新型吸波合金Ce3YFe88B7的制备及性能研究

采用真空熔炼、球磨和退火处理的方法制得一种新型的吸波材料Ce3YFe88B7,测试发现Ce3YFe88B7在8.2 GHz~12.5 GHz频率范围内对微波吸收量整体较高波动较小,且随着球磨时间的增加而提高。经退火处理后Ce3Fe88B7样品的微波吸收量会大幅度提升。其中球磨40 h未退火处理的样品在频率在10.88 GHz处达到最大值47.251 dB,该样品在550℃温度下退火15 min处理后吸波性显著提高,在频率为12.02 GHz处吸收量达到最大值113.670 dB。     

富含稀土白云选铁尾矿制备的微波吸收材料特性研究

以白云鄂博选铁尾矿为原料制备吸波材料,在7.6～11.5GHz对其吸收特性进行分析研究,实验结果表明,在富含铁及多种稀土元素的选铁尾矿中加入2%的磁性及电性介质,经过650℃热处理后,最大吸收量达21dB,13dB带宽2.4GHz。该尾矿用于制备吸波材料,具有较大的研究意义。     

化学共沉淀法制备的BaNiZnCexFe16-xO27超微粉末的微波吸收特性

采用化学共沉淀法制备了BaNiZnCexFe16-xO27铁氧体吸波材料,就铈元素的含量对钡镍锌铁氧体吸波性能的影响进行了对比研究.实验发现在涂层厚度为1mm,测试频段为8.2GHz～12.5GHz频率范围内,当x=0.03时,该铁氧体材料的微波吸收特性最佳,在11.6GHz处,最大吸收值达13.6dB,10 dB以上带宽大于1.4GHz,其复介电常数ε″最大值为1.3,复磁导率μ″最大值为0.78,添加铈是提高钡镍锌铁氧体吸波材料性能的一种有效途径.     

退火处理对FeCo纳米粒子吸波性能的影响

用KBH4作为还原剂,采用化学还原法制备FeCo纳米粒子,然后在400~600℃下退火。利用X射线衍射仪、扫描电镜、X射线光电子能谱仪和振动样品磁强计对FeCo纳米粒子进行表征,用网络矢量分析仪测定其电磁参数,并分析FeCo的吸波性能,研究退火温度对FeCo纳米粒子吸波性能的影响。结果表明,化学还原法制备的FeCo纳米粒子,在厚度为5 mm时对频率为2.24 GHz电磁波的反射损耗最大,为-14.9 dB,损耗机制以介电损耗为主。随退火温度从400℃升高到600℃,FeCo纳米粒子的介电损耗逐渐减小而磁损耗逐渐增大,在400℃退火后的FeCo粒子具有最优的电磁匹配特性和最高的反射损耗,在厚度为3.55 mm时对4.48 GHz电磁波的反射损耗为-49.14 dB。     

共沉淀法制备的BaNiZn0.5Co0.5Cex Fe16-x O27纳米铁氧体微波吸收特性研究

采用共沉淀法制备了BaNiZn0.5 Co0.5 Cex Fe16-x O27(x=0,0.01,0.03,0.05)纳米铁氧体粉末,就铈元素的含量对该铁氧体微波性能的影响进行了对比研究,用AV3618型微波矢量网络分析仪测试了样品在8.2GHz～12.5GHz范围内的微波吸收特性.实验发现,稀土元素铈的含量影响材料的吸波性能,当x=0.03时,BaNiZn0.5Co0.5CexFe16-xO27铁氧体的吸波性能最佳.对于BaNiZn0.5Co0.5Ce0.03Fe15.97O27铁氧体吸波材料,当涂层厚度为1mm时,在11.8GHz频率处,最大吸收衰减量达14.8dB,9dB以上带宽大于2GHz,其复介电常数ε"最大值为1.83,复磁导率μ"最大值为0.95,添加铈是提高该铁氧体吸波材料性能的一种途径.     

化学共沉淀法制备的Ba0.5Sr0.5Co0.8Fe0.2-xCexO3微波吸收特性研究

采用化学共沉淀法制备了Ba0.5Sr0.5Co0.8Fe0.2-xCexO3(x=0,0.01,0.025,0.05)复合氧化物,用.XRD分析了材料的相结构,并用AV3618型微波矢量网络分析仪测试了样品在8.2GHz～12.5GHz范围内的微波吸收特性,结果表明,在1100℃煅烧后样品呈现出单一的钙钛矿型结构,铈的含量影响材料的吸波性能,当x=0.025时,Ba0.5Sr0.5Co0.8Fe0.2-xCexO3的吸波性能最佳,材料涂层厚度为1mm时,在测试频段内有三个吸收峰,最高的吸收峰位于9.06GHz处,吸收峰值达36.83dB,18dB以上频带宽度达2.2GHz,适量掺杂铈是提高该复合氧化物吸波性能的一种有效途径.     

溶胶-凝胶法制备的LaxSr1-xMnO3纳米粉末微波吸收特性研究

采用溶胶-凝胶法制备了稀土锰氧化物LaxSr1-xMnO3(x =0.5,0.7,0.9)纳米粉末,用XRD分析了该材料的相结构,并用AV3618型微波矢量网络分析仪测试了样品在8.2GHz～12.5GHz范围内的微波吸收特性.结果表明,在1000℃焙烧后样品出现单一的钙钛矿型结构,当材料涂层厚度为1mm、x=0.7时,La0.7Sr0.3MnO3的吸波性能最佳.在测试频段内有五个明显的吸收峰,最高吸收峰在11.2GHz处,其吸收峰值达34dB,20 dB以上频带宽度达3GHz,是一种有发展前景的微波吸收材料.     

MgFe_2O_4铁氧体改性羰基铁粒子制备及吸波性能

采用非均匀成核和化学沉淀相结合的方法制备了MgFe2O4铁氧体改性羰基铁(Carbonyl Iron,CI)复合粒子。用XRD和SEM对产物的晶体结构和微观形貌进行分析;研究了改性前后粒子在2~18GHz的电磁参数和吸波性能。结果表明:采用非均匀成核和化学沉淀相结合的方法可以制备MgFe2O4包覆CI复合粒子;改性粒子的复磁导率和介电常数实部较CI降低;介电常数虚部在频率为6~11.5GHz时大于CI,并在9 GHz左右有一个电损耗谱峰;改性粒子在-10 dB处频宽大于CI,最大吸收峰位置较CI向高频迁移;吸收层厚度为1.5 mm时,改性粒子的吸收峰值为-17.8241 dB,-10 dB的频宽为5.52 GHz,较改性前CI粒子,有效地改善了单一CI作为吸波剂的吸波性能。     

溶胶-凝胶法制备的(La1-xCex)2/3Sr1/3MnO3超微粉末微波吸收特性研究

采用溶胶-凝胶法制备了钙钛矿型锰氧化物(La1-x Cex)2/3Sr1/3 MnO3(x=0.1,0.3,0.5)超微粉末,用XRD分析了该材料的相结构,并用AV3618型微波矢量网络分析仪测试了样品在8.2GHz～12.5GHz范围内的微波吸收特性.结果表明,样品在1000℃焙烧后出现单一的钙钛矿型结构,当材料涂层厚度为1mm、x=0.3时,(La1-x Cex)2/3 Sr1/3 MnO3的吸波性能最佳.在测试频段内有三个吸收峰,最高的吸收峰在9.1GHz处,峰值高达36.8dB,并且吸收衰减量大于18dB的频带宽度达2.2GHz.     

Cr含量对NdFeB材料微波吸收特性的影响

采用高能球磨和在微氧化气氛晶化热处理的方法制备钕铁硼吸波粉体,借助X射线衍射仪和微波矢量网络分析仪测量系统分析,研究Cr含量对钕铁硼粉体组织结构和微波吸收特性的影响.结果发现:高能球磨和微氧化气氛下进行600℃×2 h晶化处理后Nd11.76 Fes2.35 B5.88粉体组织由α-Fe,Nd2O3,Fe23(B.C)6相组成,加入Cr不改变NdFeB粉体的相组成,但可使粉体中的Fe23 (B.C)6相对量减少,而α-Fe相对量增加;加入Cr可降低NdFeB粉体的复介电常数实部ε’和虚部ε"以及复磁导率实部μ’,尤其是Nd26.67Fe69.83 Cr2.5B粉体的复介电常数虚部ε"降低得最多,加入Cr使NdFeB粉体的复磁导率虚部μ"在4- 10 GHz频段时增大,而大于10 GHz频率后,复磁导率虚部μ"变化不大;吸波涂层厚度为1.5mm时,Nd11.76Fe82.35B5.85粉体的反射率最小值约为-8.5 dB,吸收峰频率约为10 GHz;Nd26.67 Fe69.83Cr2.5B反射率最小值降低到- 17.0 dB,吸收峰频率升高到15.5 GHz,当将Cr含量增加到4％时,粉体的反射率最小值回升到-10.8dB,吸收峰频率升高到15.8GHz;加入Cr会使NdFeB粉体的吸波带宽变窄.     

Recent Trends in China's Copper Scrap Market-Part Ⅱ

<正>2.Tianjin Scrap Metal Market In Tianjin,we mainly visited Jinghai Ziy Town scrap market and Binhai New Area’some copper scrap enterprises and enterprise using copper scrap.In Ziya we felt the coppe scrap market was particularly deserted,mos copper scrap enterprises in the town wer closed,industry insiders said in 2012 the plac here was bustling with activity.According to     

Acceleration of Electricity Reform Brings Benefit to Big Electricity Users,Aluminum Manufacturers Can Save Costs Up to Several Hundred Million

<正>Recently the National Commission of Development and Reform again assembled experts to solicit opinions,and discussed new electricity reform program.According to information disclosed by experts attending the meeting,in the future electricity reform will undergo top-down design,possibly a     

Qinghai's Aluminum Processing Capacity to Rise at the End of the Year

正Since the release of Implementation Opinions on Carrying out‘Guiding Opinions of the State Council on Resolving Serious Production Overcapacity Conflicts’,according to the actual situation of industry,Qinghai has focused on electrolytic aluminum,cement,ironsteel(including iron alloy and silicon carbide),     

China’s Mineral Exploration Market Downturn Causes Decline of Investment in Bauxite

<正>According to a survey report conducted recently by China Geological Survey Development Research Center,in the first half of 2014,China’s mineral exploration market continued to decline,with the investment in exploration of non-fuel minerals dropping by13.7%and drilling workload dropping by21.7%.According to statistical analysis of the Center,     

Shanghai Clearing House to Roll out Renminbi-denominated Copper Clearing Operations in Free Trade Zone

正Clearing House Financial Markets Co.,Ltd.(Shanghai Clearing House)General Manager Xie Zhong told the media recently at the briefing of the international symposium of"Reform Deepening and Mechanism Innovation of the Post-crisis Kerb Market",Shanghai Clearing House will explore the feasibility of carrying out bond business in     

Development and Application of New Materials for Copper Processing in China

正After over 60 years of developmnt,a system for RD and production of copper processing materials has already taken shape in China.After the reform and opening-up,the application of copper processing materials has gradually expanded from the military industry to civil field.The annual output of copper     

Aluminium Production by Province or City in 2014

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Fabricated Copper Production by Province or City in 2014

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Zinc Production by Province in 2014

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China's Aluminum Alloy Cable Market has Taken Shape

正Aluminum alloy cable is a mature product and technology that has been used for nearly fifty years in the U.S.Through six years’promotion,it has been widely recognized and accepted in the China market since 2013,which laid the foundation for the development of the aluminum alloy cable market.Aluminum alloy cable is widely applied in the fields of civil construction and industrial and mining enterprises,especially in real estate,steel and metallurgy.