The Fe-Si mechanical alloying and its transformation are investigated to evaluate whether mechanical alloying is a useful process for producing Fe-Si alloy. The mechanical alloying process of Fe-Si powders is studied ...The Fe-Si mechanical alloying and its transformation are investigated to evaluate whether mechanical alloying is a useful process for producing Fe-Si alloy. The mechanical alloying process of Fe-Si powders is studied by SEM（ scanning electron microscopy）, EDS（energy dispersive spectrometer）and XRD（X-ray diffraction）. The results show that the ball milling process first makes tough Fe powder a lump structure and brittle Si powder a small particle, and then as the mill power increases, the tough powder of iron with a lamellar structure forms and the Si particles lies on or between the Fe lamellas. Finally, the Fe and Si powders are mechanically alloyed through atom diffusion. So the Fe and Si powders can be alloyed by 15 h ball milling at a speed of 400 r/min and with a ball-to-powder ratio of 40 ： 1. After heating at 1 243 K for 1 h, the milled powders transform to α-FeSi2, and after heating at 1 243 K for 1 h, then cooling to 1 073 K for 1 h, the milled powders transform to β-FeSi2. Therefore, the monophase α-FeSi2 or β-FeSi2 can be obtained by heat treatment of mechanically alloyed Fe-Si powders.展开更多
Bulk single crystals β-FeSi2, as a new photoelectric and thermoelectric material, has been successfully grown using chemical vapor transport techniqueby using iodine as transport agent in a sealed ampoule. The effect...Bulk single crystals β-FeSi2, as a new photoelectric and thermoelectric material, has been successfully grown using chemical vapor transport techniqueby using iodine as transport agent in a sealed ampoule. The effects of crystal growth condition on quality and morphologies of the single crystals were studied. Both needle-like and grain-like single crystals were gained. By changing substrate temperature, tetrahedral high quality α-FeSi2 single crystals were also obtained.展开更多
文摘The Fe-Si mechanical alloying and its transformation are investigated to evaluate whether mechanical alloying is a useful process for producing Fe-Si alloy. The mechanical alloying process of Fe-Si powders is studied by SEM（ scanning electron microscopy）, EDS（energy dispersive spectrometer）and XRD（X-ray diffraction）. The results show that the ball milling process first makes tough Fe powder a lump structure and brittle Si powder a small particle, and then as the mill power increases, the tough powder of iron with a lamellar structure forms and the Si particles lies on or between the Fe lamellas. Finally, the Fe and Si powders are mechanically alloyed through atom diffusion. So the Fe and Si powders can be alloyed by 15 h ball milling at a speed of 400 r/min and with a ball-to-powder ratio of 40 ： 1. After heating at 1 243 K for 1 h, the milled powders transform to α-FeSi2, and after heating at 1 243 K for 1 h, then cooling to 1 073 K for 1 h, the milled powders transform to β-FeSi2. Therefore, the monophase α-FeSi2 or β-FeSi2 can be obtained by heat treatment of mechanically alloyed Fe-Si powders.
基金the National Natural Science Foundation of China(Grant No.50171077)863 project
文摘Bulk single crystals β-FeSi2, as a new photoelectric and thermoelectric material, has been successfully grown using chemical vapor transport techniqueby using iodine as transport agent in a sealed ampoule. The effects of crystal growth condition on quality and morphologies of the single crystals were studied. Both needle-like and grain-like single crystals were gained. By changing substrate temperature, tetrahedral high quality α-FeSi2 single crystals were also obtained.
