以MoSi2和(NH4)6Mo7O24·4H2O为原料,在酸性环境中,采用液相沉淀法制备Mo-MoSi2前驱体粉末,并对得到的前驱体粉末采用氢气热还原法制备Mo-MoSi2复合粉末.借助X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱分析(EDS)分析检测手段研究沉积条件(钼源浓度、反应温度、HCl添加量)对前驱体粉末的成分、物相组成与微结构的影响,并分析热还原后所得粉末的物相组成.结果表明:当钼源浓度为0.0142和0.0285 mol·L-1时,前驱体粉末由MoO3和MoSi2两相组成;当钼源浓度增大到0.0570 mol·L-时,前驱体粉末中没有形成MoO3;随着反应温度的升高或HCl添加量的增加,由六棱柱MoO3组装而成的微米支状结构的数量逐渐增多,并且团聚程度也随之增加.研究同时发现,在整个前驱体粉末制备过程中,H+的量对MoO3的形成起决定性的作用.还原后的粉末主要是由Mo和MoSi2两相组成,同时还含有少量的Mo2C.
Using MoSi2 and (NH4)6 Mo7O24·4H2O as raw materials,Mo-MoSi2 composite powder precursors were prepared by liquid precipitation and Mo-MoSi2 composite powder was prepared by reduction of the precursor.Effects of the concentration of (NH4)6Mo7O24,reaction temperature and the content of HCl on composition,phase and microstructure of the precursors were investigated by X-ray diffraction (XRD),scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS).The composition of as-prepared Mo-MoSi2 composite powder was studied.The results showed that the compositions of the precursors,which were prepared by 0.0142 and 0.0285 mol·L-1 (NH4) 6 Mo7O24,respectively,were made of MoO3 and MoSi2 phases.No MoO3 was detected in the precursor prepared by 0.0570 mol·L-1 (NH4)6 Mo7O24.With the increase of reaction temperature and the content of HCl,the number of micron branched structure assembled with MoO3 and the agglomeration of particles increased.H + played a critical role in the formation of MoO3.The reduced powder was composed of Mo,MoSi2 and minor Mo2C.
参考文献
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%