铁基磁屏蔽梯度复合结构材料制备与屏蔽性能研究
发布时间：2018-08-16 12:52
【摘要】：现代仪器和设备所处的电磁环境日趋复杂,对屏蔽材料提出了更加苛刻的要求。本文以提高磁屏蔽效能和优化多层磁屏蔽结构为目的,基于磁路理论,设计制备了铁基梯度复合结构材料,实现磁场和电磁场的综合屏蔽。同时,研究了层状组织演变对屏蔽性能的影响和屏蔽机理,优化制备工艺和屏蔽性能。以磁路和磁阻理论模型为基础,推导出了单层和多层屏蔽体的磁屏蔽系数计算公式,据此设计了Fe-Ni和Fe-Al两种不同的梯度复合结构材料,并对二者的磁屏蔽系数进行表征,确定最佳的梯度结构。利用电镀和扩散热处理的方法制备了Fe-Ni梯度复合结构材料,具有Fe-Ni/Fe/Fe-Ni的“导磁/导磁/导磁”结构,Fe-Ni合金层中Ni元素含量由表及里逐渐减少,呈梯度分布;采用真空热压法制备了Fe-Al梯度复合结构材料,具有Fe/Fe-Al/Fe的“导磁/不导磁/导磁”结构,铝元素由中间向两侧基体扩散,其含量逐渐降低。研究了不同热扩散工艺下,Fe-Ni和Fe-Al梯度复合结构材料的微观组织演变过程。基于一维平板模型和薄膜扩散,对Fe-Ni互扩散后Ni元素的浓度分布方程进行理论推导,根据不同扩散温度和时间下Ni元素线扫描数据,拟合分析后得到了900℃、1000℃和1100℃的扩散系数分别为3.51?10-11 cm2/s,6.48?10-11 cm2/s和1.45?10-10 cm2/s。同时,可对Fe-Ni梯度复合结构材料中Ni元素分布进行预测,用于扩散工艺和屏蔽性能的优化。对不同扩散时间下,Fe-Al梯度复合结构材料的物相进行表征;取一半作为研究对象,通过Fe-Al反应扩散计算,确定了Fe-Al反应层的相演变过程为:Fe2Al5/Fe?Fe2Al5/Fe Al2/Fe?Fe2Al5/Fe Al2/?-Fe(Al)/Fe?Fe2Al5/Fe Al2/Fe Al/?-Fe(Al)/Fe?Fe Al2/Fe Al/?-Fe(Al)/Fe?Fe Al/?-Fe(Al)/Fe。对不同扩散工艺下的Fe-Ni梯度复合结构材料的屏蔽性能进行研究。研究表明,表层Ni含量在79%附近时,筒状的Fe-Ni梯度复合结构材料的磁屏蔽系数达到最大值,1000℃-6h和1100℃-3h时的峰值分别为27.3和28.9,相对于纯铁基体分别提高了7.7倍和8.2倍。建立了Fe-Ni梯度复合结构材料的扩散工艺、元素分布和磁屏蔽系数之间的定量关系,屏蔽系数计算结果与实验值相符。随着扩散温度升高,表层Ni含量越快降至79%,即磁屏蔽系数达到峰值的时间变短。Fe-Ni合金层中各成分梯度层与基体并联分流磁场,表层Ni含量在79%时的Fe-Ni合金层磁导率最大,分流衰减磁场能力最强,磁屏蔽性能最优,各层之间并无耦合作用。电镀镍后形成Ni/Fe/Ni结构的电磁屏蔽性能相对于基体提高了约20d B,其经过扩散热处理后,形成Fe-Ni梯度复合结构材料的电磁屏蔽性能再次提高,在30k Hz~1.5GHz频率范围内约为70~80d B。不同扩散温度和时间下的电磁屏蔽性能之间并未表现出明显的变化规律。与基体相比,Fe-Ni梯度复合结构材料电磁屏蔽性能的提高主要依靠额外增加的Fe-Ni合金层的吸收损耗A和其内部梯度多层结构的多重反射损耗B。研究了不同扩散时间下,Fe-Al梯度复合结构材料的屏蔽性能。与纯铁基体相比,平板状的Fe-Al梯度复合结构材料的磁屏蔽系数提高了1.6倍。随着扩散时间的延长(1h-6h),Fe-Al梯度复合结构材料的磁场屏蔽系数并无明显的变化,当扩散达到10h时,磁屏蔽效果有所增加。Fe-Al梯度复合结构材料是由两层软磁层和中间的Fe-Al不导磁层组成,内外导磁层对磁场进行两级分流衰减,且二者之间还存在耦合作用,从而获得较高的磁屏蔽效果。形成的Fe-Al软磁合金层,具有较高的磁导率,也有利于磁屏蔽性能的提高。Fe-Al梯度复合结构材料的电磁屏蔽效能高于纯铁基体,且随着扩散时间的增加,电磁屏蔽性能逐渐升高,达到到10h时,在30k Hz~1.5GHz频率范围内的电磁屏蔽效能可达80d B左右。Fe-Al梯度复合结构材料电磁屏蔽性能的提高,主要是由于Fe-Al反应层具有梯度多层结构,电磁波在材料中内部产生了额外的多重反射损耗B。在Fe/Al/Fe扩散偶表面电镀镍,经高温热压扩散后形成了Ni-Fe-Al梯度复合结构材料,具有Fe-Ni/Fe/Fe-Al/Fe/Fe-Ni结构。与平板状的Fe-Al梯度复合结构材料相比,900℃下扩散1h~6h形成的Ni-Fe-Al梯度材料磁屏蔽系数提高了25%~42%,表面的Fe-Ni合金层能够增加导磁层对磁场的分流衰减作用;Ni-Fe-Al梯度复合结构材料(900℃-1h)在30k Hz~1.5GHz频率范围内的的电磁屏蔽性能提高了约10~20d B,Fe-Ni合金层能够增加对电磁波的吸收损耗A。
[Abstract]:The electromagnetic environment of modern instruments and equipments is becoming more and more complex, and the requirements for shielding materials are more stringent. In order to improve the efficiency of magnetic shielding and optimize the multi-layer magnetic shielding structure, based on the magnetic circuit theory, the iron-based gradient composite structure material is designed and manufactured to realize the comprehensive shielding of magnetic field and electromagnetic field. The influence of microstructure evolution on the shielding performance and the shielding mechanism are discussed. The preparation process and shielding performance are optimized. Based on the theoretical model of magnetic circuit and magnetoresistance, the formulas for calculating the magnetic shielding coefficients of single-layer and multi-layer shielding materials are deduced. Fe-Ni gradient composite structure material was prepared by electroplating and diffusion heat treatment. It has the structure of "magnetic conduction/magnetic conduction/magnetic conduction" of Fe-Ni/Fe/Fe-Ni. The content of Ni in Fe-Ni alloy layer gradually decreases from the surface to the inside, showing gradient distribution. The microstructure evolution of Fe-Ni and Fe-Al gradient composites with Fe/Fe-Al/Fe structure is studied by means of one-dimensional plate model and thin film diffusion. The distribution equation is deduced theoretically. According to the data of line scan of Ni element at different diffusion temperature and time, the diffusion coefficients of 900 C, 1000 C and 1100 C are 3.51? 10-11 cm 2/s, 6.48? 10-11 cm 2/s and 1.45? 10-10 cm 2/s, respectively. Meanwhile, the distribution of Ni element in Fe-Ni gradient composite structure materials can be predicted and used for expansion. The phase evolution of Fe-Al reaction layer was determined by Fe-Al reaction-diffusion calculation. The phase evolution process of Fe-Al reaction layer was determined as follows: Fe2Al5/Fe?2Al5/Fe?Al2/Fe?2Al5/Fe(Al)/Fe?2Al5/Fe?Al/Fe(Al)/Al/?-Fe(Al)/F? E Al2/Fe Al/?-Fe(Al)/Fe?Fe Al/?-Fe(Al)/Fe.The shielding properties of Fe-Ni gradient composites with different diffusion processes were studied.The results show that the magnetic shielding coefficient of cylindrical Fe-Ni gradient composites reaches the maximum when the content of Ni in the surface layer is around 79%,and the peak values at 1000 ~6h and 1100 ~3h are 27.3 and 28.9 respectively. The diffusion process of Fe-Ni gradient composite materials was established, and the quantitative relationship between element distribution and magnetic shielding coefficient was established. The calculated results of shielding coefficient were in agreement with the experimental values. The Fe-Ni alloy layer with 79% Ni content has the highest permeability, the strongest shunt attenuation magnetic field ability, the best magnetic shielding performance and no coupling effect between the layers. The electromagnetic shielding performance of Ni/Fe/Ni structure formed after nickel plating is about 20 dB higher than that of the substrate. The electromagnetic shielding properties of Fe-Ni gradient composites are improved again after diffusion heat treatment. The electromagnetic shielding properties of Fe-Ni gradient composites are about 70-80dB in the frequency range of 30kHz-1.5GHz. There is no obvious change between the electromagnetic shielding properties of Fe-Ni gradient composites at different diffusion temperatures and time. The magnetic shielding properties of Fe-Al gradient composites with different diffusion time were studied. Compared with pure iron matrix, the magnetic shielding coefficient of the flat Fe-Al gradient composites increased by 1.6 times. The magnetic shielding coefficient of Fe-Al gradient composite material has no obvious change with the prolongation of dispersion time (1h-6h). When the diffusion reaches 10h, the magnetic shielding effect increases. The Fe-Al gradient composite material is composed of two layers of soft magnetic layer and Fe-Al non-conducting magnetic layer in the middle. The magnetic field is attenuated by two stages shunting between the inner and outer magnetic layer. The Fe-Al soft magnetic alloy layer has higher permeability and is beneficial to the improvement of magnetic shielding performance. The electromagnetic shielding effectiveness of Fe-Al gradient composite structure material is higher than that of pure iron matrix. With the increase of diffusion time, the electromagnetic shielding performance gradually increases to 10 h. The electromagnetic shielding effectiveness of Fe-Al gradient composite structure material can reach about 80dB in the frequency range of 30kHz~1.5GHz. The improvement of electromagnetic shielding performance of Fe-Al gradient composite structure material is mainly due to the gradient multi-layer structure of Fe-Al reaction layer, which causes additional multiple reflection loss B in the material. Nickel is plated on the surface of Fe/Al/Fe diffusion couple and hot-pressed at high temperature. Ni-Fe-Al gradient composites with Fe-Ni/Fe/Fe-Al/Fe/Fe/Ni structure were formed after diffusion, and the magnetic shielding coefficient of Ni-Fe-Al gradient composites was increased by 25%~42% compared with the flat Fe-Al gradient composites. The Fe-Ni alloy layer on the surface of Ni-Fe-Al gradient composites could increase the magnetic field attenuation by diversion. The electromagnetic shielding performance of Al-Al gradient composite structure material (900 1h) in the frequency range of 30kHz~1.5GHz is improved by about 10~20dB. Fe-Ni alloy layer can increase the absorption loss of electromagnetic wave A.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB33
本文编号：2186039
[Abstract]:The electromagnetic environment of modern instruments and equipments is becoming more and more complex, and the requirements for shielding materials are more stringent. In order to improve the efficiency of magnetic shielding and optimize the multi-layer magnetic shielding structure, based on the magnetic circuit theory, the iron-based gradient composite structure material is designed and manufactured to realize the comprehensive shielding of magnetic field and electromagnetic field. The influence of microstructure evolution on the shielding performance and the shielding mechanism are discussed. The preparation process and shielding performance are optimized. Based on the theoretical model of magnetic circuit and magnetoresistance, the formulas for calculating the magnetic shielding coefficients of single-layer and multi-layer shielding materials are deduced. Fe-Ni gradient composite structure material was prepared by electroplating and diffusion heat treatment. It has the structure of "magnetic conduction/magnetic conduction/magnetic conduction" of Fe-Ni/Fe/Fe-Ni. The content of Ni in Fe-Ni alloy layer gradually decreases from the surface to the inside, showing gradient distribution. The microstructure evolution of Fe-Ni and Fe-Al gradient composites with Fe/Fe-Al/Fe structure is studied by means of one-dimensional plate model and thin film diffusion. The distribution equation is deduced theoretically. According to the data of line scan of Ni element at different diffusion temperature and time, the diffusion coefficients of 900 C, 1000 C and 1100 C are 3.51? 10-11 cm 2/s, 6.48? 10-11 cm 2/s and 1.45? 10-10 cm 2/s, respectively. Meanwhile, the distribution of Ni element in Fe-Ni gradient composite structure materials can be predicted and used for expansion. The phase evolution of Fe-Al reaction layer was determined by Fe-Al reaction-diffusion calculation. The phase evolution process of Fe-Al reaction layer was determined as follows: Fe2Al5/Fe?2Al5/Fe?Al2/Fe?2Al5/Fe(Al)/Fe?2Al5/Fe?Al/Fe(Al)/Al/?-Fe(Al)/F? E Al2/Fe Al/?-Fe(Al)/Fe?Fe Al/?-Fe(Al)/Fe.The shielding properties of Fe-Ni gradient composites with different diffusion processes were studied.The results show that the magnetic shielding coefficient of cylindrical Fe-Ni gradient composites reaches the maximum when the content of Ni in the surface layer is around 79%,and the peak values at 1000 ~6h and 1100 ~3h are 27.3 and 28.9 respectively. The diffusion process of Fe-Ni gradient composite materials was established, and the quantitative relationship between element distribution and magnetic shielding coefficient was established. The calculated results of shielding coefficient were in agreement with the experimental values. The Fe-Ni alloy layer with 79% Ni content has the highest permeability, the strongest shunt attenuation magnetic field ability, the best magnetic shielding performance and no coupling effect between the layers. The electromagnetic shielding performance of Ni/Fe/Ni structure formed after nickel plating is about 20 dB higher than that of the substrate. The electromagnetic shielding properties of Fe-Ni gradient composites are improved again after diffusion heat treatment. The electromagnetic shielding properties of Fe-Ni gradient composites are about 70-80dB in the frequency range of 30kHz-1.5GHz. There is no obvious change between the electromagnetic shielding properties of Fe-Ni gradient composites at different diffusion temperatures and time. The magnetic shielding properties of Fe-Al gradient composites with different diffusion time were studied. Compared with pure iron matrix, the magnetic shielding coefficient of the flat Fe-Al gradient composites increased by 1.6 times. The magnetic shielding coefficient of Fe-Al gradient composite material has no obvious change with the prolongation of dispersion time (1h-6h). When the diffusion reaches 10h, the magnetic shielding effect increases. The Fe-Al gradient composite material is composed of two layers of soft magnetic layer and Fe-Al non-conducting magnetic layer in the middle. The magnetic field is attenuated by two stages shunting between the inner and outer magnetic layer. The Fe-Al soft magnetic alloy layer has higher permeability and is beneficial to the improvement of magnetic shielding performance. The electromagnetic shielding effectiveness of Fe-Al gradient composite structure material is higher than that of pure iron matrix. With the increase of diffusion time, the electromagnetic shielding performance gradually increases to 10 h. The electromagnetic shielding effectiveness of Fe-Al gradient composite structure material can reach about 80dB in the frequency range of 30kHz~1.5GHz. The improvement of electromagnetic shielding performance of Fe-Al gradient composite structure material is mainly due to the gradient multi-layer structure of Fe-Al reaction layer, which causes additional multiple reflection loss B in the material. Nickel is plated on the surface of Fe/Al/Fe diffusion couple and hot-pressed at high temperature. Ni-Fe-Al gradient composites with Fe-Ni/Fe/Fe-Al/Fe/Fe/Ni structure were formed after diffusion, and the magnetic shielding coefficient of Ni-Fe-Al gradient composites was increased by 25%~42% compared with the flat Fe-Al gradient composites. The Fe-Ni alloy layer on the surface of Ni-Fe-Al gradient composites could increase the magnetic field attenuation by diversion. The electromagnetic shielding performance of Al-Al gradient composite structure material (900 1h) in the frequency range of 30kHz~1.5GHz is improved by about 10~20dB. Fe-Ni alloy layer can increase the absorption loss of electromagnetic wave A.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB33
【参考文献】
相关期刊论文 前1条
1 Xian-Hua Chen;Li-Zi Liu;Juan Liu;Fu-Sheng Pan;;Enhanced Electromagnetic Interference Shielding of Mg Zn Zr Alloy by Ce Addition[J];Acta Metallurgica Sinica(English Letters);2015年04期
，本文编号：2186039
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