Low Temperature Synthesis of Porous NZP Ceramics
Low Temperature Synthesis of Porous NZP Ceramics
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DOI：
10.1111/j.1551-2916.2008.02377.x
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发表时间：
2008-06
影响因子：
3.9
通讯作者：
J. V. Bothe;P. Brown
中科院分区：
文献类型：
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作者：
J. V. Bothe;P. Brown
多孔相纯 NaZr2(PO4)3 整体材料是在 850°C 下由混合水溶性前体而沉淀的凝胶合成的。烧结温度限制在 850°C，以允许在 NZP 表现出低热膨胀系数的范围内进行致密化。人们尝试通过物理和化学手段来最大化机械性能。将颗粒状羟基磷灰石 (HAp) 与沉淀的凝胶物理混合以模拟 NZP 的结晶。将硝酸铜溶解在溶液中作为烧结助剂以刺激烧制过程中的液相烧结。不含这些添加剂的 NZP 的比表面积达到 30 m2/g。添加 HAp 将内表面积降低至 5 m2/g。 X射线衍射和扫描电子显微镜没有检测到烧制样品中HAp的存在，表明它在烧制过程中已被消耗。硝酸铜分解为 CuO，其作为烧结助剂的存在导致致密化增强和强度提高。 5% CuO（硝酸铜）和 5% HAp 的存在导致烧制过程中体积收缩 40%。该组合物获得的拉伸强度为20MPa，而没有添加剂烧制的组合物获得的拉伸强度约为8MPa。
Porous phase-pure NaZr2(PO4)3 monoliths were synthesized at 850°C from gels that precipitated as a consequence of mixing water-soluble precursors. The sintering temperature was limited to 850°C to permit densification in a range where NZP exhibits a low coefficient of thermal expansion. Attempts to maximize mechanical properties were made by both physical and chemical means. Particulate hydroxyapatite (HAp) was physically blended with the precipitated gels to template the crystallization of NZP. Copper nitrate was dissolved into solution as a sintering aid to stimulate liquid-phase sintering during firing. NZP made without these additives attained a specific surface area of 30 m2/g. The addition of HAp reduced the internal surface area to 5 m2/g. X-ray diffraction and scanning electron microscopy did not detect the presence of HAp in the fired samples, indicating it had been consumed during firing. Copper nitrate decomposed to CuO and its presence as a sintering aid resulted in enhanced densification and greater strengths. The presence of 5% CuO (as copper nitrate) together with 5% HAp resulted in a 40% volume shrinkage during firing. The tensile strength attained for this composition was 20 MPa as compared with that of approximately 8 MPa for the compositions fired without additives.