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|Type:||Artigo de periódico|
|Title:||Genesis Of A Solid Foam: Iron(iii) Metaphosphate Transformation In Sol-gel Crystallization Processes|
|Author:||De Abreu Filho P.P.|
Da Silva E.C.
|Abstract:||Poorly crystalline iron(III) metaphosphate (IMP) is obtained by admixture of iron nitrate and sodium metaphosphate aqueous solutions. Under heating, this solid undergoes various transformations, which were followed by X-ray diffraction, IR spectrophotometry, ESR spectroscopy, surface area, and density and weight loss determinations. At least three different crystalline phases are formed, at different stages; crystalline and noncrystalline phases coexist, in many situations. IMP yields a solid, rigid foam under heating to t > 620°C and a glass at t ≃ 1200°C. Foam formation is explained, by use of the experimental data, as a result of concurrent water release, gaseous cell formation, and crystallization of the solid mass, without simultaneous fragmentation. © 1990 American Chemical Society.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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