화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.37, No.23, 18365-18371, 2012
Constrained sintering of Y2O3-stabilized ZrO2 electrolyte on anode substrate
Understanding the sintering processes extensively is critical in fabricating a flat cell for solid oxide fuel cell stacks, but few have reported the sintering process and stress development during the constrained sintering of the electrolyte layer on anode substrate. In this study, we show that the green tape of half cell fabricated by co-tape casting cracks into several pieces when it is heated directly to 1400 degrees C of profile I, while it remains flat and complete when the green tape is sintered with additional pre-sintered profile at 1300 degrees C of profile II. The strain rate characteristics indicate that the difference of 2.43 x 10(-6) s(-1) between the electrolyte and the anode layer leads to the stress development in the directly sintered cell, while it reduces to 6.7 x 10(-8) s(-1) for the pre-sintered cell, which is only 3% of that without pre-sintering. The stress based on continuum model calculated results in the sintered cell demonstrates that the stress increases from 0 at about 1000 degrees C to 2.60 MPa at 1300 degrees C, and increased from 2.60 MPa to 6.54 MPa in temperature range of 1300-1400 degrees C. But it was lower than half of the stress for the pre-sintered cell according to profile II. The SEM images, together with a circuit voltage of 2.22 V for two cell stack, indicate that the electrolyte of the unit cell is dense. The power is 41.7 W, with a power density of 0.26 W cm(-2) at 1.4 V and 750 degrees C for a two tells stacks sintered according to profile II. The ASR of the two cells stack is 2.50 Omega cm(2). Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.