Investigation of the microstructure of platinum-modified aluminide coatings

Abstract The high temperature performance of Pt-modified aluminide coatings is directly related to their composition and microstructure. In this work, several of the factors that control such features are investigated on a single crystal Ni base superalloy. It will be shown that the bi-phase PtAl2+(Ni,Pt)Al composition is more prone to occur at higher Pt surface concentrations, lower temperatures and shorter aluminising treatments. The alloying elements also seem to play a role in the achievement of either a single or a bi-phase structure. Finally, the incorporation of different elements to the Pt/Al coatings brings about shifting of the X-ray peaks, which in turn may indicate the presence of residual stresses.

[1]  S. Joshi,et al.  Role of Pt content in the microstructural development and oxidation performance of Pt–aluminide coatings produced using a high-activity aluminizing process , 1998 .

[2]  P. K. Datta,et al.  An assessment of the oxidation resistance of an iridium and an iridium/platinum low-activity aluminide/MarM002 system at 1100°C , 1999 .

[3]  D. H. Boone,et al.  Structure and hot corrosion behavior of platinum-modified aluminide coatings , 1987 .

[4]  K. Stiller,et al.  Comparison of inward and outward grown Pt modified aluminide diffusion coatings on a Ni based single crystal superalloy , 2002 .

[5]  I. Wright,et al.  Characterization of commercial EB-PVD TBC systems with CVD (Ni,Pt)Al bond coatings , 2001 .

[6]  J. Chen,et al.  Degradation of the platinum aluminide coating on CMSX4 at 1100 °C , 1997 .

[7]  N. Dahotre,et al.  Elevated Temperature Coatings: Science and Technology IV , 2001 .

[8]  P. Wright,et al.  Microstructural evolution of platinum modified nickel aluminide bond coat during thermal cycling , 2003 .

[9]  R. Reed,et al.  The precipitation of topologically close-packed phases in rhenium-containing superalloys , 2001 .

[10]  David R. Clarke,et al.  Surface rumpling of a (Ni, Pt)Al bond coat induced by cyclic oxidation , 2000 .

[11]  D. Arrell,et al.  Evolution of a PtAl2 coating on the nickel-base alloy CMSX-6 subjected to thermo-mechanical fatigue , 1999 .

[12]  M. R. Jackson,et al.  The aluminization of platinum and platinum-coated IN-738 , 1977 .

[13]  S. Joshi,et al.  Effect of prealuminizing diffusion treatment on microstructural evolution of high-activity pt-aluminide coatings , 2000 .

[14]  H. M. Tawancy,et al.  Comparative thermal stability characteristics and isothermal oxidation behavior of an aluminized and a Pt-aluminized Ni-base superalloy , 1995 .

[15]  A. Evans,et al.  Measurement of the residual stress in a Pt-aluminide bond coat , 2002 .

[16]  N. N. Greenwood,et al.  Chemistry of the elements , 1984 .

[17]  T. Girardeau,et al.  Study by complementary X-ray techniques of in-depth microstructure in Ni-based superalloys after Pt diffusion treatment , 2002 .

[18]  A. Karlsson,et al.  On the microstructural development in platinum-modified nickel-aluminide bond coats , 2004 .

[19]  R. Reed,et al.  Interdiffusion of the platinum-group metals in nickel at elevated temperatures , 2003 .

[20]  K. Stiller,et al.  A comparative study of two inward grown Pt modified Al diffusion coatings on a single crystal Ni base superalloy , 2001 .

[21]  D. H. Boone,et al.  Mechanical degradation of coating systems in high-temperature cyclic oxidation , 1995 .

[22]  Woo Y. Lee,et al.  Martensitic transformation in CVD NiAl and (Ni,Pt)Al bond coatings , 2003 .

[23]  Brace M. Warnes,et al.  Clean diffusion coatings by chemical vapor deposition , 1997 .

[24]  G. Lehnert,et al.  A new protective coating for nickel alloys , 1973 .

[25]  P. Shen,et al.  Microstructures of two-stage aluminized coatings on Inconel 600 , 1996 .