Synthesis and properties of novel blue zirconia ceramic based on Co/Ni-doped BaAl12O19 blue chromophore

Solid solutions based on BaAl 12- x M x O 19 (M = Co 2+ , Ni 2+ ) showing intense blue shades were successfully synthesized by conventional solid state reaction. Then, novel zirconia ceramic materials with intense blue hues were then prepared upon addition of 5 wt% of the synthesized chromophore to a ZrO 2 white matrix containing 5 wt% Y 2 O 3 and sintered at 1400 °C for 6 h. The colors of the BaAl 12- x Co x O 19 or BaAl 12- x Ni x O 19 are due to the d-d transitions of Co 2+ or Ni 2+ in tetrahedral coordination, respectively. The colored zirconia ceramics were all indexed with tetragonal phase. The coexistence of the chromophore and ZrO 2 were observed by scanning electron microscopy and energy dispersive spectrometer. The hardness of the as-synthesized blue zirconia ceramic was slightly higher as compared to the pure undoped sample.