Effects of Processing Parameters on the Synthesis of (K(0.5)Na(0.5))NbO(3) Nanopowders by Reactive High-Energy Ball Milling Method

The effects of ball milling parameters, namely, the ball-to-powder mass ratio and milling speed, on the synthesis of (K(0.5)Na(0.5))NbO(3) nanopowders by high-energy ball milling method from a stoichiometric mixture containing Na(2)CO(3), K(2)CO(3), and Nb(2)O(5) were investigated in this paper. The results indicated that the single crystalline phase of (K(0.5)Na(0.5))NbO(3) was received in as-milled samples synthesized using optimized ball-to-powder mass ratio of 35 : 1 and at a milling speed of 600 rpm for 5 h. In the optimized as-milled samples, no remaining alkali carbonates that can provide the volatilizable potassium-containing species were found and (K(0.5)Na(0.5))NbO(3) nanopowders were readily obtained via the formation of an intermediate carbonato complex. This complex was mostly transformed into (K(0.5)Na(0.5))NbO(3) at temperature as low as 350°C and its existence was no longer detected at spectroscopic level when calcination temperature crossed over 700°C.