A statistical approach to the design and fabrication of anode material for solid oxide fuel cells - A case study

This paper investigates a statistical approach to optimizing the process variables for producing pressed and sintered anode material with the desired amount of porosity. The anode material studied is a Ni/YSZ cermet for use in a solid oxide fuel cell (SOFC). A fractional factorial design matrix was generated to study the influence of four process variables at three levels (3 IV4-1 design) on the volume of porosities in the sintered part. The process variables are volume fraction of graphite binder, ratio of volumes of precursor oxides (nickel oxide and yttria-stabilized zirconia), compaction pressure and sintering temperature. Test specimens were made by weighing, pressing and sintering the constituent powders according to the design matrix. The sintered specimen dimensions were measured and the specimens were weighed for density and porosity calculation. Analysis of variance (ANOVA) method was used to study the independent effects and the interactions of the variables on the porosity values. The studies revealed that there was a significant interaction between the graphite vol. % and the sintering temperature on the porosity values apart from their main effects. The results of this statistical study are critical for setting process parameters to obtain optimal anode microstructure. Significance: The statistical approach to process optimization provides materials engineers with an unbiased methodology for screening the significant parameters that affect the fabrication of Solid Oxide Fuel Cells. This was demonstrated in the case of pressed and sintered anode material for solid oxide fuel cells. © INTERNATIONAL JOURNAL OF INDUSTRIAL ENGINEERING.