High temperature characteristics of Ir-Ta coated and aluminized Ni-base single crystal superalloys

High temperature oxidation and hot corrosion properties of Ir-Ta coated and aluminized Ni-base superalloys are presented. An Ir-Ta binary alloy, proposed as a novel metallic bond coat material, was coated on a Ni-base single crystal superalloy TMS-75 using electron beam physical vapor deposition, followed by a conventional low activity Al pack cementation process. Cyclic oxidation tests and hot corrosion tests revealed that these Ir-Ta coated and aluminized specimens showed reasonably good oxidation and hot corrosion resistance. In addition, it was found that the fort-nation of TCP phases is suppressed by the presence of the Ir-Ta enriched layer. These results indicated that the Ir-Ta alloy system is promising as a new metallic bond coat material for high temperature structural materials. (C) 2004 Elsevier Ltd. All rights reserved.