Preparation Of Magnesium Borate One-dimensional Nanostructures

Magnesium borate is a kind of excellent mechanical properties materials, such as light weight, high toughness, heat resistance, wear resistance, corrosion resistance and other characteristics of strengthening and toughening and so on. In recent years, nano-materials research shows that one-dimensional nanomaterials such as nanowires, nanotubes, nano-belts, and nano-rods ,of which mechanical properties are usually better than its micron whisker. Recently, there have been many reported in the literature on preparation of One-dimensional nanomaterials of magnesium borate , including chemical vapor deposition (CVD), high temperature sintering, sol-gel method, micro-emulsion method and other methods.Electrospinning is a new method of preparation of nanofibers, the thesis introduce from the principle of electrospinning ,formation mechanism of nanofibers . the influential factors of fibers forming. Mechanical milling method is a simple process, low cost, high efficiency, and suitable for industrial production of nano-materials synthesis.For these reasons, the electrospinning technique and mechanical milling synthesis of magnesium borate nanofibers, nanorods. The main experimental procedure is listed as follows1. electrospinningThe experiment applicate H3BO3 and Mg (CH3COO)2 as a reactant in accordance with the molar ratio of 1:1 ,PVP agent / H3BO3 and Mg (CH3COO)2 made from the precursor solution for electrospinning. In the elespinning process, distance of the spinneret and the collection plate is 12cm, electrospinning voltage is12kv. collection plate get composite fiber of PVP / magnesium acetate and boric acid. fiber membrane are sample at 550℃, 650℃, 750℃, 850℃,respectively. XRD Spectrum show that there was a Mg3B2O6 characteristic peak on sample at 650℃, this phenomenon may be show formation of mall number of Mg3B2O6 grain over time and temperature increaseing. Therefore, the sample spectrum at 750℃find Mg3B2O6 characteristic peak significantly increaseing. when the temperature rises to 850℃, intensity of Mg3B2O6 characteristic peak increased significantly,samples sprectrum appear more clear and complete simple orthogonal structure of Mg3B2O6 peaks, At the same time ,according to scherrer formula, the grain size increase with temperature growth.SEM images analysis that PVP / borate composite fiber show thickness uniformity, little beads, droplets, average diameter of 300-400nm.With temperature growth , the fiber diameter slightly slender, When it reach the crystallization temperature, fiber diameter slightly thicker, according to SEM image at different temperature ,fiber show roughness and perforated surface may due to PVP, acetateand boric acid decomposition, volatilization of gas. Mg3B2O6 crystal is beginning to form and emit a lot of heat,so that the morphology of the fibers the happen larger change. Comparison to other methods,our synthesized nano-fiber is more uniform thickness,length is also longer.2. mechano-chemicalA new route for the synthesis of Mg₂B₂O₅ nanorods is reported, using NaBH4 and MgCl26H2 O as B and Mg source via mechano-chemical and sintering process. The experimental results show that the solid-state exchange reaction has taken place and the disordered Mg-B-H may be formed during the mechano-chemical process. By sintering at 800 for 2h, the monoclinic Mg₂B₂O₅ nanorods with width of 200nm and length of about 4⁵m are formed, which are single crystalline and twinned structure. The by-product NaCl is necessary for the formation of the single phase Mg₂B₂O₅Nanorods. This novel route is not only a simple, cost-effective and environmental technique for the synthesis of magnesium borate but also a technique which allows other metal borates to be used synthesizing nanorods for fundamental research and potential applications.