120 mm/s scanning speed, and 215 mm laser distance.

WITHDRAWN: Hot Corrosion Evaluation of Cr 3 C 2 /8YSZ based Plasma Sprayed Coatings on SS316 in Na 2 SO 4 – V 2 O 5 Molten Salt Environment at 700 0 C

“…Coatings made of YSZ were shown to be the most effective coatings in thermal barrier characteristics of gas turbine blades, and their hot corrosion behaviour on superalloys in hot gas environments has been reported in the previous work [21][22][23][24][25][26]. The study conducted by Avci et al [27] examined the effectiveness of YSZ coating in preventing corrosion at high temperatures. Yttrium vanadate (YVO 4 ) was found to be generated as a result of the interaction between yttria and vanadium pentoxide (V 2 O 5 ) at high temperature conditions.…”

CMAS Corrosion Behavior of Nanostructured YSZ and Gd-Yb-Y-Stabilized Zirconia Coatings

“…fifth, optimization treatments on the surface of the ceramic coatings, such as reducing the surface roughness of coatings [29], laser modification [30], and creating micro-nano double-scale structure [31].…”

“…To find and develop coatings with improved resistance to CMAS corrosion, research institutes have focused substantial research in the following directions: first, developing novel ceramic coating materials, such as RE 2 Zr 2 O 7 [13][14][15], REPO 3 [16], Ti 2 AlC [17], and Hf 6 Ta 2 O 17 [18]; second, doping YSZ with oxides, including rare earth oxide-doped YSZ [19,20] and Al-and Ti-doped YSZ [21][22][23]; third, depositing protective layers on the surface of the coatings, such as the Pt layer [24] and Al 2 O 3 layer [25]; fourth, designing dual-layer ceramic coating structures, such as Gd 2 Zr 2 O 7 /YSZ [26,27] and La 2 Ce 2 O 7 /YSZ [28]; fifth, optimization treatments on the surface of the ceramic coatings, such as reducing the surface roughness of coatings [29], laser modification [30], and creating micro-nano double-scale structure [31].…”