Plasma spray forming shows overwhelming advantages in rapid fabricating parts and moulds. The coating microstructure is strongly dependent on the splat morphology and inter-splat contact nature. Therefore,it is necess...Plasma spray forming shows overwhelming advantages in rapid fabricating parts and moulds. The coating microstructure is strongly dependent on the splat morphology and inter-splat contact nature. Therefore,it is necessary to investigate the splat formation mechanism in order to analyze the coating properties. A dynamical process of a single fully molten droplet impacting onto a smooth surface was investigated. At the same time,the interaction between the two molten droplets in the horizontal and vertical directions was also simulated. Finally,the simulations of impact of a molten droplet on an inclined plane and a sharp edge were presented. It is concluded that the relative distance of the two droplets strongly influences the dynamics of the two droplets interaction. The various surface conditions have direct effects on the dynamics of splat formation. When a droplet impacts onto an inclined surface and a sharp edge,the splat morphology changes obviously and the phenomenon of break up is observed.展开更多
The cross-sectional analysis on hydroxyapatite （HA） coating and HA+TiO2 composite coating was conducted by using electron probe microanalyser （EPMA）. The results reveal that annealing at 650 ℃ leads to the cracki...The cross-sectional analysis on hydroxyapatite （HA） coating and HA+TiO2 composite coating was conducted by using electron probe microanalyser （EPMA）. The results reveal that annealing at 650 ℃ leads to the cracking within the HA coating or along the coating/substrate interface. The ribbon-like regions in HA coating are verified to contain less PO4-4 groups resulted from the high temperature melting of HA particles in plasma flame. From the viewpoint of microstructural observation, it can be concluded that the addition of TiO2 into HA coating can effectively strengthen and toughen the whole coating system with a shift of the well-bonded interface from the THA （top HA） coating/HTBC （HA+TiO2 bond coat） interface in the as-sprayed THBC （top HA-HTBC） coating to the HTBC/Ti substrate interface in the heat treated THBC coating. The THA coating bonds well to Ti substrate perhaps via its TiO2 hobnobbing with the Ti oxides formed on the Ti substrate.展开更多
基金Project (50675072) supported by the National Natural Science Foundation of Chinaprojects (E0610018, 20062178) supported by the Natural Science Foundation of Fujian Province and Liaoning Province, China, respectively
文摘Plasma spray forming shows overwhelming advantages in rapid fabricating parts and moulds. The coating microstructure is strongly dependent on the splat morphology and inter-splat contact nature. Therefore,it is necessary to investigate the splat formation mechanism in order to analyze the coating properties. A dynamical process of a single fully molten droplet impacting onto a smooth surface was investigated. At the same time,the interaction between the two molten droplets in the horizontal and vertical directions was also simulated. Finally,the simulations of impact of a molten droplet on an inclined plane and a sharp edge were presented. It is concluded that the relative distance of the two droplets strongly influences the dynamics of the two droplets interaction. The various surface conditions have direct effects on the dynamics of splat formation. When a droplet impacts onto an inclined surface and a sharp edge,the splat morphology changes obviously and the phenomenon of break up is observed.
文摘The cross-sectional analysis on hydroxyapatite （HA） coating and HA+TiO2 composite coating was conducted by using electron probe microanalyser （EPMA）. The results reveal that annealing at 650 ℃ leads to the cracking within the HA coating or along the coating/substrate interface. The ribbon-like regions in HA coating are verified to contain less PO4-4 groups resulted from the high temperature melting of HA particles in plasma flame. From the viewpoint of microstructural observation, it can be concluded that the addition of TiO2 into HA coating can effectively strengthen and toughen the whole coating system with a shift of the well-bonded interface from the THA （top HA） coating/HTBC （HA+TiO2 bond coat） interface in the as-sprayed THBC （top HA-HTBC） coating to the HTBC/Ti substrate interface in the heat treated THBC coating. The THA coating bonds well to Ti substrate perhaps via its TiO2 hobnobbing with the Ti oxides formed on the Ti substrate.
