2004 Volume 112 Issue 1302 Pages 82-87
Electrochemical NOx reduction system composed of three-layered laminate, 8 mol%Y2O3–ZrO2 (YSZ) // 70 vol%YSZ/BaMnAl11O19 (BMA) // 30 vol%YSZ/BMA, could be successfully synthesized at 1550°C by taking into account the shrinkage mismatch between YSZ and YSZ/BMA layers. Two types of alumina, α- and γ-phase, were used as an alumina source for the in-situ processing of the laminate. The total shrinkage of the precursor powder for the composite using γ-alumina was closer to that of YSZ than that using α-alumina. The shrinkage rate of the precursor powder was adjusted to that of YSZ at the heating rate of 2°C/min. The shrinkage curve of YSZ/BMA composite consisted of the first shrinkage region, a plateau region and the second shrinkage region. The plateau region, in which the formation of BMA crystallites inhibited the growth and sintering of YSZ, decreased with increasing YSZ/BMA ratio. The control of heating rate and the use of the intermediate layer with compositional gradient lead to the development of the three-layered laminate tightly bonded with each other without any separation, which can be applied for the electrochemical NOx reduction system.
