Low-temperature method for manufacturing nano-MgO crystal whisker

Abstract

The invention relates to a method for preparing nanometer MgO whiskers at the low temperature and the method is that magnesium powders and amorphous boron powders are mixed according to atomic ratio of MG:B being equal to 1 to 1.5:2 and the mixture is grinded for 30 to 120 minutes for thorough mixing, and after the mixed powders are made into a lump sinter under the pressure of 5 to 10 kg / cm<3> bya press machine, the lump sinter is put into a crucible which is put into a heating zone of an evacuated tubular furnace. The evacuated tubular furnace is sealed, vacuumized to 1 to 10 Pa and filledwith argon the oxygen content of which is 2 percent to 5 percent and the flow rate of the mixed gas is 5 to 20 lit. per minute to heat the sample up to 650 to 750 DEG C at the heating rate of 5 to 20K per minute, and the sample is decreased to the room temperature at the same heating rate after the temperature is kept for 0 to 120 minutes. The surface of the sample forms nanometer MgO whiskers with various appearances and sizes. When reaching 650 DEG C, magnesium evaporates and reacts with the little filled oxygen to produce MgO vapour, and under the lower over-saturation state, MgO whiskersare deposited on a substrate. The method for preparing MgO whiskers needs temperature much lower than the previous and greatly increases the practicality of preparing MgO whiskers.

Description

technical field [0001] The invention belongs to the technical field of composite materials, in particular to a low-temperature preparation method of nanometer MgO whiskers. Background technique [0002] As a very important material, magnesium oxide (MgO) is widely used as catalyst, toxic substance adsorbent and additive for refractory materials, coatings and superconducting materials. In addition, as a typical wide-band (gap) insulator, the electronic and optical properties of MgO bulk materials have received extensive attention and have been continuously studied in depth. [0003] Recently, MgO one-dimensional nanostructured materials have attracted much attention due to their unique properties and applications in optics, magnetism, superconductivity and ferroelectric phenomena. As a kind of one-dimensional nanostructure, MgO whisker not only has the above characteristics, but also has the advantages of high melting point (2850°C), high strength and high elastic modulus. T...

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Problems solved by technology

[0006] But the problem that the above-mentioned technology exists is: the formation of Mg vapor needs to pass MgB 2 The thermal decomposition is achieved, while MgB 2 The decomposition temperature of MgO is higher than 750°C, and it needs a long time of heat preservation treatment to react with oxygen to form sufficient MgO saturated vapor pressure to meet the growth of MgO whiskers.

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