Abstract:
Statistical design of experiments was used to model electrophoretic deposition of yittria-stabilized zirconia (YSZ) particles on porous, non-conducting NiO-YSZ substrates. A 2(3)-full-factorial matrix with three repetitions of the centerpoint was augmented with six axial runs and two additional centerpoints to form an inscribed central composite design. Fixed ranges of substrate firing temperature (1100 degrees-1300 degrees C), deposition voltage (50-300 V), and deposition time (1-5 min) were used as the independent design variables to model responses of YSZ deposition thickness, area-specific interfacial resistance (ASR), and power density. Regression equations were determined, which were used to optimize deposition parameters based on the desired responses of low interfacial polarization resistance and high-power density. Low substrate firing temperature (1100 degrees C) combined with a low voltage (50 V) and minimal deposition time (1 min) resulted in a 6 mu m-thick YSZ film, a power density of 628 mW/cm(2), and an ASR of 0.21 Omega.cm(2). Increasing the substrate firing temperature, voltage, and time to 1174 degrees C, 215 V, and 3 minutes, respectively, reduced the ASR to 0.19 Omega.cm(2), increased YSZ film thickness to 25 mu m, but had only a negligible effect on power density (600 mW/cm(2)).