以活性氧化镁和氯化镁为原料合成氧化镁晶须

The synthesis of magnesium oxide whisker from active magnesium oxide and magnesium chloride

探讨了一种合成氧化镁晶须的新的工艺方法。首先以活性氧化镁和氯化镁为原料合成了前驱体碱式氯化镁晶须，接着将碱式氯化镁焙烧成氧化镁晶须。分别用X射线衍射仪（XRD）、扫描电镜（SEM）、热重分析仪（TGA）和化学分析，分析了中间体碱式氯化镁和产品氧化镁晶须的成分、形貌和热化学行为。探讨了各个工艺条件对产物的影响，探索出最佳的工艺条件：活性氧化镁与氯化镁的物质的量比在0．08左右，氯化镁溶液的浓度为3mol／L，反应温度40～50℃，陈化时间在48-72h，陈化温度50℃。在此条件下制得了形貌良好的前驱物碱式氯化镁晶须。将碱式氯化镁晶须焙烧，控制升温速率在2—5℃／min，采取分段升温方式升温至600℃，即可制得氧化镁晶须。制得的晶须长度在100μm左右，直径约0．5μm。

This paper presents a new route to prepare magnesium oxide whiskers. The preparation process consists of the synthesis of a precursor called basic magnesium chloride whiskers, followed by the heat treatment of the synthesized whiskers. The precursor whiskers were prepared by active magnesium oxide and magnesium chloride as raw materials. These two whiskers were characterized by X - ray diffraction （ XRD ）, scanning electronic microscopy （ SEM ）, tbermo - gravimetric analysis （TGA） and chemical analysis on their composition, morphology and thermal behavior. The influence of each condition to the products was discussed and the best conditions were found as follows ： the mole ratio of active magnesia and the magnesium chloride is about 0.08, the magnesium chloride solution concentration is 3 mol/L, the reaction temperature 40 - 50 ℃ ,the ripening time is between 48 - 72 h, the ripening temperature is 50 ℃, under these conditions, the basic magnesium chloride whiskers with good morphology were prepared. Then the basic magnesium chloride whiskers were caleinated under the speed of elevated temperature in 2 - 5 ℃/min until the temperature to 600 ℃ by separate steps, then the magnesium oxide whiskers were prepared. The length and diameter of whisker are about 100μm and 0.5 μm respectively.