Sinterability of the oxynitride LaTiO₂N with perovskite-type structure

Based on a thermal stability study, the sinterability of the oxynitride LaTiO₂N was investigated by spark plasma sintering (SPS). The results show that LaTiO₂N is thermodynamically unstable above ca. 400 C in air and ca. 800 C in argon. While it appears impossible to completely avoid decomposition during sintering, LaTiO₂N ceramics with relative density of 74-94% and a residual LaTiO₂N content of 57-90 wt% were prepared. By manipulating kinetics, a relative density of 94% was achieved at 1350 C under an uniaxially applied pressure of 125 MPa. This density is higher than any other counterparts prepared by conventional sintering so far. SPS appears a feasible tool for manipulating the sintering kinetics. It enables the preparation of almost dense LaTiO₂N bulks with adequate purity.