硼酸镁晶须的可控合成及表征

以六水合氯化镁和硼酸为原料，在水热条件下合成了碱式硼酸镁［MgBO2（OH）］晶须，将其焙烧得到硼酸镁（Mg2B2O5）晶须。采用X射线衍射（XRD）、扫描电镜（SEM）和热重-差热分析（TG-DTA）手段，对前驱体和焙烧产物的物相和形貌进行表征。主要考察了反应物浓度对前驱体物相和形貌的影响，并分析前驱体的形成过程。结果表明，前驱体的制备过程与反应物浓度直接相关，在Mg2+浓度为2.0 mol/L，硼酸浓度为0.75 mol/L的条件下，可合成形貌良好的碱式硼酸镁晶须，将其在较低焙烧温度650 ℃下焙烧3 h，可得到组分单一、直径为40~70 nm、长度为500~1 500 nm、长径比为10~20的硼酸镁晶须。

Controllable synthesis and characterization of magnesium borate whisker

The precursors，basic magnesium borate whiskers［MgBO2（OH）］were hydrothermally synthesized with magnesium chloride hexahydrate（MgCl2·6H2O） and boric acid（H3BO3） as the raw materials.Magnesium borate（Mg2B2O5） whiskers were obtained by calcination of the precursors.The compositions and morphologies of MgBO2（OH） and Mg2B2O5 were characterized by XRD，SEM，and TG-DTA. The influence of the reactant concentration on the composition and morphology of MgBO2（OH） was mainly investigated.The forming process of the precursors was also analyzed.Results showed that，the precursors′ prepa-ration was directly related to the concentration of the raw materials.When the concentration of Mg2+ was 2.0 mol/L，and the concentration of H3BO3 was 0.75 mol/L，MgBO2（OH） whiskers with good morphology could be synthesized.The subsequentthermal conversion of the MgBO2（OH） whiskers at a relatively low temperature of 650 ℃ for 3 h led to pure phase of  Mg2B2O5 whiskers，with the diameter of 40~70 nm，the length of 500~1 500 nm，and the aspect ratio of 10~20.