1997 Volume 15 Issue 4 Pages 657-663
The low-pressure plasma spray coating process has been established in gas turbine and is used for some parts, such as turbine blades and duct segments, which are exposed to corrosive gases at high temperatures. Overlay coatings based on the MCrA1Y alloy system (M is Ni and/or Co) are commonly employed as oxidation- and corrosion-resistant coatings. Mechanical properties, such as short-time tensile strength and creep-rupture lives, of CoCrA1Y- and CoNiCrAlY-coated systems were investigated at high temperature and compared with the uncoated substrates, such as equiaxis IN738LC, directional solidified CM247LC and single-crystal CMSX-2. As a result, it was clarified that MCrAIY coatings had no significant influence on the tensile strength and creep lives at high temperature. However, the tensile strength at room temperature was reduced for the low-ductility of MCrAlY coatings.
