|
1252 |
|
Effect of the increase in the entrance convergent section length and geometry of the gun nozzle on properties of cold sprayed copper and titanium coatings |
|
Kazuhiko Sakaki* / SHINSHU University, Japan Muneaki Takahata / Graduate School?CShinshu University, Japan Kazuya Takeda/ Graduate School?CShinshu University, Japan Shuhei Shinkai/ DENSO Corporation, Japan Takashi Hosono/ Shinshu University, Japan Yasuo Shimizu/ Shinshu University, Japan |
|
Nozzle geometry, which influences gas dynamics and, therefore, sprayed particle behavior is one of the most important parameters in cold spray process. The gas flows in the entrance convergent section of the nozzle exhibit a relatively higher temperature and are subsonic; thus; this region is most suitable for heating spray particle. In this study, numerical simulation and experiments investigated the effect of the nozzle contour (convergent ?NCdivergent and convergent-divergent-barrel), entrance geometry of convergent ?NCdivergent nozzle and powder injection position at nozzle on the cold spray process. The process changes inside the nozzle as obtained by numerical simulation studies were related to the coating properties. A titanium and copper powder was used for the experimental studies. Working gas (is nitrogen) pressure and temperature at nozzle-intake were 3MPa and 350©bC. The change in the nozzle and contour entrance convergent section length of the gun nozzle had a significant effect on the deposition efficiency and microstructure. The deposition efficiency increased as this geometry increased. Numerical simulation and experiments investigated the influence of two nozzle contour, entarance geometry and powder injection position of nozzle on the cold spray process. The process changes inside the nozzle as obtained by numerical simulation studies were related to the coating properties. A titanium and copper powder was used for this study. |