鐵基磁屏蔽梯度復合結(jié)構材料制備與屏蔽性能研究
發(fā)布時間：2018-08-16 12:52
【摘要】：現(xiàn)代儀器和設備所處的電磁環(huán)境日趨復雜,對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優(yōu)化多層磁屏蔽結(jié)構為目的,基于磁路理論,設計制備了鐵基梯度復合結(jié)構材料,實現(xiàn)磁場和電磁場的綜合屏蔽。同時,研究了層狀組織演變對屏蔽性能的影響和屏蔽機理,優(yōu)化制備工藝和屏蔽性能。以磁路和磁阻理論模型為基礎,推導出了單層和多層屏蔽體的磁屏蔽系數(shù)計算公式,據(jù)此設計了Fe-Ni和Fe-Al兩種不同的梯度復合結(jié)構材料,并對二者的磁屏蔽系數(shù)進行表征,確定最佳的梯度結(jié)構。利用電鍍和擴散熱處理的方法制備了Fe-Ni梯度復合結(jié)構材料,具有Fe-Ni/Fe/Fe-Ni的“導磁/導磁/導磁”結(jié)構,Fe-Ni合金層中Ni元素含量由表及里逐漸減少,呈梯度分布;采用真空熱壓法制備了Fe-Al梯度復合結(jié)構材料,具有Fe/Fe-Al/Fe的“導磁/不導磁/導磁”結(jié)構,鋁元素由中間向兩側(cè)基體擴散,其含量逐漸降低。研究了不同熱擴散工藝下,Fe-Ni和Fe-Al梯度復合結(jié)構材料的微觀組織演變過程�；谝痪S平板模型和薄膜擴散,對Fe-Ni互擴散后Ni元素的濃度分布方程進行理論推導,根據(jù)不同擴散溫度和時間下Ni元素線掃描數(shù)據(jù),擬合分析后得到了900℃、1000℃和1100℃的擴散系數(shù)分別為3.51?10-11 cm2/s,6.48?10-11 cm2/s和1.45?10-10 cm2/s。同時,可對Fe-Ni梯度復合結(jié)構材料中Ni元素分布進行預測,用于擴散工藝和屏蔽性能的優(yōu)化。對不同擴散時間下,Fe-Al梯度復合結(jié)構材料的物相進行表征;取一半作為研究對象,通過Fe-Al反應擴散計算,確定了Fe-Al反應層的相演變過程為: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。對不同擴散工藝下的Fe-Ni梯度復合結(jié)構材料的屏蔽性能進行研究。研究表明,表層Ni含量在79%附近時,筒狀的Fe-Ni梯度復合結(jié)構材料的磁屏蔽系數(shù)達到最大值,1000℃-6h和1100℃-3h時的峰值分別為27.3和28.9,相對于純鐵基體分別提高了7.7倍和8.2倍。建立了Fe-Ni梯度復合結(jié)構材料的擴散工藝、元素分布和磁屏蔽系數(shù)之間的定量關系,屏蔽系數(shù)計算結(jié)果與實驗值相符。隨著擴散溫度升高,表層Ni含量越快降至79%,即磁屏蔽系數(shù)達到峰值的時間變短。Fe-Ni合金層中各成分梯度層與基體并聯(lián)分流磁場,表層Ni含量在79%時的Fe-Ni合金層磁導率最大,分流衰減磁場能力最強,磁屏蔽性能最優(yōu),各層之間并無耦合作用。電鍍鎳后形成Ni/Fe/Ni結(jié)構的電磁屏蔽性能相對于基體提高了約20d B,其經(jīng)過擴散熱處理后,形成Fe-Ni梯度復合結(jié)構材料的電磁屏蔽性能再次提高,在30k Hz~1.5GHz頻率范圍內(nèi)約為70~80d B。不同擴散溫度和時間下的電磁屏蔽性能之間并未表現(xiàn)出明顯的變化規(guī)律。與基體相比,Fe-Ni梯度復合結(jié)構材料電磁屏蔽性能的提高主要依靠額外增加的Fe-Ni合金層的吸收損耗A和其內(nèi)部梯度多層結(jié)構的多重反射損耗B。研究了不同擴散時間下,Fe-Al梯度復合結(jié)構材料的屏蔽性能。與純鐵基體相比,平板狀的Fe-Al梯度復合結(jié)構材料的磁屏蔽系數(shù)提高了1.6倍。隨著擴散時間的延長(1h-6h),Fe-Al梯度復合結(jié)構材料的磁場屏蔽系數(shù)并無明顯的變化,當擴散達到10h時,磁屏蔽效果有所增加。Fe-Al梯度復合結(jié)構材料是由兩層軟磁層和中間的Fe-Al不導磁層組成,內(nèi)外導磁層對磁場進行兩級分流衰減,且二者之間還存在耦合作用,從而獲得較高的磁屏蔽效果。形成的Fe-Al軟磁合金層,具有較高的磁導率,也有利于磁屏蔽性能的提高。Fe-Al梯度復合結(jié)構材料的電磁屏蔽效能高于純鐵基體,且隨著擴散時間的增加,電磁屏蔽性能逐漸升高,達到到10h時,在30k Hz~1.5GHz頻率范圍內(nèi)的電磁屏蔽效能可達80d B左右。Fe-Al梯度復合結(jié)構材料電磁屏蔽性能的提高,主要是由于Fe-Al反應層具有梯度多層結(jié)構,電磁波在材料中內(nèi)部產(chǎn)生了額外的多重反射損耗B。在Fe/Al/Fe擴散偶表面電鍍鎳,經(jīng)高溫熱壓擴散后形成了Ni-Fe-Al梯度復合結(jié)構材料,具有Fe-Ni/Fe/Fe-Al/Fe/Fe-Ni結(jié)構。與平板狀的Fe-Al梯度復合結(jié)構材料相比,900℃下擴散1h~6h形成的Ni-Fe-Al梯度材料磁屏蔽系數(shù)提高了25%~42%,表面的Fe-Ni合金層能夠增加導磁層對磁場的分流衰減作用;Ni-Fe-Al梯度復合結(jié)構材料(900℃-1h)在30k Hz~1.5GHz頻率范圍內(nèi)的的電磁屏蔽性能提高了約10~20d B,Fe-Ni合金層能夠增加對電磁波的吸收損耗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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TB33
本文編號：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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TB33
【參考文獻】
相關期刊論文 前1條
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
，本文編號：2186039
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