Local and Extended-Order Evolution of Synthetic Talc during Hydrothermal Synthesis: Extended X-ray Absorption Fine Structure, X-ray Diffraction, and Fourier Transform Infrared Spectroscopy Studies

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• 作者：Angela Dumas ; Mart铆n Mizrahi ; Fran莽ois Martin ; Felix G. Requejo
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：November 4, 2015
• 年：2015
• 卷：15
• 期：11
• 页码：5451-5463
• 全文大小：763K
• ISSN：1528-7505

文摘

Synthetic talc is a new filler of industrial interest due to its submicron size, its chemical and mineral purity, and its hydrophilic character. To develop this filler on a preindustrial scale, this work aimed to understand the mechanisms of transformation from the amorphous talc precursor to crystalline synthetic talc. X-ray diffraction, Fourier transform infrared spectroscopy, and extended X-ray absorption fine structure at Ni鈥揔 edge techniques were used to study a Ni-talc series composed of a talc precursor sample and talc samples synthesized at 100, 200, and 300 掳C for 1 or 6 h. As soon as the Ni-talc precursor precipitated, a tetrahedral鈥搊ctahedral鈥搕etrahedral-type structure appeared that was characterized by 2鈥? Ni-octahedra distanced 3.07 脜 from each other and by 3鈥? Si tetrahedra distributed on the top and bottom of the octahedral 鈥渟heet鈥?and distanced 3.29 脜 from Ni. Simultaneously following the synthesis temperature, the octahedral sheet grew, and the tetrahedral sheet expanded; the distances Ni鈥揘i and Ni鈥揝i also gradually shortened. The intracrystalline distribution of the octahedral sheet was also studied. At 300 掳C, a random distribution was obtained. Cluster distribution was not observed at low temperature, which we hypothesize is a function of crystallite size.