黑镍太阳能选择性吸收涂层的研制

采用电镀方法在预镀银H85铜合金表面电化学沉积黑镍涂层,制备出了太阳能选择性吸收涂层。研究了电镀时间、电流密度以及光亮银底层等参数对涂层整体的太阳能吸收率α、发射率ε的影响,采用SEM、EDS、XRD以及光谱选择性(α/ε)等方法对涂层进行了表征,得到了制备黑镍太阳能选择性吸收涂层的优化工艺。实验结果表明,黑镍涂层主要相结构为N-Diamond C、NiO、NiC、NiZn3;添加光亮银红外反射层能较为明显地改善涂层的选择性吸收性能;获得了α=0.90,ε=0.06,α/ε=15的太阳能选择性吸收涂层。     

Nature of large （Ti, Nb）（C, N） particles precipitated during the solidification of Ti, Nb HSLA steel

To investigate the microsegregation phenomena and complex （Ti, Nb）（C, N） precipitation behavior during continuous casting, a unidirectional solidification unit was employed to simulate the solidification process. The samples of Ti, Nb-addition steels after unidirectional solidification were examined using field emission scanning electron microscope （FE-SEM） and electron probe X-ray microanalyzer （EPMA）. In such specimens, dendrite structure and mushy zone can be detected along the solidification direction. It shows that the addition of titanium, niobium to high-strength low-alloyed （HSLA） steel results in undesirable （Ti, Nb）（C, N） precipitation because of microsegregation. The effect of cooling rate on （Ti, Nb）（C, N） precipitation was investigated. The composition of large precipitates was determined using FE-SEM with EDS. Large （Ti, Nb）（C, N） precipitates could be divided into three kinds according to the composition and morphology. With the cooling rate increasing, Ti-rich （Ti, Nb）（C, N） precipitates are transformed to Nb-rich （Ti, Nb）（C, N） precipitates.     

Properties and Structure of Magnesium Matrix Composite Reinforced with CNTs

By using high pure Magnesium (99.9 wt% ) as matrix and multi-walled bended carbon nanotubes ( CNTs ) as reinforced phase, carbon nanotubes/magnesium matrix composite was prepared to the foundry method under the argon gas protection, and its mechanical properties were tested. The interface structure and component of plating and un-plating carbon nanotubes were analyzed by TEM and EDS , and the action mechanism was discussed. The experiment results show that the CNTs con strengthen mechanical properties of the nano-tube-reinforced Mg matrix composite, the tensile strength and elongation ratio are greatly improved. Furthermore, the plating CNTs are better than un-plating CNTs in strengthening effects. The tensile strength is inereased by 150% and the elongation ratio is increased by 30% than that of matrix when content of CNTs is 0.67 wt%.     

锦纶织物超声波纳米颗粒复合化学镀镍磷

分别使用十二烷基苯磺酸钠、十六烷基三甲基溴化铵和海藻酸钠分散纳米Al2O3、Si3N4和ZrC颗粒,并将其添加到化学镀镍液中;在超声波辅助条件下对锦纶织物进行纳米颗粒复合化学镀镍磷;借助SEM、EDX、XRD和TG测试技术对镀层表面形貌、成分、结构和织物热性能进行研究,并测试织物阻燃、耐磨和电磁波屏蔽性能.结果表明:与普通化学镀镍磷织物相比,不同纳米颗粒复合化学镀镍磷织物镀层表面形貌有所不同;结晶度增大,当纳米颗粒添加量不大时,晶粒尺寸有所减小;热起始分解温度降低(纳米Si3N4除外),耐高温分解温度升高,燃烧速度有所减慢,没有熔滴现象发生;电磁波屏蔽效能变化不大,随着增重率的增加,平均屏蔽效能逐渐增大,表面电阻减小;耐磨性能增强.     

Electromagnetic Interference Shielding Properties of Electroless Nickel-coated Carbon Fiber Paper Reinforced Epoxy Composites

Carbon fibers(CFs) were coated with a nickel-phosphorus(Ni-P) film using an electroless plating process. The morphology, elemental composition and phases in the coating layer of the CFs were investigated by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD), respectively. Wet paper-making method was used to prepare nickle coated carbon fiber paper(NCFP). Vacuum assisted infusion molding process(VAIMP) was employed to manufacture the NCFP reinforced epoxy composites, and carbon fiber paper(CFP) reinforced epoxy composites were also produced as a comparison. Electromagnetic interference(EMI) shielding properties of the composites were measured in the 3.22-4.9 GHz frequency range using waveguide method. Both NCFP and CFP reinforced epoxy composites of 0.5 mm thickness exhibited high EMI shielding effectiveness(SE) at 8wt% fiber content, 35 d B and 30 d B, respectively, and reflection was the dominant shielding mechanism.     

提高煤矿机件抗蚀耐磨性的盐浴复合处理工艺的研究

本文通过磨损实验、腐蚀实验以及小能量冲击剥落试验，证实了经盐浴复合处理的工件抗蚀耐磨性及抗冲击剥落能力均高于镀硬铬及镀锌磷化涂二硫化铂。同时，盐浴复合处理的总费用较低，在煤矿机件上具有广泛的应用前景。     

钡铁氧体表面化学镀Ni-P合金的制备及性能

为提高钡铁氧体的吸波性能,以钡铁氧体为芯材,采用化学镀的方法制备表面包覆Ni-P镀层的钡铁氧体复合粒子.并利用XRD、SEM、EDS及矢量网络分析仪对其晶体结构、表面形貌、成分、电磁吸收性能进行分析.结果表明:钡铁氧体表面包覆完整的Ni-P合金镀层,化学镀工艺显著改善材料的电磁性能,并提高材料对电磁波的吸收能力,镀后复合粒子在2～18GHz频段内,最大反射率为-24.3dB,大于-10dB的吸收频带宽约2.8GHz.     

基于GAMP的近场毫米波成像快速算法

传统近场毫米波均匀采样成像由于扫描时间长和计算代价大等问题无法实现实时成像。为此,该文构建了近场毫米波压缩采样成像模型及相应的观测矩阵,提出了一种基于广义近似消息传递的近场毫米波压缩采样成像快速算法。该算法将广义近似消息传递有效嵌入到期望最大化框架,加快了收敛速度;并利用快速傅里叶变换、小波滤波等方式构造了观测矩阵的快速算子,避免了大型观测矩阵的构造、存储与计算,进一步提升了算法运算速度。实验结果表明该算法可以快速、有效地从压缩采样数据中重建近场毫米波二维图像,并在重建效果与运算时间上都优于主流的快速迭代阈值收缩算法。     

Thermal Shock Resistances of FeMnCr/Cr_3C_2 Coatings Deposited by Arc Spraying

Arc spraying with the cored wires was applied to deposit FeMnCr/Cr3C2 coatings on low carbon steel substrates, namely FM1, FM2 and FM3. Thermal shock resistances of the coatings were investigated to assess the influence of Cr3C2 content on thermal shock resistance. Characteristics of the coatings under thermal cycling test were studied by optical microscopy, field emission scanning electron microscope (FE-SEM) and energy dispersion spectrum (EDS), X-ray diffraction (XRD). The experimental results show that ...     

非晶态镍磷合金空心微球的制备及其催化加氢性能

以空心玻璃微球作为模板材料,采用化学镀法在模板表面沉积了均匀的非晶态Ni-P合金镀层,用化学溶解法去除内部的空心玻璃微球模板,制备出非晶态Ni-P合金空心微球。分别利用EDS、SEM、XRD等手段对制品进行表征,以硝基苯液相加氢为探针反应,考察了非晶态Ni-P合金空心微球的催化加氢性能。结果表明,非晶态Ni-P合金空心微球具有良好的催化活性和循环使用性能。     

辐射计检测绝缘子污秽的天线温度模型

根据微波辐射特性,提出了基于污秽物在微波波段的辐射特性差异来检测绝缘子绝缘状况的方法,其原理是绝缘子上有污秽物时发射率会随污秽量和污秽性质变化导致辐射计天线温度的变化,并在三层媒质模型基础上建立了辐射计检测绝缘子污秽的天线模型,给出了天线温度与等值盐密和观察角之间的定量关系,并将数值计算结果与实际测量结果进行了比较,其结果基本一致。     

机载噪声耦合式增益自动补偿微波辐射计研究

通过2个耦合器将固态噪声源信号分别馈入到接收信号和射频开关端口，辐射计可在较大的范围内动态探测到被测目标小量微波辐射信号变化. 利用增益波动自动补偿技术，提高了设备的长期稳定性和灵敏度. 较好地解决了辐射计在环境温度剧烈变化下系统的稳定性问题，实现了机载条件下对云中过冷水的探测. 测试结果表明，仪器灵敏度范围在0.14~0.18K，主要技术指标能够满足测量要求. 与地面雷达和其它航空遥感仪器相比，它具有直接测量的局部区域准确性高，取样代表性好的特点.     

反应烧结制备Ti_2AlN-TiN复合材料

采用2Ti/2Al/3TiN粉体为原料,通过反应热压烧结,以制备Ti2AlN-TiN复合材料。采用X射线衍射（XRD）、场发射扫描电镜（FE-SEM）结合能谱仪（EDS）分析试样。研究结果表明,在1350℃保温2h,压力为30MPa,可烧结得到组织细小、致密的Ti2AlN-TiN复合材料。材料中层片状Ti2AlN晶粒长约5m,TiN晶粒大小为1~2m。复合材料具有良好的机械性能,其显微硬度与弯曲强度分别达8.57GPa和450MPa。     

氟塑料表面化学镀镍及镀层性能的研究

采用化学镀工艺在氟塑料表面成功获得了Ni-P镀层。通过扫描电镜(SEM)、X射线衍射仪(XRD)、能谱分析仪(EDS)和电化学工作站对镍镀层的形貌、生长方式、组成、结构、耐腐蚀性和电化学阻抗进行分析表征。实验结果表明,镀层均匀、致密、性能良好。镀层明显改善了氟塑料膜的导电性。在200～250℃下进行热处理有利于提高镀层晶化程度,改善镀层导电性。通过静态腐蚀试验和电化学测试表明镀层耐腐蚀性良好。     

Synthesis of M(M=Co~(2+),Co~(2+)/Ni~(2+))-doped FeS_2 Nanospheres with Enhanced Visible-light-induced Photocatalytic Activity

Nano-spherical Co~(2+)-doped FeS_2 was synthesized through a simple solvothermal method. The products were investigated using XRD, FE-SEM, BET, ICP, EDS, TEM, HRTEM, XPS, and UV-vis spectroscopy. The results indicated that Co~(2+) ion could change the particle nucleation process and inhibited the particle growth of FeS_2. In addition, when the content of doped Co~(2+) was 15%, the degradation efficiency of methylene blue(MB) achieved 60.72% after 210 min irradiation, which increased by 52.01% than that of the undoped FeS_2. Moreover, comparison experiments also demonstrated that the M(M=Co~(2+), Co~(2+)/Ni~(2+))-doped FeS_2 photocatalytic activity efficiency sequence was Co~(2+) Ni~(2+)Co~(2+)/Ni~(2+). This is ascribed to the fact that the Co~(2+) doping could induce the absorption edge shifting into the visible-light region and increased the surface area of the samples. The effect mechanisms of M-doping on the band gap and the photocatalytic activity of FeS_2 were also discussed.     

Microwave absorbing properties and magnetic properties of different carbon nanotubes

The microwave absorbing properties and magnetic properties of as-grown Fe-filled carbon nanotubes (CNTs), annealed Fe-filled CNTs, and multi-walled CNTs were studied. Vibrating sample magnetometer results showed that the annealed Fe-filled CNTs have the weakest coercivity and strongest saturation magnetization among the three types CNTs, due to the presence of more ferromagnetic α-Fe nanowires. After annealing, the values increased to 291.0 Oe and 28.0 emu/g and the samples showed excellent microwave absorbing properties. The reflection loss was over 5 dB between 11.6 GHz and 18 GHz with a maximum value of 10.8 dB for annealed Fe-filled CNTs (1.1 wt%)/epoxy composite.     

钨晶须制备及生长机理研究

以93W-4.9Ni-2.1Fe混合粉末为原料,采用无衬底和钼(Mo)衬底两种条件制备钨(W)晶须,并探讨其生长机理.分别采用扫描电镜、X射线能谱仪、场发射扫描电镜、透射电镜和X射线衍射仪对产物形貌、元素分布和物相等进行测试分析.研究表明,在无衬底和Mo衬底条件下均能得到表面形貌良好,无明显缺陷,直径约200~400 nm,长径比达100以上的W晶须,且Mo衬底能促进W晶须的生成,少量的Mo原子进入W晶格,可取代晶胞中的W原子,形成连续固溶体,使晶胞参数减小.     

等离子体化学气相沉积制备氮化碳薄膜

以H2、N2和CH4气体为前驱气体,通过等离子体化学气相沉积技术制备氮化碳薄膜。采用场发射扫描电子显微镜(FS-EM)及其附带的能量分散电子谱(EDS)、X射线衍射分析(XRD)、红外光谱(FTIR)和拉曼光谱(Raman)对其结构、表面形貌、元素含量和成键状况进行了分析,并讨论了气体流量比和放电功率对薄膜制备的影响。实验结果表明:沉积的薄膜中含有晶态的C3N4,碳氮原子比接近于理论值0.75,样品中碳氮原子多以C N、C N的形式存在;样品中氮元素的含量随着反应气体中N2含量的增加而增加;放电功率的增大使薄膜的沉积速率增大。     

FeTiNbMoW高熵合金的组织和性能

为了研究一种能够吸收γ射线的含W合金的性能,按照等摩尔比设计了一种FeTiNbMoW五组元高熵合金.利用X射线衍射仪、扫描电子显微镜、能谱仪、显微硬度计、密度仪和万能力学试验机对合金的晶体结构、微观组织、成分、硬度、密度和压缩性能进行了分析.结果表明,FeTiNbMoW高熵合金组织由简单BCC固溶体基体和分布其上的少量金属间化合物组成.BCC结构的实际晶格常数为0.315 5 nm,组织形貌为典型枝晶组织.枝晶硬度和枝晶间硬度分别为830.05和793.04 HV.合金的实测密度为10.7 g/cm3,略高于其理论值10.21 g/cm3.室温下合金的抗压强度和对应塑性应变分别为604 MPa和3.19%.合金呈粉末性断裂,其断裂机制为解理断裂.     

纳米碳纤维掺杂量与取向对纳米碳纤维/乙烯-醋酸乙烯酯复合材料介电性能的影响

通过微波法化学镀镍对纳米碳纤维(CNFs)进行表面改性,采用熔融共混法将表面改性的CNFs与乙烯-醋酸乙烯酯(EVA)复合制备CNFs/EVA复合材料,在模压交联过程中对复合材料施加磁场,使表面镀镍的CNFs在复合材料基体中沿磁场方向取向;用场发射扫描电子显微镜(FE-SEM),透射电子显微镜(TEM)和X射线衍射仪(XRD)观察表面改性前后CNFs表面形貌和结构、复合材料内部微观结构及取向情况;用宽频介电谱仪与阻抗谱仪对复合材料进行介电谱测试,研究了CNFs的取向与掺杂量对复合材料介电性能的影响,并用四探针法测量复合材料的体电阻率。研究结果表明,掺杂量和是否取向对复合材料介电性能影响较大;CNFs掺杂质量分数为0.5%时,取向复合材料相对介电常数最低,施加磁场取向不会增加复合材料的介电损耗,少量掺杂即可大幅降低复合材料的体电阻率。