Thermochemical analysis on the growth of NiAl2O4 rods

Abstract

We have succeeded in growing cubic submicron-sized NiAl2O4 rods on sapphire substrates by means of heating a mixture of NiO and graphite powders. At 1600 degrees C, NiAl2O4 rods terminated by SiOx-containing nanoparticles were grown on the sapphire substrates. In contrast, NiO rods grew randomly at 1500 degrees C. We elucidated the growth steps of cubic NiAl2O4 submicron-sized rods on the basis of a thermochemical approach, revealing the critical role of liquid silica that blocks the continuous loss of Ni to the vapor phase for the successful growth of NiAl2O4 rods.