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| Abstract No.: |
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Scheduled at:
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Thursday, May 12, 2016, Room 3G 3:00 PM
Plasma Spraying
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| Title: |
Evaporation enhancement at very low pressure by modifying the nozzle for conventional 80 kW plasma spray system
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| Authors: |
Chang-Jiu Li / Xi'an Jiaotong University, P.R. China
Qing-Yu Chen / State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering,, China
Cheng-Xin Li*/ State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering,, China
Guan-Jun Yang/ State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering,, China
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| Abstract: |
The nozzle shape has a great effect on the characterization of plasma jet such as velocity and temperature distribution which is directly associated to the particle velocity and temperature. The particle temperature is the main influence factor to particle evaporation. In this paper, a modified nozzle with a large orifice was used to reduce the velocity of plasma jet in order to prolong the dwelling time of spray particle in plasma jet. Optical emission spectrometer (OES) was employed to characterize the temperature, electron number density of plasma jet. The deposition characteristics of YSZ coatings by PS-PVD using 80 kW plasma spray system in vacuum condition at the condition of droplet filtering were examined. Field emission-scanning electron microscope (FE-SEM) was used to characterize the microstructure of the YSZ coatings. The results show that the temperature and electron number density of plasma jet with the modified nozzle of large orifice are larger than that with the normal nozzle. The surface morphology of coating deposited through droplet filtering exhibits a typical island-structure which is composed of nano-particles with angle shape. The cross section morphology of above fracture coating shows a columnar-structure. Through droplet filtering, the thickness of columnar-structure coating deposited with modified nozzle is much larger than that with normal nozzle. The higher temperature and electron number density enhance the intensity of YSZ particle evaporation, resulting in a higher deposition rate with modified nozzle than that with normal nozzle.
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