|
2126 |
|
Monday, May 03, 2010, Sophia Room 3:00 PM Cold Spraying 2 |
|
Layer formation and impact phenomena of cold sprayed ceramic titanium dioxide particles on metal surfaces |
|
Jan-Oliver Kliemann* / Helmut-Schmidt-University of the Allied Forces, DE Christine Borchers/ University of Göttingen, Germany Julia Stötzner/ University of Hannover, Germany Henning Gutzmann/ Helmut-Schmidt-University, Germany Frank Gärtner/ Helmut-Schmidt-University, Germany Thomas Klassen/ Helmut-Schmidt-University, Germany |
|
In cold spraying, the required heat for bonding is provided by plastic deformation of the impacting ductile particles. Therefore, cold spraying is a well-established method for metal on metal coatings. However, few authors have investigated the impact phenomena and layer formation process for impacting brittle ceramic particles on ductile metal surfaces. For this study, TiO2 on metal surfaces was chosen as a model system, and layer formation on aluminum, copper, titanium and steel substrates was investigated by SEM, TEM, XRD and Raman spectroscopy. The results clearly show that the deposition efficiency depends of spray temperature, powder properties, and in particular of substrate ductility, even for an impact of ceramic particles during a second pass over already coated areas. High-resolution TEM images revealed no crystal growth or phase transitions at the ceramic/metal interfaces. Nevertheless, a clear dependence of the photocatalytic activity on spray parameters and substrate material could be observed. Cold-sprayed TiO2-coatings have potential applications in biomedical implants or as photo-catalytic functional systems. |