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借助XRD、SEM和能谱分析仪等手段,研究了1 600℃煅烧中低品位矾土制备的钛酸铝/莫来石(Al_2TiO_5ss/3Al_2O_3·2SiO_2ss)复合材料经1 200℃保温12h后结构的稳定性。结果表明:高温煅烧中低品位矾土后,其合成材料的结晶物相组成为3Al_2O_3·2SiO_2ss、Al_2TiO_5ss和少量残存的方石英;Fe~(3+)或Ti~(4+)离子以不同形态赋存于结晶相(3Al_2O_3·2SiO_2ss和Al_2TiO_5ss)和非晶相。含Fe~(3+)/Ti~(4+)离子的3Al_2O_3·2SiO_2ss将Al_2TiO_5ss结晶相分割,使其蜷缩其间,并抑制Al_2TiO_5ss的分解;高温下,二者因组成元素相近而致使晶界融合,进而共同构建了体系牢固的致密骨架结构。由3Al_2O_3·2SiO_2ss和Al_2TiO_5ss等高温物相构成的致密结构将非晶相挤压于空隙结构的3Al_2O_3·2SiO_2ss晶间,避免了低熔点相富集带来的不利影响,进而赋予该Al_2TiO_5ss/3Al_2O_3·2SiO_2ss复合材料良好的结构稳定性。
By means of XRD, SEM and EDS, the structure of Al 2 TiO 5 S 3 Al 2 O 3 · 2SiO 2ss composites prepared by low-grade bauxite calcined at 1 600 ℃ for 12h at 1200 ℃ was studied. stability. The results show that the phase composition of the synthesized materials is 3Al_2O_3 · 2SiO_2ss, Al_2TiO_5ss and a small amount of cristobalite calcined at low temperature. The Fe 3+ or Ti 4+ ions have different morphologies, Occur in the crystalline phase (3Al_2O_3 · 2SiO_2ss and Al_2TiO_5ss) and the amorphous phase. 3Al_2O_3 · 2SiO_2ss containing Fe ~ (3 +) / Ti ~ (4 +) ions segregates the crystalline phase of Al_2TiO_5ss, curling it and inhibiting the decomposition of Al_2TiO_5ss. At high temperature, , And then together to build a solid system of dense skeleton structure. The dense structure consisting of 3Al_2O_3 · 2SiO_2ss and Al_2TiO_5ss and other high-temperature phases extrudes the amorphous phase into the interstitial 3Al_2O_3 · 2SiO_2ss intergranular and avoids the unfavorable effects of low-melting phase enrichment, which in turn gives the Al_2TiO_5ss / 3Al_2O_3 · 2SiO_2ss Composites Good Structural Stability.