检索结果-南通市图书馆

Lanthanum-Neodymium-Co-Substituted Calcium Fluorobritholites

Journal of Materials Science and Chemical Engineering 2018年第7期6卷 151-162页

作者： mustapha hidouri Nawaf Albeladi Higher Institute of Applied Sciences and Technology of Gabes Gabes University Gabes Tunisia RU Catalysis and Materials for Environment and Process Engineering School Gabes University Gabes Tunisia Chemistry Department Faculty of Sciences Yanbu Taibah University Yanbu Al Bahr KSA

Britholites are considered as potential matrices for storage of nuclear wastes such as minor actinides and long-lived fission byproducts. This investigation is concerned with the study of simultaneous substitution in calcium fluor-britholite framework of two lanthanide ions assimilated to radionuclides. A series of calcium fluorbritholites doped with lanthanum and neodymium Ca8La2-xNdx(PO4)4(SiO4)2F2 with 0 ≤ x ≤ 2 were prepared via a solid state reaction in the temperature range 1450℃- 1250℃. The obtained products were characterized by several techniques such as Chemical analysis via Inductively coupled plasma Atomic emission spectrometry ICP-AES, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy FTIR and Nuclear magnetic resonance 31P NMR (MAS). Obtained solid solutions containing lanthanum and neodymium in variable proportions were typically apatite of hexagonal structure P63/m spatial group. The stoichiometry of the powders was verified via the metal/(phosphate + silicate) molar ratios found at about 1.67. The lattice parameters a and c calculated by the Rietveld method decreased as neodymium level increased. Despite, the close respective sizes of lanthanum and neodymium ions (VIrLa3+= 1.032A, VIrNd3+= 0.983A), their mutual substitutions led to solid solutions in whole range of composition with preferential occupation of Me (2) sites.

关键词： Calcium Fluorobritholites Lanthanum-Neodymium Ionic Substitutions

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Densification and Microstructure of Fluorapatite Sintered with Alkaline and Alkaline-Earth Additives

引用

Journal of Materials Science and Chemical Engineering 2018年第1期6卷 52-67页

作者： mustapha hidouri Faycal Ben Tahar Khaled Bouzouita Higher Institute of Applied Sciences Gabes University Gabes Tunisia RU Catalysis and Materials for Environment and Process Engineering School Gabes University Gabes Tunisia

A study was performed to investigate the effect of some selected sintering additives on the densification and microstructure of fluorapatite (FAp, Ca10(PO4)6F2). The sintering aids, used for improving the material densification at lower than 1080℃ temperature, were classified according to their cations as alkaline such as Li2CO3, NaF, Na2CO3, Na3PO4, KCl, K2CO3, and alkaline-earth such as CaF2, CaCl2 and MgCl2. Amounts of 0.1;1 and 3 wt% were vigorously homogenized with FAp powders then the solid mixture was pressurelessly sintered under argon flow with 10℃ .?min-1 heating and cooling speed. The density of each sintered material was determined by calculation of the pellet dimension and weight, the crystalline phases were identified using X-ray diffraction (XRD) and the phase morphology was examined by scanning electron microscopy (SEM). The dependence of densification and microstructure on sintering temperature range 900℃ - 1000℃ and amount of sintering aids was studied. It was found that all sintering additives were able to ameliorate the sintrability of the material at temperatures 900℃ and 1000℃. Maximums of about 96% were reached with adequate amounts and sintering temperatures. An exception was found with KCl which had no effect on the density. The microstructures of sintered specimens strictly follow the densification ratios and the sintering mechanism depended on the melting point of the additive.

关键词： Fluorapatite Sintering Additive Densification Microstructure

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：