Comparison of the isothermal oxidation resistance of HVOF, VPS and APS CoNiCrAlY coatings sprayed onto Inconel 738 Nickel superalloy

摘要

Commercial CoNiCrAlY powders with the same chemical composition were sprayed by vacuum plasma spraying (VPS), air plasma spraying (APS) and high velocity oxy gen-fuel (HVOF) onto Inconel 738 superalloy substrates obtaining coatings of com parable thickness. Samples were oxidized at 1000°C up to 3000 hours. The high temperature oxidation behaviour of the three different sample types was studied by means of morphological, microstructural and compositional analyses. HVOF tech nique can provide bond coats with higher oxidation resistance compared to APS and VPS and can represent an effective alternative to the latter spraying technique.