Hesham I.Saleh
材料科学技术（英）
Calcium ferrite compounds were prepared using calcium nitrate and iron nitrate with different molar ratios, 1:1, 0.5:1, and 1:0.5, respectively. The reactions of formation were investigated at different temperatures following the differential thermal analysis (DTA) results. Calcium ferrite compounds are CaFeO3, Ca2FeO3.5, Ca2Fe2O5, CaFe2O4, CaFe4O7, Ca7.2F0.8Fe30O53, Ca3Fe15O25, Ca4Fe14O25, and Ca4Fe9O17. Other reactive species of calcium nitrate are still present after firing at 450ºC. Compounds were characterized using X-ray diffraction (XRD), DTA, TG, magnetic susceptibility, infrared spectra and scanning electron microscope (SEM). It is concluded that the formation mechanism of Ca-ferrite compounds depends mainly on the valency of iron cations which in role depends on its molar ratio and the existing atmosphere.
关键词:
Ca-ferrite
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null
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杨永珍
,
刘旭光
,
罗秋苹
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金琳
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许并社
新型炭材料
doi:10.1016/S1872-5805(09)60043-3
采用简单的空气氧化法由实心炭微球制备中空结构的炭微球.通过场发射扫描电子显微镜、高分辨透射电子显微镜、X-射线衍射仪、拉曼光谱和热重分析仪对产物的形貌和结构进行表征.结果表明:中空炭微球的石墨化程度较低.在炭微球的空气热氧化过程中,反应温度对炭微球从实心到中空的结构演变起着关键性的作用,温度越高,中空炭微球的内径越大、壁越薄.其形成机理可认为是炭微球的曲率和结晶度协同作用的结果.亦即,实心炭微球进行热氧化时,其内部的大曲率和低结晶度更易氧化,以致形成中空炭微球.
关键词:
炭微球
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氧化
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中空炭微球
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形成机理
毛永强
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胡美娜
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李娜
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李博君
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毛晶
人工晶体学报
先后利用化学气相沉积法和液相离子交换法,在FTO导电玻璃基底上两步法制备Cu2ZnSnS4 (CZTS)纳米片,并通过X射线衍射仪(XRD)、拉曼光谱仪(Raman)、扫描电镜(SEM)、透射电镜(TEM)、X射线能谱(EDS)和紫外-可见吸收光谱仪(UV-vis)等表征手段对所得样品的物相结构、微观形貌、化学组分及光学性能进行测试分析.研究结果表明,所得样品为四方晶型CZTS纳米片,对可见光具有良好的全波段吸收,经计算其禁带宽度约1.51 eV.此外,对CZTS纳米片的形成机理进行初步探讨.
关键词:
Cu2ZnSnS4
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纳米片
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光学性能
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禁带宽度
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形成机理
