The residual stresses in manganese cobaltite, i.e., Mn_(1.5)Co_(1.5)O_4 , coatings applied onto alloys 441 and Crofer 22 APU were determined by X-Ray Diffraction. The residual stresses were found to be tensile at 800°C for both systems. The residual stress for spinel-coated AL441 relaxed with time and reached a value of 0.16±0.02 GPa after 300 minutes. The stress relaxation process was slower for spinel-coated Crofer and reached a value of 0.23±0.01 GPa after 500 minutes.Four-point bend SENB testing technique was used to evaluate the toughness of the interfaces between LSM10, i.e., (La_(0.9)Sr_(0.1) )_(0.98)MnO_(3+?), and spinel-coated AL441 and Crofer. Sandwich test specimens were prepared by sintering the LSM10 layer at 900°C for four hours in air or under pO_2 cyclic conditions. The strain energy release rate was found to be 1.52±0.11 J/m~2 for regular sintering and 1.47 ± 0.15 J/m~2 for sintering with cyclic pO_2 treatment. This difference was found to be statistically insignificant.
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