Influence of salt spray corrosion on subsequent isothermal oxidation behaviours of AIP NiCoCrAlYSiB coatings

The influence of salt spray corrosion on subsequent oxidation behaviours of arc ion plated (AIP) NiCoCrAlYSiB coatings is investigated in this work. The results indicate impact of the salt spray corrosion on successive oxidation behaviour depends greatly on the degree of the previous corrosion attack. Accelerated oxidation kinetics and unsatisfactory oxide morphologies are observed on the as-deposited and as-annealed NiCoCrAlYSiB coatings that suffered serious salt spray attacks. Pre-oxidised coatings prove excellent performances during both salt spray tests and the subsequent oxidations. The mechanism of the corrosion attack influencing the isothermal oxidation behaviour is discussed.