| One-dimensional material is a new type of functional materials in the new technology of this century, which is playing an important roal in the material field. Magnesium salt whiskers have high temperature resistance, corrosion resistance, electrical insulation, high strength, high hardness and other characteristics, as a reinforcer has excellent physical and chemical properties and mechanical performance in plastics, metals, ceramics and other materials, which has broad prospects in the future. Therefore, to study the preparation of whiskers is worthy.At present magnesium salt whiskers mainly were prepared by the methods with high temperature, high pressure and high energy consumption, compared with traditional methods this paper adopts the electrochemical method which only requires moderate room temperature and atmospheric pressure conditions. This paper has prepared magnesium borate whisker and magnesium silicate whisker successfully. The main research contents were showed that:(1) Direct oxidation method was used to prepare magnesium borate whisker. The composition and morphology of the magnesium borate whiskers were determined by X-ray diffraction (XRD), scanning electron microscope (SEM), energy spectrum analysis (EDS), infrared spectrum (IR) and thermogravimetric analysis (TG-DTA) measurements. Besides cyclic voltammetry (CV) curve was characterized by three electrodes system to study the electrochemical process and then investigated the affection of temperature, poison agent and current density, discussing the poison mechanism; (2) Direct oxidation method was used to prepare magnesium silicate whisker. The composition and morphology were characterized by SEM, XRD, EDS, IR and TG-DTA means; (3) The microstructures of two kinds of whiskers were calculated by first principle based on the density functional theory. Results showed that:1. We know that the magnesium borate whiskers (Mg2B2O5) are 6～8μm long, each with a diameter of 500nm by SEM, XRD, EDS and IR analysis. It does not contain crystal water. The ratio of the length to the diameter ranges from 12:1 to 16:1. The average current efficiency is 35%; meanwhile the cyclic voltammetry (CV) curve shows that oxidation reaction in the anode happens at about 2.0V and there is no reduction reaction in the cathode; the best conditions are:0.20mol/L poison agent,0.06A/cm2 current density,0.20mol/L sodium chloride, temperature about 20℃,1:3 of the ratio of ethanol and water, 0.44mol/L boric acid.2. The SEM images show that magnesium silicate whiskers are 5～6μm long, each with a diameter of 500nm. The ratio of the length to the diameter ranges from 10:1 to 12:1. It is consistent with the definition of whiskers. The orthogonal characteristic peak is found by XRD spectrum analysis. The crystal structure (Mg2Si04) is analysis by EDS and IR spectrum, and there is another small amount of magnesium oxide. Diffraction peaks are strong which suggests good crystallization; products do not contain crystal water. In order to synthesis whiskers, the current density is needed for 0.6A/cm2.3. Bulk Mg2B2O5 and Mg2Si04 crystal are closed to insulators because the band gap of Mg2B2O5 crystal cell and Mg2Si04 cell are 4.9 eV and 5.0 eV, respectively. The valence band of Mg2B2O5 crystal cell is constituted mainly by O 2p, Mg 3s and B 2s,2p state. Besides the conduction band is made up predominantly of the B 2p component. The valence band of Mg2Si04 original cell is constituted mainly by O 2p, Si 3s,3p and Mg 3s state. The conduction band is made up of Si 3p and a small amount of Mg 3s state. The cohesive energies are also calculated on the Mg2B2O5 crystal cell and Mg2Si04 crystal cell. They are -1444.1990eV and -1646.0148eV respectively. The Mg2Si04 original cell is more stable.In a word, the magnesium borate and magnesium silicate whiskers were prepared by direct oxidation of electrochemical method. It has not been reported in domestic (applied for two invention patents). The study will provide a new solution for the preparation of other whiskers.
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