Abstract
This paper investigates the electrochemical discharge machining (ECDM) mechanism to address the susceptibility of coatings to cracking, delamination, microcracks, and recast layers during the machining of film cooling holes with thermal barrier coatings. By using NaOH as the working fluid and enhancing chip removal through electrode rotation, this study investigates the machining state transition laws, material removal mechanisms, and post-processing workpiece surface integrity in ECDM of film cooling holes with thermal barrier coatings. The results indicate that only the electrochemical discharge effect is active during the ECDM of the ceramic layer, with material removal primarily dependent on rapid thermal cycling and electrochemical discharge. In contrast, for metal substrates, both electrochemical and electrical discharge machining occur, involving electrochemical and thermal effects. This study provides valuable insights for the efficient and high-quality production of film cooling holes with thermal barrier coatings.