Thermal Cycling of Suspension Plasma Sprayed Alumina‐YSZ Coatings Containing Amorphous Phases

Abstract

Thermal cyclic test at 1080°C for various numbers of cycles was performed on suspension plasma‐sprayed coatings of alumina‐yttria‐stabilized zirconia composites and yttria‐stabilized zirconia ( YSZ ). The structural variations of composite coatings were studied to verify the possibility of production of nano‐composite coatings with nano‐dispersed oxides. The results showed that this composite exhibited a lower thermally grown oxide growth than that of the YSZ . New multi‐constituent composites formed of alternative regions of nano‐precipitates of alumina in zirconia matrix and nano‐precipitates of zirconia in alumina matrix were developed via phase transformation through thermal cyclic process of amorphous‐containing structure.

Repressing high‐temperature radiative heat transfer in thermal barrier coatings

“…As corundum ( H = 15 GPa) 38 is harder than 8YSZ ( H = 13.3 ± 0.3 GPa in this study), it was expected that the composites hardness would be increased by the addition of corundum. The addition of alumina into zirconia increases the densification by changing the diffusion mechanism from grain boundary to volume diffusion and significantly decreases the activation energy, also the high‐temperature sintering causes internal sintering of the materials resulting in high hardness 40–42 . The corundum smaller particles size (0.2–0.4 μm, see Figure 4) more effectively refines the grain size and the grain boundaries of 8YSZ, thus hardness increases with decreasing particle size, this is known as the Hall–Petch effect.…”

“…The addition of alumina into zirconia increases the densification by changing the diffusion mechanism from grain boundary to volume diffusion and significantly decreases the activation energy, also the high-temperature sintering causes internal sintering of the materials resulting in high hardness. [40][41][42] The corundum smaller particles size (0.2-0.4 μm, see Figure 4) more effectively refines the grain size and the grain boundaries of 8YSZ, thus hardness increases with decreasing particle size, this is known as the Hall-Petch effect. However, as the corundum particles size increases, its number density gradually decreases which allows a small increase in 8YSZ grain size that contributes to hardness value degradation of the composites.…”

Effect of Vacuum Annealing on Microstructure and Hot-Salt Corrosion Behavior of CoNiCrAlY/YSZ/LaMgAl11O19 Double-Ceramic Coating

“…Currently, LaMgAl 11 O 19 (LMA) is the most widely studied rare-earth hexaaluminate. It was found that a YSZ/LMA double-ceramic structure had a longer service life than a single-layer YSZ or LMA during thermal cycling tests [24][25][26][27][28]. Additionally, the YSZ/LMA double-ceramic structure exhibited better corrosion resistance to molten salts such as V 2 O 5 , Na 2 SO 4 + V 2 O 5 , and CAMS [29][30][31][32][33].…”

Photoluminescence study on irradiated yttria stabilized zirconia

“…Yttria (Y 2 O 3 ) stabilized zirconia (ZrO 2 , YSZ) is one of the most extensively studied oxide ceramic material, having numerous applications in the fields of bio-ceramics, fuel cells, sensors, nanomaterials, thermal/diffusion barrier coatings, and nuclear waste management [1][2][3][4][5][6][7][8][9][10][11][12]. In nuclear industry, cubic zirconia is considered as a potential inert host matrix for incineration of excess plutonium (Pu) [13][14][15][16][17][18] and transmutation of transuranic nuclear wastes [19][20][21][22].…”