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Wednesday, May 17, 2006 - 1:50 PM
APP8.1

Hybrid Plasma Spray – PVD Coatings in Triple Torch Plasma Reactor

J. Heberlein, University of Minnesota, Minneapolis, MN; D. Kolman, Technical University of Prague, Prague, Czech Republic; H. Chen, Boston Scientific, Maple Grove, MN

The requirements of ceramic coatings can vary significantly for different applications. Examples are yttria stabilized zirconia coatings in fuel cells which should be very dense when they serve as electrolyte layer, but porous when deposited together with nickel as a cermet anode layer. In the triple torch plasma reactor (TTPR), three plasma torches are arranged such that their jets join to form a larger plasma region, and the deposition precursors, e.g. particles, are injected through a water-cooled probe into this region. Variation of the amount of carrier gas offers some control over particle heating. In this study, we report on measurements characterizing the temperature and velocity fields in the reactor, and on the use of the results to calculate temperature histories of injected YSZ particles of different sizes. The results allowed us to select the conditions for deposition of electrolyte coatings that display characteristics of plasma sprayed coatings as well as vapor phase deposited coatings. The coatings deposited at very high rates, having a porosity of about 0.5%, have been tested as electrolyte layers in solid oxide fuel cells.

Summary: We report results of controlling YSZ coating properties deposited using the triple torch plasma reactor (TTPR). Measurements were made to characterize the temperature and velocity fields in the reactor, and temperature histories of injected YSZ particles of different sizes were calculated. The deposited electrolyte coatings display characteristics of plasma sprayed coatings as well as vapor phase deposited coatings, having a porosity of about 0.5%.