Role of process conditions on the interfacial fracture toughness of plasma sprayed zirconia

Adhesive property of the plasma-sprayed thermal barrier coating (TBC) is

  one of the most important parameters which influence the reliability

  during service. In the past, numerous test methods are reported to

  measure the coating adhesion. However, most of them require careful and

  time consuming preparation. Consequently, there is limited information to

  establish the relationship between spray conditions and adhesive

  property. To produce more results using a simpler procedure, the

  interfacial indentation test and the standardized tensile adhesive test

  are examined. In this paper, the interfacial fracture toughness of the

  plasma-sprayed ZrO2 coatings, deposited on Al substrates, were evaluated

  by these two tests. In order to study the effect of the powder injection,

  samples were sprayed for various carrier gas flow rate. The test results

  show the correlation between the Melting Index and the interfacial

  fracture toughness. In addition, correlations between the results

  obtained from two different methods are discussed.