摘要实验以五氧化二铌和氢氧化钠为原料，在水热反应釜中经过水热反应合成 NaNbO3 粉末。然后用离心机反复清洗反应产物，把过量的的氢氧化钠洗去，通过 X 射线衍射分析表明制备的粉末中，五氧化二铌没有剩余，得到纯净的铌酸钠粉末。 然后将铌酸钠与硫酸铜和氢氧化钠溶液以不同的比例混合均匀，氧化铜的质量分数 依次为 0,2‰，4‰，8‰，16‰。将混合后的粉末以 150MPa 压强压成直径 10mm 的薄片，在 1000oC 烧结 10h。对烧结后的陶瓷样品进行 X 射线衍射分析，通过阿 基米德排水法测量陶瓷片的密度，并用扫描电镜分析陶瓷片的表面形貌，最后使用 万用表和铁电仪测量分析陶瓷的介电性。79859

研究发现，所得到的粉末五氧化二铌完全转化为铌酸钠。硫酸铜和氢氧化钠混 合生成的氧化铜悬浊液，经离心机离心，可以与铌酸钠粉末均匀的混合在一起。添 加 CuO 比例为 2‰，4‰，8‰时，烧结后的试样主相为正交相 NaNbO3 同时还混有 杂相 Nb2O5 的相。当氧化铜添加比例为 16‰时，烧结后的样品只有铌酸钠相没有杂 相。随着加入的氧化铜含量的增加，晶界之间的空隙逐渐变小，晶粒变得相对规则 而且有所长大。随着氧化铜加入的量逐渐增多，其最大极化强度、剩余极化和矫顽 力也逐渐增大。其中氧化铜添加量为 8‰，16‰的样品存在漏电现象。

毕业论文关键词：无铅压电陶瓷；水热合成；铁电体；铌酸钠；CuO

Abstract NaNbO3 ceramic powders were synthesized by hydrothermal method from Nb2O5 and NaOH raw materials in an autoclave。 Then the reaction product was cleaned time  and again with the aid of centrifuge。 X-ray diffraction indicates the cleaned powders have single phase of NaNbO3 without any unreacted Nb2O5。 Then the NaNbO3 powders were

mixed with CuSO4  ang NaOH solution with different mass persent of CuO (0,2‰，4‰，

8‰，16‰)。 The mixed powders were pressed into pellets with 10mm diameter under 150MPa pressure and then sintered at 1000oC for 10h。 The phase structure of the sintered ceramics was identified by X-ray diffraction。 The density of the ceramics was measured

by the Archimedes drainage method。 The morphology of the surfaces of these ceramics were observed by scanning electron microscope。 Finally, their dielectric properties were measured with digital multimeter and an instrument for ferroelectric parameter measurement。

The study found the resulting powder is Nb2O5  complete conversion to NaNbO3。

CuSO4 and CuO in the NaOH suspension by centrifuging, can be uniformly mixed with the sodium niobate powder。Add CuO ratio of 2 ‰, 4 ‰, 8 ‰, the main sample after sintering phase quadrature phase NaNbO3 also mixed with the hetero phase Nb2O5 phase。 When the ratio of CuO added 16 ‰, the sample sintered only NaNbO3 phase no impurity phases。 With increasing content of CuO is added, and the gap between the grain boundary becomes smaller, the grain has grown and become relatively regular。 As the amount of CuO was added gradually increased, the maximum polarization, and remnant polarization coercivity also increases。 Wherein the CuO added in an amount of 8‰ and 16‰ sample leakage phenomenon exists。

Keywords: Lead-free piezoele ctricceramic; Hydrothermal synthesis; Ferroelectrics; NaNbO3;   CuO

目 录

第一章 绪论 1

1。1 引言 1

1。2 压电材料 1

1。2。1 压电材料释义