Microstructure and positron lifetimes of zirconium modified aluminide coatings

The microstructure of the palladium modified and non-modified aluminide coatings was examined by the EDS and the positron annihilation spectroscopy methods. Both coatings have a double layer structure: β-NiAl phase or β-(Ni,Pd)Al phase on the top and the interdiffusion zones with the chromium and molybdenum rich phases in the β-NiAl or or β-(Ni,Pd)Al phase below. Palladium, that forms the β-(Ni,Pd)Al phase and substitutes for nickel atoms causes the increase of the positron lifetime value due to the increase in the number of open volume defects in the lattice which are jogs or vacancies on dislocation lines.

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Electronic structure calculations of positron lifetimes in nuclear materials: SiC and UO2

SNA + MC 2013 - Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo ◽

10.1051/snamc/201401312 ◽

2014 ◽

Author(s):

Julia Wiktor ◽

Gérald Jomard ◽

Michel Freyss ◽

Marjorie Bertolus

Keyword(s):

Electronic Structure ◽

Electronic Structure Calculations ◽

Nuclear Materials ◽

Positron Lifetimes ◽

Structure Calculations

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An inverse method for determination of the interdiffusivity in aluminide coatings formed on superalloy

Surface and Coatings Technology ◽

10.1016/s0257-8972(03)00879-x ◽

2004 ◽

Vol 182 (1) ◽

pp. 112-116 ◽

Cited By ~ 7

Author(s):

Hua Wei ◽

Xiaofeng Sun ◽

Qi Zheng ◽

Guichen Hou ◽

Hengrong Guan ◽

...

Keyword(s):

Inverse Method ◽

Aluminide Coatings

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Study of the Role of Small Additions of Zr in the CVD- FBR Aluminization Process

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.289-292.293 ◽

2009 ◽

Vol 289-292 ◽

pp. 293-300

Author(s):

L. Sánchez ◽

F.J. Bolívar ◽

M.P. Hierro ◽

F.J. Pérez

Keyword(s):

Fluidized Bed ◽

Vapor Deposition ◽

Chemical Vapor ◽

Fluidized Bed Reactor ◽

Iron Aluminide ◽

Martensitic Steels ◽

Aluminide Coatings ◽

Deposition Parameters ◽

Zirconium Powder

In this work, iron aluminide coatings were developed by Chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) on ferritic-martensitic steels. Small additions of zirconium powder were introduced in the fluidized bed; as a consequence, the obtained coatings are thicker than that without zirconium additions. When Zr powders are added in the fluidized bed, the deposition atmosphere drastically changes, leading to increase the deposition rate. Thermodynamic calculations were carried out to simulate the modifications in the CVD atmosphere in the Al/Zr deposition system in comparison to the single aluminization. In order to optimize the conditions of the deposition, parameters such as temperature and concentration of zirconium introduced into the bed were evaluated and compared with the results obtained for the single aluminum deposition.

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