Metal zirconium phosphate macroporous monoliths: Versatile synthesis, thermal expansion and mechanical properties
Metal zirconium phosphate macroporous monoliths: Versatile synthesis, thermal expansion and mechanical properties
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DOI：
10.1016/j.micromeso.2015.12.002
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发表时间：
2016-05
影响因子：
5.2
通讯作者：
Yang Zhu;K. Kanamori;Nirmalya Moitra;K. Kadono;S. Ohi;N. Shimobayashi;K. Nakanishi
中科院分区：
文献类型：
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作者：
Yang Zhu;K. Kanamori;Nirmalya Moitra;K. Kadono;S. Ohi;N. Shimobayashi;K. Nakanishi
采用溶胶-凝胶相分离法制备了金属磷酸锆（MZP）大孔整体材料。通过简单地将目标金属盐加入到优化的起始溶液中，合成了30多种具有双连续大孔结构的MZP单块多晶材料。由于其高沸点，甘油作为溶剂起着关键作用，以防止金属盐重结晶，从而允许金属盐均匀分布在聚合磷酸锆网络上。在1000 °C下煅烧该干凝胶，得到了多级多孔的多晶磷酸锶锆（SrZrP）单块。极低的热膨胀（热膨胀系数（CTE）为1.4 × 10− 6 K −1），温度范围宽（38 °C-1000 °C）同时具有良好的机械性能（三点弯曲试验的弯曲模量为8.0 GPa，单轴压缩试验的杨氏模量为1.9 GPa），而由于大孔的存在而导致的高孔隙率（43%）降低了堆积密度。与相同组成的致密陶瓷相比，CTE值较低，并且可以归因于纳米尺寸的小孔的存在，其在升高的温度下吸收大孔骨架中的每个微晶的各向异性热膨胀。
A versatile synthetic method has been developed for the fabrication of metal zirconium phosphate (MZP) macroporous monoliths via a sol–gel process accompanied by phase separation. More than 30 kinds of MZP monolithic polycrystalline monoliths with co-continuous macroporous structure have been synthesized by simply adding the target metal salt in the starting solution with optimized compositions. Glycerol, due to its high boiling point, plays the key role as the solvent to prevent metal salt from recrystallization, allowing a homogeneous distribution of metal salts over the polymerizing zirconium phosphate network. Hierarchically porous polycrystalline strontium zirconium phosphate (SrZrP) monolith has been obtained when the dried gel was calcined at 1000 °C. Very low thermal expansion (coefficient of thermal expansion (CTE) as 1.4 × 10−6K−1) over a wide temperature range (38 °C–1000 °C) together with good mechanical properties (flexural modulus as 8.0 GPa from 3 point bending test and Young's modulus as 1.9 GPa from uniaxial compression test) has been demonstrated, while high porosity (43%) due to the presence of macropores reduces bulk density. As compared with dense ceramics of the same composition, the CTE value is lower and can be attributed to the presence of nanometer-sized small pores, which absorbs the anisotropic thermal expansion of each crystallite in the macropore skeletons at elevated temperatures.