Growth of High Magnetic α-Fe₂O₃ and Fe₃O₄ Nanowires via an Oxide Assisted Vapor-Solid Process

We describes a controllable synthesis procedure for growing α-Fe₂O₃ and Fe₃O₄ nanowires. High magnetic hematite α-Fe₂O₃ nanowires are successfully grown on Fe_0.5Ni_0.5 alloy sub-strates via an oxide assisted vapor-solid process. Experimental results also indicate that previous immersion of the substrates in a solution of oxalic acid causes the grown nanowires to convert gradually into magnetite (Fe₃O₄) nanowires. Additionally, the saturated state of Fe₃O₄ nanowires is achieved as the oxalic acid concentration reaches 0.75 mol/L. The aver-age diameter and length of nanowires expands with an increasing operation temperature and the growth density of nanowires accumulates with an increasing gas flux in the vapor-solid process. The growth mechanism of α-Fe₂O₃ and Fe₃O₄ nanowires is also discussed. The results demonstrate that the entire synthesis of nanowires can be completed within 2 h.