Development and Evaluation of Processes for Deposition of Ni/Co-Cr-Aly (MCrAly) Coatings for Gas Turbine Components.
Abstract
The application of MCrAlY (M = Ni or Co or Ni + Co) coatings to high-temperature turbine blades and vanes is primarily provided by the electron beam, physical vapor deposition (PVD) process. Two major drawbacks of the PVD MCrAlY coating are high cost and line-of-sight (LOS) limitation. The controlled composition reaction sintered (CCRS) MCrAlY process was developed as a cost-effective, non-LOS alternative to the PVD coating process. The objective of this program were to develop the non-LOS technique for coating complex clustered airfoil configurations and to extensively test and evaluate the mechanical, thermal shock and environmental properties of the CCRS CoNiCrAlY coating relative to commercially available PVD NiCrAlY, PVD CoCrAlY and CODEP B coatings. The CCRS process can be either LOS or non-LOS, depending on part geometry. The former consists of slurry spraying the CoNiCrAlY powder onto the cleaned part followed by reaction sintering in a controlled activity aluminized pack. The latter utilizes an electrophoretic plus fluidized bed (E/FB) approach to deposit the CoNiCrY bisque prior to aluminization. When applied to nickel-base alloys (Rene' 125 and MA754) full densification of the CoNiCrAlY coating was achieved; however, the coating had greater porosity on cobalt-base X-40 alloy. The nominal composition of CCRS CoNiCrAlY on Rene' 125 and X-40 are Co(bal)/33-42Ni/6-10Cr/12-19Al/Y and Co(bal)/18Ni/10-20Cr/14-16Al/Y, respectively.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1979
- Accession Number
- ADA085197
Entities
People
- A. R. Stetson
- L. Hsu
- W. G. Stevens