Fabrication and characterization of single phase cordierite honeycomb monolith with porous wall from natural raw materials as catalyst support
Fabrication and characterization of single phase cordierite honeycomb monolith with porous wall from natural raw materials as catalyst support
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DOI：
10.1016/j.ceramint.2014.11.009
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发表时间：
2015-04
影响因子：
5.2
通讯作者：
O. Al-Harbi;C. Özgür;M. M. Khan-M.
中科院分区：
文献类型：
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作者：
O. Al-Harbi;C. Özgür;M. M. Khan-M.
以沙特阿拉伯的高岭石和菱镁矿等天然原料为原料，不添加任何有机添加剂，采用挤压法制备了一种低成本、高孔率的单相堇青石蜂窝体。所实现的整料的表征集中在相评价和微观结构的发展取决于批料组合物和烧结条件。用X射线衍射、扫描电镜、红外光谱和热重分析等手段对样品的热膨胀系数、微观结构和晶体结构进行了表征。晶相也已通过Rietveld分析确定。结果表明，从化学成分和烧结温度两方面来看，合成单相堇青石的条件都非常狭窄。在任何烧结条件下，使用化学计量组成都不能获得单相堇青石。此外，低至5°C的烧结温度的变化也影响了结晶相。通过在1320°C下烧结非化学计量组成3小时，仅合成了单相堇青石，其中样品的线性热膨胀系数为2.07×10−6/°C。此外，在450 °C下热冲击300次循环后，所制造的整料保持其结构。
A low-cost, single phase cordierite honeycomb monolith whose walls are highly porous has been prepared by the extrusion method using local natural raw materials, as kaolinite and magnesite from Saudi Arabia without need of any organic additives. The characterization of the achieved monoliths has focused on the phase evaluations and microstructures development depending on batch compositions and sintering conditions. Thermal expansion coefficients, microstructures and crystalline structures of the obtained samples have been determined by X-ray diffraction, scanning electron microscopy, FT-IR and thermal dilatometry. Crystalline phases have been also determined by Rietveld analysis. The results show that, synthesis condition of single phase cordierite is extremely narrow by means of both chemical composition and sintering temperature. Single phase cordierite could not have been obtained by using stoichiometric composition for any sintering conditions. Also changing of the sintering temperature as low as 5°C has affected the crystalline phases. Only single phase cordierite has been synthesized by sintering the non-stoichiometric composition at 1320°C for 3 h where the linear thermal expansion coefficient of the sample is 2.07×10−6/°C. Also the fabricated monolith has kept its structure after thermal shock of 300 cycles at 450 °C.