Synthesis of clean aluminide coatings on Ni‐based superalloys via a modified pack cementation process

Abstract

With the aim of seeking a modified pack cementation process as a potential low‐cost alternative to form clean and reproducible aluminide coatings for laboratory diffusion coating research, four non‐contact arrangements were employed to coat Ni‐based superalloy specimens. The advantages and disadvantages of each arrangement were discussed by comparing the cleanliness of coating surface, the homogeneity of surface Al content and coating thickness, as well as the easiness of preparation. By utilizing the arrangement with the best overall quality, an Ni‐rich β‐NiAl coating with a clean surface and a low S level (0.3 ppmw) was achieved, which was comparable to the coatings previously made by an ultra‐clean laboratory chemical vapor deposition (CVD) process. Reactive element (RE) additions such as Hf, Zr, or Y were codeposited by including a small amount of the respective RE oxide in the pack mixture, and approximately 500 ppmw Hf was detected in the Hf‐modified NiAl coating.

Cyclic oxidation behavior of MCrAlX coatings made by electrolytic codeposition

“…Depth profiles were constructed based on the average sputtering rate and the sputtering time. [ 24–26 ]…”

904L Paslanmaz Çeliğe Düşük Sıcaklık Alüminyumlamanın Etkisi

“…There are various aluminizing techniques such as chemical vapor deposition, physical vapor deposition, hot-dip aluminizing, or pack cementation (Priest and Zhang, 2015). Pack cementation has a low cost and simple technique compared to others.…”

Heat-Resisting Aluminized Coatings Modified by Chromium Addition Produced on Nickel-Based Alloys

“…Al 2 O 3 coating on the surface, provides the appropriate heat resistance [6,7] and can be used for various materials. Such coatings are formed on TiAl alloys [8], austenitic steel [9], Co-based superalloy [10,11] or aforementioned Ni-based alloys [7]. It is also possible to produce these coatings on alloys such as Fe-30Cr and impure metals such as Fe, Ni or Mo [12].…”