Abstract

Plasma sprayed thermal barriers are used as insulating materials in the hot sections of gas turbines to decrease the metal temperatures during service and men allow a higher combustion temperature for better engine efficiency. They usually contain a bond coating to protect the substrate from high temperature oxidation and a top coat with a low thermal conductivity. This study evaluate and identify the mechanisms of degradation of a vacuum plasma sprayed NiCoCrAlYTa bond coat subjected to thermal cycling at high temperature. The microstructure and micro-composition of the coating layer were analyzed by scanning electron microscopy and energy dispersive X-ray analysis to elucidate the improvement and degradation mechanisms of the material. The thermal cycling provokes some morphological and chemical modifications changes within this material. These modifications provoke a perturbation of the heat transfer within the material.

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