Flaky and Porous Rod-like MgO Powders Prepared by Molten Salt Synthesis

Flaky and porous rod-like MgO powders were prepared by molten salt synthesis with MgCl2, CaCO3, NaNO3 and KNO3 as raw materials. TG-DSC, XRD and SEM were used to investigate the reacion process and characterize the resulting products. The results indicated that Ca2+ was displaced by Mg2+ and dolomites were formed and finally converted into magnesium carbonates during the molten salt synthesis. Fibrous Mg(OH)(2) formed in PEG solution and flaky Mg(OH)(2) formed in EDTA-PEG solution illustrated that EDTA and PEG molecules could define the growth direction of Mg(OH)(2). The porous rod-like MgO powders with 20-80 nm in diameter and 40-100 in length-to-width ratio were obtained by the decomposition of fibrous Mg(OH)(2) at 600 degrees C, while the flaky MgO powders were prepared by the decomposition of flaky Mg(OH)(2) at 600 degrees C. Flaky MgO powders were platelike, with 30-50 nm in thickness, 200-500 nm in diameter, and up to 1.0 mu m(2) in a single slice surface area.