Low-temperature synthesis of SrAl₂O₄ by a modified sol–gel route: XRD and Raman characterization

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• 作者：Purificació ; n Escribano ; Mó ; nica Marchal ; Mar&#xed ; a Luisa Sanju&#xe1 ; n ; Pablo Alonso-Guti&#xe9 ; rrez ; Beatriz Juli&#xe1 ; n and Eloisa Cordoncillo
• 关键词：Sol– ; gel ; Pechini's method ; Aluminates ; Raman spectroscopy
• 刊名：Journal of Solid State Chemistry
• 出版年：2005
• 期刊代码：130_00224596
• 类别：ch
• 出版时间：2005
• 卷：178
• 期：6
• 页码：1978-1987
• 文件大小：485 K

摘要

Among other alkaline-earth aluminates, the monoclinic (M) polymorph of SrAl₂O₄ can be used as host material for Eu²⁺ luminescence based phosphors. With the aim of reducing the synthesis temperature of this polymorph, we have produced and characterized by XRD and Raman scattering solid solutions of the SrAl_2−xB_xO₄ system (me="mml12">method=retrieve&_udi=B6WM2-4G361TM-3&_mathId=mml12&_user=10&_cdi=6922&_rdoc=33&_handle=V-WA-A-W-ZU-MsSAYZA-UUW-U-AABZBDCAZC-AABBECCEZC-CAYEZYDDV-ZU-U&_acct=C000050221&_version=1&_userid=10&md5=82c54fb6ded43dabc03e9c79e4afe856" title="Click to view the MathML source">xmg src="http://www.sciencedirect.com/scidirimg/entities/2a7d.gif" alt="less-than-or-equals, slant" border=0>0.3) obtained by two different methods, a ceramic route and a modified sol–gel synthesis. Though the addition of boron lowers the temperature of obtention of the M polymorph in both type of samples, lower B contents are needed to stabilize the M form as single phase for samples prepared by the sol–gel method than through the ceramic route. In the sol–gel method, the M polymorph can be obtained at temperatures as low as 1200 °C, with a Boron content of just 1%. Rietveld profile analysis allows us to conclude that coexistence of the monoclinic and hexagonal polymorphs of SrAl₂O₄ occurs for samples synthesized below an onset temperature of about 1000–1100 °C, that depends on the sample composition. Above those temperatures, only the monoclinic phase is formed.