Abstract:The aim of present work was to produce pure nickel aluminate (NiAl₂O₄) nanoceramic compound by high energy milling of nickel carbonate (NiCO₃) and aluminum (Al) powders followed by annealing. Phase composition, thermal behavior, morphology and microstructure of powder samples were characterized by means of X-ray diffraction, differential scanning calorimeter, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The results showed that formation of NiAl₂O₄ spinel compound from NiCO₃ and Al powders took place in three steps: oxidation of Al to Al₂O₃, decomposition of NiCO₃ to NiO and CO₂, and finally the solid state reaction between Al₂O₃ and NiO. It was also demonstrated that single phase NiAl₂O₄ spinel compound can be produced by 5 h of mechanical milling with subsequent annealing of NiCO₃/Al mixture at 900 °C for 2 h, which is ~500 °C lower than the temperatures used in the traditional solid state methods. The particle diameter of the produced NiAl₂O₄ spinel compound was found to be less than 100 nm as measured by transmission electron microscopy.

Key words: nickel aluminate; nanoceramic; ball-milling; annealing