Structural studies of porous Ni/YSZ cermets fabricated by the solid-state reaction method

Carbon black-added NiO/YSZ composites exhibited a highly porous structure due to the enhanced evolution of CO and CO2 gases associated with exothermic reactions during sintering. The addition of carbon black resulted in a decrease in the density and grain size of NiO/YSZ composites. The porosity of NiO/YSZ composites increased with decreasing the sintering temperature and increasing the NiO content. Additionally, highly porous Ni/YSZ cermets were fabricated by reducing the NiO/YSZ composites in (Ar+6% H2), which was attributed to the change of NiO to Ni and then the extraction of oxygen. The carbon black used as a pore-former was highly effective for preparing porous Ni/YSZ cermets.