Thermal shock behavior of nanostructured and microstructured thermal barrier coatings on a Fe-based alloy

Comparison of Thermal Shock Behavior of 7ysz, 15ysz and Sysz Thermal Barrier Coatings Produced by Aps Method

“…In the current work, after thermal cycles, vertical and propagating or horizontal crack emerged in the SYSZ and YSZ top coat (Figure 7). However, no obvious oxide and the penetrating crack were generated at the bond coat and the substrate interface, in contrast to what was formed in Li work [23] on thermal failure of nanostructured TBCs.…”

“…Therefore, analysis of weight changes ( Figure 6) and microscopic images (Figure 7) showed that the failure of the three nanostructured coatings was in a similar mode, occurring as spallation of the top coat, near and parallel to the top coat/bond coat interface. Research shows that after thermal shock tests, four types of cracks were formed in the TBCs, namely, vertical cracks, horizontal cracks, propagating cracks, and penetrating cracks [23]. In penetrating cracks, vertical cracks penetrate the bond coat to the substrate surface.…”

“…Δα is the difference in CTE between the ceramic coating and the metallic substrate, and ΔT is the change in temperatures. [3,23], respectively. By taking Poisson ratio and elastic modulus value equal to 0.12 and 26 GPa, the thermal expansion mismatch stress value (σ c ) of 7YSZ, SYSZ and 15YSZ was obtained to be 0.142 GPa, -0.147 GPa and -0.170 GPa, respectively.…”

“…In recent years, nanostructured zirconia based TBCs deposited by atmospheric plasma spraying have been the focus of attention. It was reported that nanostructured thermal barrier coatings had high bonding strength [20], low thermal conductivity [20][21][22][23][24], and prolonged thermal cycling lifetime [25][26][27]. Accordingly, nanostructured TBCs are expected to provide better performance than the conventional TBCs.…”

Thermal stability and sintering behavior of plasma sprayed nanostructured 7YSZ, 15YSZ and 5.5SYSZ coatings at elevated temperatures

“…In recent years, nanostructured zirconia based TBCs have been the focus of devotion. The advantages of the nano-to micro-TBCs include high bonding strength [20], low thermal conductivity [20][21][22][23][24], and prolonged thermal cycling lifetime [25][26][27].…”