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Preparation of aluminum diboride

wallpapers News 2021-12-29
In recent years, aluminum diboride has gradually attracted people's attention because of its unique properties. Aluminum diboride can not only be used as a particle strengthening agent to improve the wear resistance of the alloy but also can remove the transition element impurities Cr, Ti, V, Zr in the liquid aluminum, thereby improving the conductivity of aluminum. In addition, due to its higher theoretical combustion heat, AlB2 can also be used as a fuel additive. In addition, like other borides (ZrB2, MgB2, CaB6, B4C), AlB2 also has a good effect on improving the oxidation resistance of carbon-containing refractories. Su-nayama's research results show that adding AlB2 to MgO-C refractories helps reduce carbon oxidation by forming a liquid phase.
At present, the main methods for preparing aluminum diboride are the smelting method and solid phase sintering method, and both of these methods have the disadvantages of a long time and high energy consumption. Self-propagating high-temperature synthesis (SHS) is a new method for preparing materials first proposed by Russian scientists Merzhanov and Borovinskaya in 1967. Compared with the above two methods, this method has many advantages, such as high purity of the prepared product, simple process, short reaction time, and low energy consumption. Al-B is a weakly exothermic combustion system, so preheating is required to achieve self-sustained combustion. The use of the chemical oven preheating method to achieve AlB2 chemical oven self-propagating high-temperature synthesis (Chemical oven self-propagating high-temperature synthesis, abbreviated as C.O.SHS) is rarely reported. The so-called chemical furnace is a covering layer of a mixture material with strong exothermic reaction potential placed around the reaction body with a very low inherent adiabatic temperature. The strong heat provided by the combustion reaction of the covering layer makes the weakly exothermic reaction system placed in it. A combustion synthesis reaction occurs.
In addition, Al and B can be used as raw materials, C and Ti as chemical furnaces, and AlB2 can be prepared by chemical furnace self-propagating high-temperature synthesis technology (COSHS), and the phase composition of the product can be analyzed by X-ray diffractometer (XRD), and field emission scanning can be used Electron microscope (FESEM) study the microscopic morphology of the product. According to the basic principles of thermodynamics, thermodynamics software (Factsage 6.4) was used to study the effect of initial reaction temperature on adiabatic temperature.

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