Fabrication of porous Ni–YSZ anodes by PSH-PIM

Abstract

This paper has investigated the fabrication process of porous Ni–YSZ anodes by the powder injection molding method, in which a powder space holder (PSH) is used. Polymethyl methacrylate (PMMA) has been used as a PSH for mixing with NiO–YSZ powders. For this study, five kinds of feedstock containing 0%, 10%, 20%, 30%, and 40% PMMA by volume were prepared. The thermoplastic binder used for the process had a fixed 35 vol.%, and the powder loads formed the remaining 65, 55, 45, 35, and 25 vol.% of the feedstock. After molding and debinding, the parts were sintered at 1,500 °C. The obtained results showed that increasing the PMMA portion of the feedstock and reducing its powder load causes the viscosity of the feedstock to decrease. The amount of shrinkage of the samples containing 0–30% PMMA showed an almost linear increase with the increase of the PMMA content, and for the samples with 40% PMMA, this increase of shrinkage was higher. The amount of porosity in the samples having 0–30% PMMA increased with the rise in the PMMA content, but in the samples containing 40% PMMA, the amount of porosity decreased, such that it was less than that of the samples with 30% PMMA. The electrical conductivity and flexural strength of all the samples were also studied in this work.