FeSiAl电磁屏蔽涂层的腐蚀行为对吸波性能的影响

以在Q235冷轧钢板表面涂敷的FeSiAl电磁屏蔽涂层为研究对象,通过改变固化条件,探究了电磁屏蔽涂层的最优固化环境.同时,运用中性盐雾试验、电磁屏蔽性能测试和电化学阻抗试验,研究了自然条件固化后涂层的吸波性能和耐蚀性能随盐雾周期不同的变化规律.结果表明,电磁场下固化会损害涂层的腐蚀屏蔽性.吸波剂含量的增加不利于提升涂层的吸波性能,同时也会损害涂层的腐蚀屏蔽性.长期盐雾试验后,涂层的吸波性能随腐蚀屏蔽性的降低而下降.      

稀土La掺杂对层状富锂锰基氧化物正极材料结构及电化学性能的影响

采用碳酸盐共沉淀-高温烧结法制备了La掺杂层状富锂锰基氧化物正极材料Li_1.2Mn_0.54-xNi_0.13Co_0.13La_xO₂（x=0, 0.01, 0.03, 0.05），考察了La掺杂量对正极材料的结构及电化学性能的影响.采用X射线衍射（XRD）和扫描电镜（SEM）分析研究了正极材料的结构和形貌特征，材料的电化学性能采用交流阻抗和充放电测试仪进行测试分析.研究结果表明:所有样品均保持层状α-NaFeO₂结构，随着La掺杂量的增加，样品形貌未发生明显变化，样品放电容量呈现先增大后降低的趋势，当La掺杂量为0.03时，具有最高的放电比容量285.3 mAh/g（0.1 C），经过50次循环后的放电比容量为260.5 mAh/g，容量保持率为91.3 %.      

等离子喷涂CeO2改性La2Zr2O7纳米热障涂层高温性能研究

研究了不同Ce掺杂量对La2Zr2O7相结构稳定性的影响,确定了Ce原子掺杂量为5.45％的CeO2改性La2Zr2O7涂层（CLZ）.研究了采用大气等离子喷涂制备的涂层与原始粉末化学成分计量比偏离情况.经共沉淀制粉、喷雾干燥团聚造粒、大气等离子喷涂制备了Ce原子掺杂量为5.45％的新型纳米CLZ热障涂层,研究了涂层的长期组织结构稳定性、抗热震性以及失效机制.结果表明,CLZ涂层具有良好的长期组织结构稳定性,涂层在1150℃下热震循环寿命达到26次.涂层失效主要以层状撕裂为主.陶瓷层和粘结层热膨胀不匹配、粘结层发生氧化可能是导致CLZ涂层热震失效的主要原因.     

等离子喷涂Fe-Co基非晶合金涂层的结构与电磁屏蔽性能

采用气雾化制备了Fe_(36)Co_(36)B_(20)Nb_4Si_4合金粉末,利用大气等离子喷涂在H62铜板和铝管表面制备了厚度约为0.2~0.3 mm的非晶合金涂层。结果表明:Fe_(36)Co_(36)B_(20)Nb_4Si_4合金涂层几乎为完全的非晶态结构,涂层硬度高达1 200 HV,喷涂有Fe_(36)Co_(36)B_(20)Nb_4Si_4涂层的样品对直流磁场和高频电磁场均具有良好的屏蔽性能,在800 A/m直流磁场下屏蔽效能为25 dB,在300 kHz~1.5 GHz频段屏蔽效能约为80 dB。     

高温固相法制备Sm2O3掺杂La2Ce2O7热障涂层材料

以La2O3、Ce O2和Sm2O3为原料,采用高温固相反应法制备了Sm2O3部分掺杂La2Ce2O7热障涂层陶瓷材料,其化学式为(SmxLa1-x)2Ce2O7.采用X射线衍射法研究了试样的物相结构,并通过对比各实验条件下制备的试样的X射线衍射图谱,对试样的掺杂比例、烧制温度及烧制时间进行了探究.结果表明,所制备试样为萤石结构,当掺杂摩尔比Sm∶La为1∶2或1∶3时试样均能保持良好的相结构,以掺杂摩尔比Sm∶La=1∶2制备的(Sm0.33La0.67)2Ce2O7材料在1600℃下具有良好的相稳定性,且其最佳制备条件为1550℃下烧制10 h,该材料是一种很有潜力的新型热障涂层陶瓷材料.     

Ca2+、La3+掺杂纳米Y2O3∶Eu3+的超声波制备及光致发光性能

采用超声波作用下的均匀沉淀法制备Ca2 、La3 掺杂的纳米Y2O3∶Eu3 荧光粉.通过正交实验研究掺杂浓度、溶液pH、超声功率、反应时间、干燥温度、煅烧温度等因素对其光致发光(PL)性能的影响,得到制备Ca2 、La3 掺杂纳米Y2O3∶Eu3 的最佳条件.结果表明,超声功率、Eu(NO3)3浓度、尿素体积、氨水浓度、煅烧温度是影响样品PL强度的主要因素.Ca2 、La3 离子单一掺杂效果优于两种元素的复合掺杂,最佳条件下制备的Ca2 、La3 分别掺杂的纳米Y2O3∶Eu3 荧光粉的发光性能均显著优于未掺杂样品.     

低量La3+掺杂WO3的表征及其光解水催化性能的研究

采用低热固相反应法制备了低量La3+(0.05%)掺杂的WO3催化材料,采用XRD、XPS和DRS对样品进行了表征和分析,考察了样品光催化分解水制氧的活性。结果表明,0.05%La3+掺杂可使WO3光谱响应范围向可见光区拓展。XPS分析表明,La3+掺杂可导致粉体表面晶格氧的增加。在可见光辐射下光催化分解水制氧的试验中,0.05%La3+掺杂WO3的光催化析氧速率高达177μmol/(L.h),是未掺杂WO3的1.8倍。     

CeO2对Ti基RuO2-SnO2涂层阳极电催化性能的影响

采用热分解法制备了掺杂CeO2的Ti基RuO2-SnO2涂层阳极,通过开路电位测试、循环伏安测试以及交流阻抗测试研究了所制备涂层阳极的电催化性能,并用扫描电镜观察了涂层阳极的表面形貌。结果表明,在涂层阳极中掺杂CeO2可以提高涂层阳极的电催化活性,CeO2的最佳掺杂量为0.4(摩尔分数)。涂层阳极电催化性能提高的原因在于掺杂的CeO2可以提高涂层的有效活性表面积。     

La0.7Sr0.3Mn1-xRxO3(R=Co,Ni)的共沉淀法合成及磁性研究

用液相共沉淀法合成了La0.7Sr0.3Mn1-xRxO3(R=Co,Ni)样品.利用XRD对样品结构进行表征,结果表明,由于Co2 半径与Mn3 离子半径不匹配,当Co2 含量x>0.07时,样品La0.7Sr0.3Mn1-xRxO3的结构由正交晶系向单斜晶系转变,而Ni2 离子半径与Mn3 离子半径相近,Ni的掺杂并没有改变系列样品La0.7Sr0.3Mn1-xRxO3的晶体结构.通过振动样品磁强计测试样品的磁性,结果表明,La0.7Sr0.3Mn1-xRxO3(R=Co,Ni)系列样品的比饱和磁化强度随掺杂浓度的增加而减少,这是由于Co2 和Ni2 取代Mn3 后,引起B位离子的电场差的减少.样品的稳定性降低,而使得比饱和磁化强度降低.     

La掺杂TiO_2薄膜的制备与光生阴极保护研究

采用溶胶凝胶法利用浸渍提拉技术在430不锈钢基片上制备了纯TiO_2与La掺杂TiO_2薄膜。利用XRD、SEM、EDS、XPS等测试技术对样品进行晶型结构、表面形貌和元素组成的表征分析;采用Tafel曲线对薄膜耐腐蚀性能进行测试。结果表明,La掺杂没有改变TiO_2晶型结构,二者均为锐钛矿,La掺杂有细化晶粒的作用;La掺杂TiO_2薄膜更加均匀致密;光照时,薄膜都有一定的光生阴极保护作用,La掺杂TiO_2薄膜的光生阴极保护作用优于纯TiO_2薄膜。     

Study on Electromagnetic Shielding Effectiveness of Ni-P-La Alloy Coatings

Ni-P and Ni-P-La alloy coatings were prepared by electroplating. Electromagnetic shielding effectiveness under the different components of rare earth or the different operating conditions was tested by the network analyzer. The results show that electromagnetic shielding effectiveness of Ni-P-La alloy coating varies from 45 dB to 70 dB with the variety of the frequency from 10 MHz to 350 MHz. Corrosion of the salt fog impacts on the electromagnetic shielding effectiveness a little. A small amount of rare earth added to plating bath can not only enhance corrosion resistance of coating, but make electromagnetic shielding effectiveness increase by 1～5 dB.     

水溶性电磁屏蔽涂料的研究现状

电磁屏蔽涂料是应用广泛的防电磁辐射材料。本文介绍了水溶性树脂的合成原理，分析了国内电磁屏蔽涂料的研究状况，展望了电磁屏蔽涂料的应用前景。     

电磁搅拌下稀土在铝合金熔体中的分布规律

应用Ansys软件中电磁场模拟模块Ansoft以及流场模块Fluent,研究在单一低频旋转电磁场作用下A356-1.2 %La熔体中稀土La的运动规律以及分布规律. 通过对单一低频且搅拌时间短暂电磁搅拌情况下的A356-1.2 %La熔体进行建模仿真,并着重对电磁搅拌频率分别为f=5 Hz、15 Hz、30 Hz时稀土La的分布情况进行对比分析,最终得出当电磁搅拌频率f=30 Hz时熔体内稀土La分布相对均匀;且一定条件下随着电磁搅拌时间以及频率的增加,稀土La在A356-1.2 %La熔体内的分布也越均匀;并证实通过Ansys软件中电磁场模块Ansoft以及流场模块Fluent可以较好地对旋转电磁场内铝-稀土多相熔体中稀土的运动情况进行数值仿真.      

惰性气体保护5 t电渣炉重熔铁路用G20CrNi2MoA渗碳轴承钢

试验和分析了全封闭气罩氩气保护电渣重熔与常规大气下电渣重熔铁路用G20CrNi2MoA渗碳轴承钢(/%:0.19C、0.49Cr、1.75Ni、0.23Mo、0.071Al)的冶金效果。结果表明,氩气保护电渣重熔锭Si和Mn的烧损量(3%～12%和4%～10%)低于常规电渣重熔锭Si和Mn的烧损量(15%～18%和7%～10%);当G20CrNi2MoA钢电极的氧含量为10×10^-6时,氩气保护电渣锭的氧含量(15×10^-6)低于常规电渣锭的氧含量(21.3×10^-6);氩气保护电渣锭的冶金质量明显优于未经气体保护的常规电渣锭。     

电缆屏蔽层接地方式及PLC信号抗干扰分析

电缆屏蔽层接地是抑制干扰信号的重要手段,是维持系统稳定运行的重要措施。其抑制干扰的能力除与屏蔽层本身质量有关外,还与屏蔽层接地方法密切相关。良好的屏蔽需选择正确的屏蔽层接地方式、接地点数及接地位置。     

双辊薄带连铸熔池密闭方法及结构分析

双辊薄带连铸生产薄带钢技术具有节能环保、工艺流程短等优点.对已公开的薄带连铸熔池密闭室工作方法及结构形式进行了分析,并按照功能和结构将熔池密闭室分为:可分段控制铸辊冷却强度的熔池密闭室装置、多气体腔室的熔池密闭室装置、采用混合气体影响熔池传热的熔池密闭装置以及能主动去除熔池表面浮渣的熔池密闭室装置等,最后总结了一套密闭室的设计思路.     

Research on electromagnetic properties of electromagnetic stirring roller

Using computer simulation and test measurements,the relationship between the electromagnetic properties of an electromagnetic stirring roller and the roller structure parameters was analyzed and compared. The distribution of the magnetic field,magnitude of the electromagnetic force,and matched-load characteristics were systematically investigated at different parameter values for the induction coils,iron core,shield,and roller sleeve.The results indicate that the change in the electromagnetic force with stirring frequency is non-linear and has a maximum value higher than 10 Hz; the electromagnetic force largely depends on the diameter of the core; and there is a mutual restriction relationship between the two-phase imbalance and the electromagnetic force.     

Effect of Ball Scribing on Magnetic Shielding Efficiency of Grain-oriented Silicon Steel

Magnetic shielding of grain-oriented silicon steel was investigated. Ball scribing with spacing of 2 to 16 mm was performed at peak flux densities of 8.0 mT to 1.3 T. Magnetic shielding efficiency was calculated, including absorption, reflection and inner multi-reflection shielding efficiencies. Magnetic shielding efficiency （MSE） increase ratios after different scribing spacing were compared, and thickness requirement to achieve absorption shielding of 50 dB was also calculated. The results show that magnetic shielding efficiencies of C711 and H668 silicon steels increase by 4.79 and 3.15 dB respectively after scribing of 16 mm. Before scribing, shielding efficiency of H668 steel was higher than that of C711 steel, while after scribing, both absorption and shielding efficiency gaps were largely abridged between C711 and H668 steels. Plate thickness of C711 steel could be reduced from 3.18 mm without scribing to 2. 20 mm after scribing of 16 mm. There is no apparent thickness reduction at lower flux densities; while the peak flux density is above 0.3 T, the shielding effect becomes apparent, and the thickness could be reduced from 2.28 mm without scribing to 1.70 mm with scribing spacing of 16 ram. Magnetizing process and its effect on variation of magnetic shielding were also analyzed.     

Transverse Thermal Behavior of a Hot-Rolled Strip During the Edge-Induction-Heating Process

To obtain the transverse temperature distribution of running strips under C-type edge induction heaters during the hot-rolling process, a coupled electromagnetic–thermal finite-element model is established using COMSOL, in which the electromagnetic and temperature distributions regularity with various process parameters are systematically obtained. It is shown in the results that the temperature increase is directly proportional to the frequency and current and inversely proportional to the thickness. Meanwhile, the edge temperature drop can be rapidly compensated for using an edge heater, but it also leads to the appearance of a “cat-ear” high-temperature zone at the edge; thus, the transverse temperature uniformity cannot be guaranteed. To improve the temperature uniformity of the running strip, a magnetic shield plate is designed to weaken the effect of the cat ear, and the effects of the size and installation position of the shielding plate on the temperature distribution are analyzed. The standard deviation and uniformity of the temperature are used to determine the uniformity of the transverse temperature, and the optimal parameter combination mode of the magnetic shielding amounts is obtained, which can provide a reference for optimizing the heating process at the edge of the strip under moving conditions.