The anatase-rutile phase transformation of TiO_2 doped cerium up to 5 molpercent was studied by X-ray diffraction and X-ray photoelectron spectroscopy. The samples wereprepared by sol-gel auto-igniting synthesis proce...The anatase-rutile phase transformation of TiO_2 doped cerium up to 5 molpercent was studied by X-ray diffraction and X-ray photoelectron spectroscopy. The samples wereprepared by sol-gel auto-igniting synthesis process from a TiO(NO_3)_2-Ce(NO_3)_2-NH_4NO_3-citricacid complex compound system. The combusted amorphous powders were calcined at differenttemperatures. Significant structural changes were observed during the various stages of the phasetransformation. It was concluded that at low dopant contents, cerium ions were incorporated into theTiO_2 structure, and the anatase phase was stabilized; but at larger amounts, part of the dopantwas segregated on the surface of TiO_2 and the rutile formation was accelerated at elevatedcalcination temperature.展开更多
The grinding of ultra-fine talcum powder and its application in a polypropylene （PP） matrix were investigated. Ultra-fine talcum powder was prepared by adjusting the grinding parameters of the physical milling proce...The grinding of ultra-fine talcum powder and its application in a polypropylene （PP） matrix were investigated. Ultra-fine talcum powder was prepared by adjusting the grinding parameters of the physical milling process. The talcum powder exhibited polymodal distribution. The layered morphology of talcum particles in a horizontal sand mill was rarely damaged or destroyed. PP-talcum nanocomposites were prepared by melt blending using a twin-screw extruder. Nano talcum can be seen as a single particle, although it is not very apparent. The bending strength of talcum-filled PP was gradually increased by approximately 28%. The impact strength linearly decreased as the filler weight ratio increased. The overall maximum improvement in mechanical properties was recorded when the filler ratios increased from 15 wt% to 20 wt%.展开更多
文摘The anatase-rutile phase transformation of TiO_2 doped cerium up to 5 molpercent was studied by X-ray diffraction and X-ray photoelectron spectroscopy. The samples wereprepared by sol-gel auto-igniting synthesis process from a TiO(NO_3)_2-Ce(NO_3)_2-NH_4NO_3-citricacid complex compound system. The combusted amorphous powders were calcined at differenttemperatures. Significant structural changes were observed during the various stages of the phasetransformation. It was concluded that at low dopant contents, cerium ions were incorporated into theTiO_2 structure, and the anatase phase was stabilized; but at larger amounts, part of the dopantwas segregated on the surface of TiO_2 and the rutile formation was accelerated at elevatedcalcination temperature.
基金Funded by the Foundation of Shanghai Science and Technology Committee (Nos.10521100602, 10DZ2211400)Foundation of Guangdong Province (No.2011A090200082)China Postdoctoral Science Foundation, and Research Foundation for the Excellent Youth Scholars of Shanghai(No.SHU-10057)
文摘The grinding of ultra-fine talcum powder and its application in a polypropylene （PP） matrix were investigated. Ultra-fine talcum powder was prepared by adjusting the grinding parameters of the physical milling process. The talcum powder exhibited polymodal distribution. The layered morphology of talcum particles in a horizontal sand mill was rarely damaged or destroyed. PP-talcum nanocomposites were prepared by melt blending using a twin-screw extruder. Nano talcum can be seen as a single particle, although it is not very apparent. The bending strength of talcum-filled PP was gradually increased by approximately 28%. The impact strength linearly decreased as the filler weight ratio increased. The overall maximum improvement in mechanical properties was recorded when the filler ratios increased from 15 wt% to 20 wt%.
