A relationship of porosity and mechanical properties of spark plasma sintered scandia stabilized zirconia thermal barrier coating

A Comprehensive Understanding of Thermal Barrier Coatings (TBCs): Applications, Materials, Coating Design and Failure Mechanisms

“…SPS's adaptability, influenced by spray parameters and the formulation of the suspension, enables it to produce coatings with a wide range of porosities. This includes achieving highly porous coatings beyond what APS or EB-PVD typically offer, even over 50% [176]. Remarkably, SPS can create columnar structures, similar to EB-PVD or cauliflower-like structures, providing enhanced strain tolerance and better thermal fatigue strength than coatings applied via APS [177][178][179].…”

“…They used micrometric particles (<10 µm) to produce 100 µm thick coatings with about 8% porosity and nanometric particles (<1 µm) to achieve 40 µm thick coatings with 16% porosity. Using 7-8YSZ particles ranging from 50 to 150 nm, Gao et al [181] achieved with APS a thermal conductivity of 0.8-0.95 Wm −1 K −1 across temperatures of 300-450 • C. achieving highly porous coatings beyond what APS or EB-PVD typically offer, even over 50% [176]. Remarkably, SPS can create columnar structures, similar to EB-PVD or cauliflower-like structures, providing enhanced strain tolerance and better thermal fatigue strength than coatings applied via APS [177][178][179].…”

“…For porosities exceeding 20%, poor erosion resistance has been reported, with high-porosity TBCs having more limited use [184]. On the other hand, thermal conductivity can be reduced to as low as 0.4 Wm −1 K −1 when the porosity level is increased beyond 30% [176].…”