Zirconia splat formation and resulting coating properties
- CEA/DAM, Bruyeres le Chatel (France)
- Univ. de Limoges (France)
The aim of this paper is to show the influence of particle parameters at impact and substrate temperature on splat formation. During plasma spraying, the flattening of the particles on the substrate was studied using either a set-up derived from the line-scan test or a system integrating two fast (100 ns) two-color pyrometers. These devices allowed the authors to determine the distributions of diameters and shape factors of the collected lamellae as well as their cooling rates on polished steel substrates at different temperatures, with various oxidation rates. Results on zirconia powders are presented for two particle size distributions: {minus}45 + 22 {micro}m and {minus}90 + 45 {micro}m. Two d.c. plasma torches and a r.f. plasma torch were used in order to get different particle velocities at impact, i.e. in the range 20--200 m/s. During spraying, the substrate temperature was held either at 75 C or 300 C and the substrates were plasma jet preheated during various times ranging from 30 to 900 s in order to modify the oxide layer thickness. Plasma sprayed zirconia coatings -- 300 {micro}m thick -- realized with the three plasma torches were compared with a special emphasis on their adhesion-cohesion. Such results, in good correlation with those obtained for the splats, depend strongly on particle velocity at impact, substrate temperature and oxide layer thickness.
- OSTI ID:
- 377768
- Report Number(s):
- CONF-9509182--; ISBN 0-87170-541-9
- Country of Publication:
- United States
- Language:
- English
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