Cyclic oxidation behavior and microstructure evolution of aluminized, Pt-aluminized high velocity oxygen fuel sprayed CoNiCrAlY coatings

Combating Corrosion Degradation of Turbine Materials Using HVOF Sprayed 25% (Cr3C2-25(Ni20Cr)) + NiCrAlY Coating

“…Hot corrosion has become a major degradation mechanism (solid salt deposit on the component Type I hot corrosion) in turbines which are operated with low grade fossil fuels [4][5][6]. To protect the components from degradation and to prolong their life, coatings are commonly used on the blades and vanes of gas turbines [7].…”

Microcracks Characterization for Thermal Barrier Coatings at High Temperature

“…Many attempts have been made to suppress the TGO growth during high-temperature thermal cycle. 20 The morphologies and EDS results of N1ÀN3 maintained at 1000 C for 240 min are displayed in Fig. 2 and Table 2.…”

The effect of the MCrAlY composition and aluminizing cycle upon the microstructure and hot corrosion resistance of the over‐aluminized MCrAlY coating on IN738LC alloy substrate

“…[1] Multilayer coating systems such as over-aluminized MCrAlY coatings have already been developed to address these surface-related problems by providing more amounts of aluminum on the surface of the components to protect them from hightemperature oxidation. [2][3][4][5][6][7][8][9][10] In fact, over-aluminizing the MCrAlY coating is somewhat different from the ordinary aluminizing of Ni-based superalloys via one of the available commercial pack aluminizing processes. The main difference is that MCrAlY coatings typically have their own aluminum content of 8−12 wt.% [10] (in contrast to less than 6 wt.% Al in Ni-based superalloys), which determines the alumina former (Ni/Co)Al beta phase content of the coating.…”

“…Merging the aluminizing treatment with the standard heat treatment cycles of the substrate alloy (for instance, 2 h solutionizing at 1120°C and 24 h aging at 845°C for IN738LC) or the diffusion bonding of the MCrAlY coating (2 h at more than 1100°C) would be another incentive for the involved industries in terms of consuming less energy and labor. Previous studies on the subject of MCrAlY overaluminizing are rare, [2][3][4][5][6][7][8][9][10] most of which employed costly low-pressure plasma spraying to deposit the MCrAlY, while only the current research group considered the aluminizing treatment as a variable. [9] In the current investigation, one-and two-step aluminizing treatments have been examined on high-velocity oxy-fuel (HVOF) sprayed MCrAlY coatings using two feed powders of different nickel/cobalt ratios to optimize the coating microstructure for better resistance against high-temperature degradation mechanisms.…”