Abstract No.:
2817

 Scheduled at:
Tuesday, September 27, 2011, Saal B2.1 4:00 PM
Cold Spraying 2


 Title:
Chemical interaction and adhesion in cold gas spraying

 Authors:
Kerstin-Raffaela Ernst* / Helmut-Schmidt-University University of the Federal Armed Forces Hamburg Institute of Materials Technology, Germany
Frank Gärtner / Helmut-Schmidt-University, Institute of Materials Technology, Germany
Thomas Klassen/ Helmut-Schmidt-University, Institute of Materials Technology, Germany

 Abstract:
Cold gas spraying is widely used to build up metal-metal joinings. The bonding mechanism is well-understood and attributed to the occurrence of shear instabilities, which lead to welding and therefore strong metallic bonds in the interface. The bonding strength is influenced by the area of shear instabilities in contact to the substrate, by the hardness of the materials involved as well as the roughness of the surface. Up to now, chemical interactions were mainly neglected due to the small diffusion lengths during the short timescale of particle impact.

Expanding the spectra of material combinations, even to non-metallic compounds like ceramics, the explanation for bonding should take possible chemical interactions into account. In this respect, the effects of strong or weak chemical affinity between particle and substrate material as well as the effects of surface adsorbates have to be investigated.

In this presentation, combinations of different metals (Cu, Al) sprayed onto ceramics (Al2O3) and onto galvanized surfaces (Cr, Ni) will be used for a first approach to gain information about substrate-particle combinations with very different chemical affinities to discuss the possible effect of chemical interaction on the bond strength of cold sprayed coatings.


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