Title :
Behaviour of dispersed ceramic particles in DC arc plasma jet during the spray deposition of coatings
Author :
Valincius, Vitas ; Grigaitiene, Viktorija ; Valatkevicius, Pranas
Author_Institution :
Lithuanian Energy Inst., Kaunas, Lithuania
Abstract :
The present study offers the results indicating the regularity of the motion and energy distribution in two phase plasma jet. The research was carried out on the novel developed plasma spray deposition system with linear direct current (DC) plasma generator (PG) operating at atmospheric pressure. The shadowgraphy and CCD technique were successfully applied to determine the behavior of Al(OH)3 dispersed particles in plasma jet. The structure of coatings was studied using SEM and XRD. It was found that during the plasma spray pyrolysis process dispersed particles are partly melted and deformed due to intensive heat transfer. Jet kinetic energy, turbulence and temperature fluctuations cause the formation of granules from Al(OH)3 powder and increase the mechanical stresses on its surface. The results also showed that the interaction of dispersed particles 50 - 150 μm of diameter with plasma jet in the distance of 120 mm from the exhaust nozzle of plasma generator, take up to 0.3 miliseconds in time. The spherical particles moving towards the substratum get partly melted. The most rapid melting observed in the distance of x/d=(3-8).
Keywords :
X-ray diffraction; aluminium compounds; ceramics; deformation; fluctuations; heat transfer; internal stresses; melting; nozzles; plasma arc sprayed coatings; plasma arc spraying; plasma jets; plasma production; pyrolysis; scanning electron microscopy; turbulence; Al(OH)3; Al(OH)3 dispersed particles; CCD technique; DC arc plasma jet; SEM; XRD; atmospheric pressure; deformation; dispersed ceramic particles; distance 120 mm; energy distribution; exhaust nozzle; granules; intensive heat transfer; jet kinetic energy; linear direct current plasma generator; mechanical stresses; melting; motion regularity; plasma spray deposition system; plasma spray pyrolysis; powder; shadowgraphy; size 50 mum to 150 mum; spherical particles; spray deposition coatings; temperature fluctuations; turbulence; two-phase plasma jet; Anodes; Plasma temperature; Powders; Spraying;
Conference_Titel :
Plasma Sciences (ICOPS) held with 2014 IEEE International Conference on High-Power Particle Beams (BEAMS), 2014 IEEE 41st International Conference on
Conference_Location :
Washington, DC
Print_ISBN :
978-1-4799-2711-1
DOI :
10.1109/PLASMA.2014.7012743
