关键词: 菱面片层MgO, 热分解, 微观形貌, 晶体生长, 影响因素

Abstract: Rhombic magnesia flakes with multi interspaces were prepared by calcining magnesium hydrate. The precursor of MgO could be obtained via acid immersing twice and ammonia depositing from dolomites. The structure, morphology, and composition of MgO and its precursor were characterized by means of XRD, FT-IR, SEM, and TEM methods. The results indicated that EDTA and PEG molecules were possessed of the effect directing the radial epitaxial growth of Mg(OH)2 flakes. The rhombic magnesia nanoflakes with 10-20 nm in thickness and up to 1 μm2 in area of main surface are single crystal with cubic crystal structure. It grows with a preferred orientation along the [100] direction and inherits the features of radial epitaxial growth of Mg(OH)2. The orientated growth mechanism of the MgO nanoflakes was studied based on corresponding thermodynamics and dynamics theories.

Key words: Rhombic magnesia flakes, Thermal decomposition, Microscopic morphology, Crystal growth, Effect factors