溶胶—凝胶法制备NiCuZn铁氧体薄膜和粉体的研究

发布时间：2018-05-31 04:43

本文选题：溶胶 + 凝胶　；参考：《兰州大学》2010年硕士论文

【摘要】：NiCuZn软磁铁氧体具有电阻率大、涡流损耗小、成本低等优点,其使用频率范围是kHz到将近GHz,宽于MnZn (1MHz以下)和NiZn (1-100MHz)铁氧体材料,可以实现高频射频信号的能量传输和阻抗转换,广泛应用于计算机、电视、通讯等领域,主要用于制造电感等元器件,但是到目前为止,成功应用于集成电路的高频NiCuZn软磁铁氧体薄膜的制备和研究还较少,能否成功的制备出高饱和磁化强度、低矫顽力的NiCuZn铁氧体薄膜成为未来其应用的一个重要限制因素。在制备薄膜材料的工艺方法中,常用的有溅射、真空蒸发等工艺。但是溅射方法制备薄膜工艺存在各离子溅射速率不同造成成份偏析以及沉积速率低等缺点,真空蒸发也存在重复性差和附着性差等缺点,而且铁氧体的高熔点使得真空蒸发工艺的具体实施存在困难。然而另一种制备薄膜的常见方法-溶胶-凝胶旋涂法制备铁氧体薄膜的报道还比较少。溶胶-凝胶工艺因为其可以使反应物达到分子水平的混合、容易控制成分、有效的降低烧结温度等优点,广泛应用于材料科学和陶瓷工艺领域。凝胶可以应用旋涂法在基片上做膜,其优点是条件简单,并且不受物体外形的限制。本文应用溶胶-凝胶旋涂工艺进行了NiCuZn软磁铁氧体的粉体和薄膜的制备,采用N,N二甲基甲酰胺作为溶剂,聚乙烯吡咯烷酮作为表面活性剂,研究了成分配比、溶胶凝胶性质,以及工艺条件等对粉体和薄膜磁性能的影响,在制备出磁性能优异的NiCuZn软磁铁氧体粉体材料薄膜方面做了积极的探索并获得了一些有意义的结果。 1.将稳定的凝胶在常温下自蔓延燃烧,所得到的前驱粉体在≥750℃下处理,将会生成比较纯的尖晶石相。而相应成份的薄膜在400℃进行长时间热处理,没有尖晶石相生成,当热处理温度达到600℃左右,即能生成完全的尖晶石相。 2.采用适当缺铁配方的Ni0.4Cu0.2Zn0.4Fe1.9O4制得的粉体,在900℃下保温三个小时,矫顽力可达90e,饱和磁化强度为72.4 emu/g,继续升高温度,当温度达到1000℃,此时样品的矫顽力为50e,饱和磁化强度为73.57 emu/g。 3.与未加入醋酸的溶胶相比,加入适量醋酸调节pH值为3.2时,在Si基片上得到的薄膜样品矫顽力较小,可见加酸得到的凝胶的活性更高。 4.将溶胶在不同温度下陈化,制得样品的矫顽力Hc随溶胶陈化放置时间逐渐减小,然后趋于稳定,其中由常温下放置的溶胶制得样品的矫顽力较小且最先稳定。 5.为制得高性能的薄膜样品,应采用Ni0.4Cu0.2Zn0.4Fe2O4的正配比配方,有利的烧结工艺是在500℃-650℃之间,进行短时间的保温,抑制晶粒生长,其中处理温度585℃的样品,矫顽力达到160e,在更高的温度下,矫顽力和饱和磁化强度都将升高,饱和磁化强度在较高的温度可以达到300 emu/cm3。 6.测量较高的温度下处理粉体和薄膜,测得的电子自旋共振谱中谱线会改变,曲线与横坐标的交点反映出的g值的变化,意味着离子之间占位发生改变。这可能与应用溶胶-凝胶离子与很高的活性,适当的高温将导致Zn元素挥发,导致尖晶石铁氧体A位缺失的Zn离子将被其他离子取代有关。
[Abstract]:NiCuZn soft ferrite has the advantages of large resistivity, small eddy current loss and low cost. The use frequency range is from kHz to near GHz, wider than MnZn (1MHz) and NiZn (1-100MHz) ferrite material. It can realize the energy transmission and impedance conversion of high frequency radio frequency signal. It is widely used in the fields of computer, television, communication and so on. It is mainly used in manufacturing. Inductance and other components, but so far, the preparation and research of the high frequency NiCuZn soft ferrite thin films which have been successfully applied to the integrated circuits are still less. The successful preparation of high saturation magnetization and the low coercive force of NiCuZn ferrite thin film become a key limiting factor in future applications. Sputtering, vacuum evaporation and other processes are commonly used in the process. However, there are disadvantages of different sputtering rates and low deposition rate, such as low ion sputtering rate and low deposition rate. The vacuum evaporation also has the disadvantages of poor repeatability and poor adhesion, and the high melting point of ferrite makes the specific implementation of vacuum evaporation process difficult. However, another common method for preparing thin films - sol-gel spin coating method for preparing ferrite thin films is still less. The sol-gel process is widely used in the field of material science and ceramic technology because it can make the reactants at molecular level, easily control components, and reduce the sintering temperature effectively. With the application of spin coating on the substrate, the advantage is that the condition is simple and it is not restricted by the shape of the object. In this paper, the preparation of the powder and film of NiCuZn soft ferrite was prepared by the sol-gel spin coating process. N, N two methyl formamide was used as the solvent and polyvinylpyrrolidone was used as a surface active agent. The effects of gel properties and technological conditions on the magnetic properties of powders and films have been actively explored and some meaningful results have been obtained in the preparation of NiCuZn soft magnetic ferrite powder materials with excellent magnetic properties.
1. the stable gel is self propagating at normal temperature. The obtained precursor powder is treated at more than 750 degrees C, and a relatively pure spinel phase will be generated. The film of the corresponding component will be heat treated at 400 C for a long time, without the formation of the spinel stone phase, and the complete spinel phase can be generated when the heat treatment temperature reaches the left right of 600 C.
2. the powder obtained by Ni0.4Cu0.2Zn0.4Fe1.9O4 with proper iron deficiency formula is kept at 900 C for three hours, the coercive force can reach 90E, the saturation magnetization is 72.4 emu/g, and the temperature continues to rise. When the temperature reaches 1000, the coercive force of the sample is 50E, and the saturation magnetization is 73.57 emu/g..
3. compared with the sols without acetic acid, when a proper amount of acetic acid is added to the pH value of 3.2, the film samples obtained on the Si substrate are less coercive, and the activity of the gel obtained with acid is higher.
4. the sols are aging at different temperatures, and the coercive force Hc of the samples decreases gradually with the sol-aging time, and then tends to be stable, in which the coercivity of the samples obtained by the sols placed under the normal temperature is smaller and the first stable.
5. for the preparation of high performance film samples, the positive ratio formula of Ni0.4Cu0.2Zn0.4Fe2O4 should be used. The favorable sintering process is between 500 C and -650 C for short time heat preservation and inhibition of grain growth, in which the samples with temperature 585 C and the coercive force reach 160E, the coercive force and saturation magnetization will be increased at a higher temperature and full saturation magnetization will be increased. And magnetization can reach 300 emu/cm3. at higher temperature.
6. at a higher temperature, the powder and the film are treated. The spectra line in the electron spin resonance spectrum will be changed, the change of the g value reflected by the intersection point between the curve and the abscissa means the change of the occupying position between the ions. This may be associated with the application of the sol-gel ion and high activity. The appropriate high temperature will lead to the volatilization of the Zn element and lead to the spinel. The Zn ions with A deletion in the ferrite will be replaced by other ions.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TM277

【参考文献】