Coatings sprayed at high-deposition rates often result in stiff, dense, and highly stressed coatings. The high deposition temperature at which the coatings are formed is responsible for these characteristics. In this paper, TBCs were sprayed at high-deposition rates, increasing the tensile quenching stresses beyond the threshold of crack opening during spraying. Dense structures were observed within a pass, in the presence of micro and macro defects specifically horizontal cracks within interpasses and vertical segmentation cracks. Mechanical properties, mainly the elastic and anelastic behavior of TBCs were significantly affected by the strain accommodation and friction occurring within intersplats and interpass interfaces. The strain tolerance obtained in as-sprayed conditions decreased as the microstructure and defects sintered during high-temperature heat cycles. The non-linearity degree decreased while the elastic modulus of the various coatings increased to a maximum value.
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The work was supported in part by National Science Foundation grant to Stony Brook University under award CMMI 1030942 which included an international collaboration supplement with the Czech Republic.
The authors acknowledge the support through the Stony Brook Industrial Consortium for Thermal Spray Technology, Oerlikon Metco, and Ron Molz for specimen preparation. This research was supported by Czech Ministry of Education, Youth and Sports through grant no. ME901 and Czech Science Foundation GACR P108/12/P552.
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