Spark plasma sintering (SPS) of plasma sprayed YSZ electrolyte for solid oxide fuel cell (SOFC) application

摘要

Spark plasma sintering is found to be an effective method for densifying the plasma sprayed yttria stabilized zirconia discs for solid oxide fuel cell (SOFC) applications. After SPS, the lamellar microstructure of plasma sprayed YSZ changed into predominantly granular-type structure. The micro-hardness and Young's modulus increased proportionately with the SPS post-treatment temperatures. Compared with the increasing in soaking time in a single cycle SPS process, increasing the multiple SPS cycles with a relatively short soak time was found to significantly den-sify the sample without any severe grain growth. And there are an optimum number of SPS cycles for such an effect. So with proper multiple SPS cycles and with a relatively short soaking time it was found that a more positive effect on the improvement of mechanical properties of the plasma sprayed YSZ discs was observed. The thermal conductivity of the plasma sprayed YSZ is greatly improved (up to 2 times) by the SPS post-heat treatment. This has a positive influence on the eventual performance of the YSZ as an electrolyte in a SOFC assembly. The viability of SPS as an effective post-spray treatment has been demonstrated.