MgO晶须的原位固相合成及其生长机理研究

In-situ Solid-state Formation and Growth Mechanism of MgO Whiskers

以AZ91D合金粉末和H3BO3为原料,采用X射线衍射（XRD）、扫描电镜（SEM）及X射线能谱分析（EDS）研究了原料配比和烧结温度对原位固相合成MgO晶须的形貌及其物相变化的影响.结果表明,当Mg/B物质的量比为15∶4时,在惰性气氛条件下采用烧结温度800℃和保温时间2h的工艺可以制备出长度和直径分别为1～3μm和0.1～0.3 μm的MgO晶须;探讨了MgO晶须的生长机理,认为MgO晶须的生长符合溶液（Solution）-液（Liquid）-固（Solid） （SLS）机制.

The effect of the molar ratio Mg/B in the solid state mixture of magnesium alloy powder AZ91D and H3 BO3, and sintering temperatures on the phase transformation and morphology of MgO whiskers was investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM） equipped with a micro-analysis system of energy dispersive spectroscopy （EDS）, respectively. The experimental results showed that the MgO whiskers with diameters of 0. 1--0. 3 μm and lengths of 1--3 μm could be formed during in-situ sintering of a mixture with mole ratio 15 ： 4 of magnesium alloy powder AZ91D to H3BO3 in Ar atmosphere at 800 ℃ for 2 h. The growth process of MgO whiskers is dominated by a solution-liquid-solid （SLS） mechanism.