Cation inter-diffusion and formation of intermediate phases in CoO and La2NiO4+δ diffusion couples

Abstract

Cation interdiffusion between La2NiO4+δ (LN) and CoO diffusion couples was investigated by thermal annealing in ambient air at 1200 °C for 48 and 168 h, and analysis of the cross sections by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Co diffusion into the LN layer was significant, while Ni diffusion into the CoO layer was minor. Formation of LaCoO3, LaCo0.5Ni0.5O3, and La3(Ni0.8Co0.2)2O7 were observed in the LN layer at increasing distance from the boundary.