Planar solid oxide fuel cell (SOFC) systems offer advantages over tubular designs especially with respect to their ease of fabrication [1]. New ceramic processing technology has enabled thin zirconia electrolyte plates to be fabricated with much lower voltage losses. The development of the SOFC cell has hinged around the cell performance and it has been shown that the Ni-yttria fully stabilized zirconia (FSZ) cermet anodes have much higher overvoltages when compared to the La(Sr)MnO3 cathodes [2]. As such, development of the SOFC cell has concentrated on excellent electrode performance and methods of preparation and adhesion [3]. Most of these methods involve the use of expensive equipment and are very time consuming. However, the planar SOFC systems can be developed using non-vacuum techniques that enable thin, homogeneous electrodes to be adhered to the electrolyte. Techniques for adhesion of the anode onto the electrolyte have included slurry painting and wet powder spraying [4]. The work of Kawada et al. [5, 6] showed that the electrode characteristics were very dependent on the preparation method when using a slurry painting technique, and little control of the thickness of coating was apparent. Ruder et al. [7], however, used a wet spraying technique as a surface application process to produce thin electrode coatings. Wet powder spraying primarily involves spraying a powder-carrier-binder mixture onto a surface by means of an air-brush. The principal steps involved in the wet powder spraying process are mixture preparation, spraying, drying and sintering. The NiO powder was synthesized using a standard solic[ state method [8]. The particle size of the powder was determined using a Malvern particle size analyser and a milling schedule was implemented to ensure particle sizes of less than 1/tin. The correct volume proportions of the NiO and the fully stabilized zirconia powder (8 mol % Y203 stabilized zirconia, provided by Tosoh, Japan) were put into a 30 ml vial with half the volume of the vial containing 95% ethanol and the FSZ grinding media. The sample was then milled for 24 h, separated from the grinding media, poured into petri dishes and heated at 90 °C until evaporation of the ethanol had occurred. The powders were then removed from the dishes and placed into platinum crucibles and fired at 1200 °C, using a slow heating and cooling rate (+ 5°Cmin-~), for 2h. Each sample was then re-ground to remove any agglomerates present. The cermet was then added to methyl-ethyl ketone (as the carrier phase), sodium-free cooking spray (as the dispersant) and poly vinyl butyral (PVB) (as the binder) and mixed for 2 h, in a sealed container, to form a semi-stable, homogeneous, dispersed slurry which had a viscosity (measured using a Brookfield viscometer, with a micro-sample adaptor) or 60 cP. Table I shows the typical composition of the "paint" for application as an anode onto an 8 mol % Y203 FSZ electrolyte, 5 cm x 5 cm x 150/~m thick, for fabrication into a single or multi-cellular SOFC system. The slurry was placed into an air-spray gun (Badger air-brush system) with a continual supply of high pressure air to aid in the mixing of the cermet while spraying. The quality of the spray stream, which consequently controlled the coating thickness and uniformity, was controlled by the spray velocity, the distance and angle between the air-brush nozzle and the substrate, and the number of passes. The FSZ electrolyte was washed in ethanol and calcined at 500 °C, prior to the application of the anode coat. All electrolytes were stored in a desiccator just before they were to be fabricated into single cells. The air-brush was then used to spray an even coat of the cermet onto the electrolyte and the system was sintered at 1300 °C for 2 h (using a slow heating and cooling rate). The spraying parameters were varied to achieve a porosity of 30-50% estimated by the linear intercept method [7]. During air-brushing, the mixture should arrive at the substrate in a semi-dry condition due to the evaporation of the carrier phase. This semi-dry condition is preferable, because uncontrolled dripping and wetting can be avoided. The method was used to spray even thin layers of the cermet onto the substrate and consequently build up a layer about 50 #m in thickness. A small spray bay has been set up to provide an area for clean contamination-free spraying, using a fixed, or variable, spraying distance with excellent reproducibility. After the sintering stage had been achieved, the sample was then reduced in a N2/H2 (saturated with water) atmosphere tube furnace at