Fig 1.
SEM photo of the cross section of a representative as-sprayed DCL-TBCs.
Thicknesses of LZ layer, YSZ layer, BC and substrate are 220±20μm, 110±20μm, 65±20μm and 3±0.1mm, respectively. BC is fabricated by High-Velocity Oxygen-Fuel (HVOF) method, YSZ and LZ layers are fabricated by APS method.
Fig 2.
Schematic diagram of the whole fabrication process of DCL-TBCs.
Fig 3.
Schematic of the “YSZ+BC+substrate” combination thermal deformation during the pre-heating process.
(A) This combination is preheated from room temperature to a given temperature (e.g. 500°C). (B) From state “a” to “c”: before the pre-heating process of the “YSZ+BC+substrate” combination, constraint-free thermal deformation without interaction between different layers, and the end of the pre-heating process of “YSZ+BC+substrate” combination.
Fig 4.
Schematic of “LZ+YSZ+BC+substrate” combination thermal deformation in the process of DCL-TBCs cools to room temperature.
From state “a” to “c” (from top to bottom): the beginning of the “LZ+YSZ+BC+substrate” combination cooling down process, constraint-free thermal deformation, and the end of “LZ+YSZ+BC+substrate” combination cooling down process.
Table 1.
Fig 5.
Mesh of FEM simulation.
Fig 6.
Residual stress generated in step 1~5 by FEM simulation.
Fig 7.
Comparison of residual stress generated during step 1~5 by theoretical model and FEM.
Fig 8.
Final/Total residual stress generated in the whole fabrication process of DCL-TBCs.
Fig 9.
Comparison of final residual stress generated in the fabrication of DCL-TBCs with different pre-heating temperatures.
Different pre-heating temperatures are: i.e. 23°C, 250°C, 500°C, 1000°C.
Fig 10.
Comparison of final residual stress generated with different thickness ratios of YSZ to LZ layers.
(A) Different thickness ratios of YSZ to LZ layers are: i.e. YSZ: 250μm, LZ: 50μm; YSZ: 200μm, LZ: 100μm; YSZ: 150μm, LZ: 150μm; YSZ: 100μm, LZ: 200μm; and YSZ: 50μm, LZ: 250μm. (B) (a-c) respect residual stress generated in LZ layer, YSZ layer and the combination of “substrate + BC”, respectively.