Oxidation of MCrAlY coatings on Ni based superalloys

Interdiffusion Behavior of Pt-Diffused γ+γ' Coatings on Ni-Based Superalloys

Platinum-diffused γ+γ' coatings (~20 at.% Al, ~22 at.% Pt) were synthesized on René 142 and René N5 Ni-based superalloys by electroplating the substrates with ~7 μm of Pt, followed by an annealing treatment in vacuum at 1175°C. In order to study the compositional and microstructural evolution of these coatings at elevated temperatures, interdiffusion experiments were carried out on coated speci...

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

Effect of Surface Morphologies on the Isothermal Oxidation Behavior of MCrAlY Coatings Fabricated by High-velocity Oxyfuel Processes

In this study, the effect of surface morphologies on the isothermal oxidation behavior of MCrAlY coatings fabricated by high-velocity oxyfuel (HVOF) processes was investigated. To do so, free standing coatings with as-sprayed and polished surfaces were isothermally oxidized at 1050°C. The thickness of the bond coat was approximately 380μm. The Ra of the as-sprayed and polished surfaces were 6.4...

Modeling of the microstructural evolution and lifetime prediction of MCrAlX coatings on Nickel based superalloys in high temperature oxidation

MCrAlY coatings are deposited onto superalloys to provide oxidation and corrosion protection at high temperature by the formation of a thermally grown oxide scale. In this project, the oxidation behaviour of a HVOF CoNiCrAlYSi coating on IN792 was studied for both isothermal oxidation (900, 1000 and 1100 °C) and thermal cycling (100-1100 °C). The microstructural evolution of the CoNiCrAlYSi coa...

ON THE FORMATION OF STRAY GRAINS IN DIRECTIONALLY-SOLIDIFIED NI-BASED SUPERALLOYS WITH VARYING CROSS SECTIONS

Formation of stray grain defects particularly around re-entrant features of the turbine blade airfoils is one of the major problems in directional and single crystal solidification processes. In this work, directional solidification tests of the GTD-111 Ni-based superalloy were conducted at different withdrawal velocities of 3, 6 and 9 mm.min-1 using various stepped cylindrical and cubic design...