| Title |
The Influence of a Coating Treatment on the Creep Rupture Properties of a Nickel - Base Superalloy in an air and Corrosion Environment |
| Authors |
강석봉(Suck Bong Kang); 김학민(Hak Min Kim); 김영길(Young Gil Kim) |
| Abstract |
The effects of an aluminide coating treatment on creep-rupture properties of a nickel-base superalloy Rene´ 80 were investigated. It was found after creep tests at the ambient atmosphere that the coating treatment reduced rupture lives compared to the uncoated specimens. This is believed to be due to different crack formation mechanism between coated and uncoated specimens. For the uncoated specimens, creep crackings were initiated at the oxidized surfaces, while for the coated specimen, creep fractures were controlled by the crack unclei due to the high hardness of the diffusion zone in the coated layer. Some creep tests were also conducted on the coated and uncoated specimens at the hot corrosion environment of 75wtNa₂SO₄-25wt%NaCl. The improved creep life of the coated specimen especially obtained at 982℃/156.9MPa under conditions of the hot corrosion by a 75wt% Na₂SO₄25wt% NaCl was attributed to the ductile coating layer which flew readily into the widening crack region. |