Metal dusting resistance

C. M. Chun, J. D. Mumford and T. A. Ramanarayanan, Metal Dusting Resistant Stable-Carbide Forming Alloy Surfaces, U.S. Patent Application Publication US2005/0170197 A1 (2005). 

Cr Improves oxidation resistance. Detrimental to nitriding and fluorination resistance Improves sulfidation resistance beneficial to carburization and metal dusting resistance... 

An attempt to protect the steels by preoxidation, i.e. heating up in H2/ 0.6%H20 had no clear effect only for the steel AISI 321 was the metal dusting resistance clearly improved. 

Improving metal dusting resistance of Ni-X alloys by an addition of Cu... 

The observation that Fe corrodes much faster than Ni in a metal dusting environment could be significant in the design of alloys for metal dusting resistance. Most alloys can be classified as Fe based, Ni based or Fe-Ni based. In what follows, the behavior of alloys in metal dusting environments is discussed, primarily based on experiments carried out by the authors. 

The excellent metal dusting resistance of high-Cr ferritic alloys can be attributed to the relatively higher Cr diffusivity in the ferritic bcc lattice which facilitates a protective Cr-rich oxide film to develop at Cr concentrations equal to or higher than about 20%. This observation has also been made by Grabke. However, for many stmctural applications, the mechanical properties of such steels may not be acceptable. 

Alloys with intrinsic metal dusting resistance... 

Ramanarayanan T A, Chun C, Mumford J D, Metal dusting resistant Cu-based alloy surfaces , US Patent 6,737,175, 18 May, 2004... 

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