Abstract No.:

X-Ray micro-tomography and modeling of cold sprayed coated powders

Francesco Delloro* / Centre des matériaux, Ecole des Mines de Paris, France
Matthieu Faessel / MINES ParisTech (CMM), France
Michel Jeandin/ MINES ParisTech (CdM), France
Dominique Jeulin/ MINES ParisTech (CMM), France
Henri Proudhon/ MINES ParisTech (CdM), France
Sebastian Bucher/ LIFCO, France
Erick Meillot/ CEA Le Ripault, France
Luc Bianchi/ CEA Le Ripault, France

X-Ray Micro-Tomography (XMT) is more and more frequently used for microstructural characterization of materials in 3D. This imaging technique is based on local differences in X-ray absorption (i.e. chemical composition) within the sample. For the study of cold spray of tantalum onto copper, it is quite useful to treat images of single tantalum particles on copper, provided that these can be discriminated. To achieve an XMT image of a tantalum particle after the impact on already- deposited tantalum particles, it is necessary to overcome the fact that chemical homogeneity prevents the detection of the borders between particles. A solution in this sense is to promote a sufficient quantity of a contrasting outlining medium. It was first tried to deposit the medium on a polished cold sprayed tantalum layer by means of several techniques: thermal treatments to create an oxide layer at the Cu surface, electrolytic deposition, tape casting of copper and silver. Also, the deposition of iron onto the powder particles, by means of fluidized-bed CVD, is tried. The later was shown to be the best method. Experimental tests were coupled with finite element simulations of the impact of a spherical iron-coated particle.

<= go back