热处理对爆炸法制备的碳包裹碳化铁纳米颗粒的影响

EFFECT OF HEAT-TREATMENT ON CARBON-ENCAPSULATED Fe_7C_3 NANOPARTICLES PREPARED BY EXPLOSION OF IRON-CONTAINING CARBONACEOUS XEROGEL

在1300℃、惰性气氛下,对含铁的炭基干凝胶的爆炸产物———无定型碳包裹Fe7C3纳米颗粒进行了热处理,并对热处理后的产物进行HRTEM和电子衍射分析。结果表明:热处理后无定型碳包裹Fe7C3纳米颗粒由10nm～40nm长大到100nm～300nm,颗粒的外层碳石墨化。通过对包裹颗粒的长大机理进行初步探索,认为在热处理过程中,核碳化铁对壳层的无定型碳具有催化石墨化作用;颗粒的长大是由于核Fe7C3对其外层的无定型碳产生催化石墨作用时,导致核碳化铁的裸露,相互融并引起的。

Amorphous carbonencapsulated Fe7C3 nanoparticles prepared through explosion of iron nitratecontaining carbonaceous xerogel were heattreated at 1?300?℃. The heattreated nanoparticles were studied by highresolution transmission electron microscopy and electron diffraction. The results show that the sizes of amorphous carbonencapsulated Fe7C3 nanoparticles increases from 10?nm～40?nm to 100?nm～300?nm and the structure of the shell changed from amorphous carbon to graphite. A mechanism reflecting these changes is proposed.