【作者】 刘斌；

【导师】 柯华；

【作者基本信息】 哈尔滨工业大学 ， 材料与化工（专业学位）， 2025， 硕士

【摘要】 电子功能材料和磁性功能材料在当今信息化、智能化的社会中占据主导地位。然而,以磁电复合材料为核心的能量转换器在应用市场上并未得到广泛使用,其主要问题是磁电界面的稳定性差、持久性差以及应力传递效率低,如何改善界面连接问题是本领域的研究难点。针对上述问题,本文设计了一种（1-x）Pb Zr_0.52Ti_0.48O₃-x Co Fe₂O₄镶嵌式复合陶瓷,并在界面处实现了共格连接,提高了材料磁电耦合系数。本课题从粉体的晶化行为、陶瓷的烧结致密化过程、陶瓷界面结构和陶瓷磁电性能进行系统的研究。通过溶胶凝胶的方法合成了均匀稳定的PZT-CFO复相陶瓷。干凝胶的主要成分为硝酸铅。煅烧干凝胶过程中,有机物分解温度在200～600℃,并断定CFO结晶温度在294℃,PZT结晶温度在644℃。采用两步法煅烧工艺,得到了原位自分离的两相复合陶瓷粉体。通过对复相陶瓷的烧结工艺的优化,1100℃烧结2 h的陶瓷晶粒大小均匀,磁性相分布均匀且具有镶嵌式结构。两相界面通过共格连接,界面的应力使得附近晶面发生弯曲,范围为10～20个晶面间距,并使得700 cm^-1拉曼峰位向低波数方向发生偏移。烧结温度在1100℃以下时,陶瓷的介电常数较低;烧结温度在1100℃以上,陶瓷介电常数基本相当,为600左右。随着CFO含量的增加,材料的弛豫性逐渐增强。过长的保温时间和过高的烧结温度会导致Pb O挥发严重,介电常数下降。施加的极化电场越大,陶瓷在谐振频率处的电学响应越明显。CFO含量5%的陶瓷达到最大d₃₃=149 p C/N。制备的分段煅烧复合陶瓷磁矩在1000 Oe内均能达到饱和,在CFO含量为5%的陶瓷中,共格界面降低了材料磁矩;相比一次煅烧的陶瓷,磁电耦合性能提升30%,增大了界面应力传递效率。以此为基础制备的磁电传感器在谐振频率处可检测45μT磁场,磁场大小灵敏度为22μT,频率灵敏度大于10 Hz。更多还原

【Abstract】 Electronic functional materials and magnetic functional materials occupy a dominant position in today’s informationized and intelligent society.However,the energy converter with magneto-electric composites as the core is not widely used in the application market,and its main problems are the poor stability and durability of the magneto-electric interface as well as the low efficiency of the stress transfer,and how to improve the interfacial connection problem is a research difficulty in this field.To address the above problems,this paper designs a（1-x）Pb Zr_0.52Ti_0.48O₃-x Co Fe₂O₄ mosaic composite ceramics,and realizes the common-lattice connection at the interface,which improves the magnetoelectric coupling coefficient of the material.This topic is systematically investigated from the crystallization behavior of the powder,the sintering densification process of the ceramic,the ceramic interface structure and the ceramic magnetoelectric properties.Uniformly stabilized PZT-CFO complex-phase ceramics were synthesized by sol-gel method.The main component of the dry gel was lead nitrate.During the calcination of the dry gel,the decomposition temperature of the organic matter was200～600℃,and it was concluded that the crystallization temperature of CFO was294℃and that of PZT was 644℃.The two-step calcination process was used to obtain in situ self-separated two-phase composite ceramic powders.Through the optimization of the sintering process of the complex ceramics,the ceramic grains sintered at 1100℃for 2 h were uniform in size,and the magnetic phases were uniformly distributed and had a mosaic structure.The two-phase interface is connected by a common lattice,and the stress at the interface causes bending of the nearby crystal surfaces in the range of 10-20 crystal spacings,and shifts the Raman peak position at 700 cm^-1 to the direction of low wave number.The ceramics have low dielectric constants at sintering temperatures below1100°C.Above 1100°C,the ceramic dielectric constants are essentially comparable at about 600.With the increase of CFO content,the relaxation of the material gradually increases.Excessively long holding time and high sintering temperature lead to serious volatilization of Pb O and a decrease in the dielectric constant.The larger the applied polarization electric field,the more pronounced the electrical response of the ceramics at the resonance frequency.The ceramics with 5%CFO content reach a maximum d₃₃=149 p C/N.The magnetic moments of the prepared segmented calcined composite ceramics are saturated up to 1000 Oe,and the co-lattice interface reduces the magnetic moments of the materials in ceramics with a CFO content of 5%;compared with ceramics calcined in a single pass,the magneto-electric coupling performance is improved by 30%,and the interfacial stress transfer efficiency is enlarged.The magnetoelectric sensor prepared on this basis can detect a magnetic field of 45μT at the resonance frequency with a magnetic field magnitude sensitivity of 22μT and a frequency sensitivity greater than 10 Hz.更多还原