纳米多孔硅粉的化学腐蚀及其理化性质表征

Preparation of Nanoporous Silicon Powder by Chemical Etching and its Physicochemical Properties Characterization

以纯度大于99%,粒径20μm以下的硅粉为原料,以HF、HNO3、蒸馏水及亚硝酸钠为腐蚀介质,采用化学腐蚀法制备纳米多孔硅粉。利用扫描电镜、全自动比表面积仪以及傅里叶变换红外光谱仪对纳米多孔硅粉进行了表征。制备了多孔硅/高氯酸钠复合材料并进行了燃烧实验。结果表明,腐蚀体系中硝酸浓度是影响孔径分布的主要因素。腐蚀时间则是增大纳米多孔硅粉比表面积的关键因素。最佳腐蚀条件为硝酸浓度5.2%,腐蚀时间120 min。制备的纳米多孔硅粉为介孔材料,表面存在大量的硅-氢键,比表面积达58.2264 m2·g-1。制备的多孔硅/高氯酸钠复合材料能剧烈燃烧,伴有爆燃现象,能用作绿色点火药剂或燃烧剂。

Nanoporous silicon powder was prepared by chemical etching method using silicon powder with purity of over 99% and particle size of smaller than 20 μm as raw material and HF, HNO3 , distilled water and sodium nitrite as the etching medium The nanoporous silicon powder were characterized by scanning electron microscope（SEM）, specific surface tester and Fourier transform infrared spectrum （FTIR）. The porous silicon （PSi）/sodium perchlorate composite materials were prepared and their combustion test was performed. Results show that the main factor affecting the pore-size distribution is nitric acid concentration in the etching system. The etching time is the key factor increasing the specific surface area of nanoporous silicon powder. The best etching conditions are nitric acid concentration of 5.2% and etching time of 120 min. The prepared nanoporous silicon powder is nanoporous materials, whose surface is covered by large amounts of Si-H bonds and the surface area is up to 58. 2264 m^2· g^-1. The prepared PSi/sodium perchlorate can combust violently, accompanied with deflagration phenomenon and can be used as green ignition reagent or combustion agent.