| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1658549 | Surface and Coatings Technology | 2011 | 6 Pages |
NiCoCrAlY coatings were prepared on superalloy K417G using arc ion plating (AIP), then some specimens coated with NiCoCrAlY were aluminized using a pack cementation method. The high temperature oxidation and hot corrosion behavior of the ordinary and the aluminized NiCoCrAlY coatings were studied. The results indicated that α-Al2O3 scales grew on both coatings during oxidation at 1000 °C and 1100 °C in air, and the aluminized NiCoCrAlY coating always showed lower oxidation rates and lower degradation rates. The hot corrosion tests were carried out by applying salt films of 25 wt.% K2SO4 + 75 wt.% Na2SO4 mixture on the specimens and exposing in air at 900 °C. The aluminized NiCoCrAlY coating showed a longer lifetime by forming a continuous Al2O3 scale. But, cracks and spallation of the oxide scales occurred on the ordinary NiCoCrAlY coating after 80 h.
Research highlights► AIP NiCoCrAlY coating were modified by aluminizing using pack cementation process. ► Al2O3 scales formed on modified coatings during oxidation at both 1000 °C and 1100 °C. ► The modified coatings obtained a much longer lifetime during hot corrosion exposure.
