수소화기상증착공정을 이용한 마그네슘하이드라이드 미세분말 합성

Abstract

This work describes the hydriding chemical vapor synthesis (HCVS) of the <TEX>$MgH_2$</TEX> in a hydrogen atmosphere and the product's hydriding-dehydridng properties. Mg powder was used as a starting material to synthesize <TEX>$MgH_2$</TEX> and uniformly heated to a temperature of <TEX>$600^{\circ}C$</TEX> for Mg vaporization. The effects of hydrogen pressure on the morphology and the composition of HCVS-<TEX>$MgH_2$</TEX> were examined by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is clearly seen that after the HCVS process, the particle size of synthesized <TEX>$MgH_2$</TEX> was drastically reduced to the submicron or micrometer-scale and these showed different shapes (needle-like nanofibers and angulated plate) depending on the hydrogen pressure. It was found that after the HCVS process, the <TEX>$H_2$</TEX> desorption temperature of HCVS-<TEX>$MgH_2$</TEX> decreased from 380 to <TEX>$410^{\circ}C$</TEX>, and the minimum hydrogen desorption tempreature of HCVS-<TEX>$MgH_2$</TEX> powder with needle-like shape can be obtained. In addition, the enhanced hydrogen storage performance for needle-like <TEX>$MgH_2$</TEX> was achieved during subsequent hydriding-dehydriding cycles.