Surface Modification With Zinc and Zn-Ni Alloy Compositionally Modulated Multilayer Coatings

Zinc and Zn-Ni alloy compositionally modulated multilayer （CMM） coatings were electrodeposited on to a steel substrate by the successive deposition of zinc and Zn-Ni alloy sublayers from dual baths. The coated samples were evaluated in terms of the surface appearance, surface and cross-sectional morphologies, as well as corrosion resistance. The microstructural characteristics that were examined using the field emission gun scanning electron microscopy （FEGSEM） confirmed the layered structure, grain refinement of the zinc and Zn-Ni alloy CMM coatings, and revealed the existence of microcracks caused by the internal stress in the thick Zn-Ni alloy sublayers. The corrosion resistance that was evaluated by means of the salt spray test shows that the zinc and Zn-Ni alloy CMM coatings were more corrosion-resistant than the monolithic coatings of zinc or Zn-Ni alloy of the same thickness. The possible reasons for the better protective performance of Zn-Ni/Zn CMM coatings were given on the basis of the analysis on the micrographic features of zinc and Zn-Ni alloy CMM eoatings after the corrosion test. A probable corrosion mechanism of zinc and Zn-Ni alloy CMM coatings was also proposed.

Corrosion Performance of Zinc and Zinc-cobalt Alloy Compositionally Modulated Multilayer (CMM) Coatings

Varieties of zinc and Zn-Co alloy compositionally modulated multilayer （CMM） coatings were electrodeposited onto steel substrates using dual bath technique. The surface and cross-sectional morphologies of coated samples were examined using scanning electron microscopy （ SEM ）. The existence of iuternal stress in ZnCo alloy deposits was confirmed by the cross-sectional morphalogies for the occurrence of micro-cracks in the thick Zn-Co alloy deposit alone. The corrosion performance was evaluated using neutral salt spray testing, corrosion potential measurement and anodic polarization methods. The experimental results slum, that the zinc and Zn- Co alloy CMM coatings were more corrosion-resistant than the monolithic coatings of zinc or Zn-Co alloy alone with a similar thickness. The analysis on the micrographic features of zinc and Zn-Co alloy CMM coatings, using field emission gun scanning electron microscopy （FEGSEM） after corrosion testing, explains the probable reusons why the Zn-Co/ Zn CMM coating system has a better protective performance.

Electrodeposition of Compositionally Modulated Zinc-cobalt Alloy Multilayer Coatings

The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Average current density and reverse anodic current density amongst the variables investigated have very strong effects on the cobalt content in the Zn-Co alloy deposits. Grain size, surface appearance and internal stress in the deposit were improved significantly by introducing the reverse current. Varieties of Zn-Co alloy compositionally modulated multilayer (CMM) coatings with large differences in cobalt contents for different sublayers were electrodeposited by designing corresponding waveforms using a computer-aided pulse plater and characterized in terms of surface morphologies. Cross-sectional morphologies of the Zn-Co alloy CMM coatings, examined using field emission gun scanning electron microscopy (FEGSEM), confirmed the layered structure.

Low insertion loss silicon-based spatial light modulator with high reflective materials outside Fabry–Perot cavity

The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.

Corrosion behaviors of zinc and Zn-Ni alloy compositionally modulated multilayer coatings

Zinc and Zn-Ni alloy compositionally modulated multilayer （CMM） coatings were electrodeposited from dual baths. The coated samples were evaluated in terms of surface appearance, surface and cross-sectional morphologies, as well as corrosion resistance. The results obtained from the salt spray test show that the zinc and Zn-Ni alloy CMM coatings are more corrosion-resistant than the monolithic coatings of zinc or Zn-Ni alloy alone with a similar thickness. The corrosion potential measurement and anodic polarisation tests were undertaken to examine the probable corrosion mechanisms of zinc and Zn-Ni alloy CMM coatings. Analysis on the micrographic features of zinc and Zn-Ni alloy CMM coatings after the corrosion test explains the probable reasons why the Zn-Ni/Zn CMM coatings have a better protective performance. Surface morphologies and compositional analysis of the remaining coating material of Zn-Ni alloy deposit after the corrosion test confirms the dezincification mechanism of the Zn-Ni alloy deposit during the corrosion process.

Structure and tribological properties of Si/a-C:H(Ag)multilayer film in stimulated body fluid

Si/a-C:H(Ag)multilayer films with different modulation periods are prepared to test their potential applications in human body.The composition,microstructure,mechanical and tribological properties in the simulated body fluid are investigated.The results show the concentration of Ag first decreases and then increases with the modulation period decreasing from 984 nm to 250 nm.Whereas the C content has an opposite variation trend.Notably,the concentration of Ag plays a more important role than the modulation period in the properties of the multilayer film.The a-C:H sublayer of the film with an appropriate Ag concentration(8.97 at.%)(modulation period of 512 nm)maintains the highest sp3/sp2 ratio,surface roughness and hardness,and excellent tribological property in the stimulated body fluid.An appropriate number of Ag atoms and size of Ag atom allow the Ag atoms to easily enter into the contact interface for load bearing and lubricating.This work proves that the Ag nanoparticles in the a-C:H sublayer plays a more important role in the tribological properties of the composite-multilayer film in stimulated body fluid condition.

调制周期对AlCrSiN/AlCrMoSiN多层膜微结构和性能的影响

目的通过优化AlCrSiN/AlCrMoSiN多层复合涂层的调制周期,提升涂层的力学性能和摩擦学性能。方法采用高功率脉冲磁控溅射与脉冲直流磁控溅射复合技术,固定调制比为5∶1,制备具有不同调制周期的AlCrSiN/AlCrMoSiN多层复合涂层。利用XRD和SEM分析涂层物相组成,观察其微观形貌;借助纳米压痕仪、划痕仪、高温摩擦试验机及轮廓仪测试涂层的硬度、弹性模量、临界载荷,以及摩擦磨损性能。结果掺杂Mo元素后,AlCrMoSiN层生成了大量的非晶相,并观察到沿AlN(111)晶面共格外延生长。AlCrSiN/AlCrMoSiN多层复合涂层表面颗粒随着调制周期的增大逐渐变小,整体呈“花椰菜”状,且致密、无缺陷。随着调制周期的增大,硬度、H/E和H^(3)/E^(*2)呈先升高后降低的趋势;涂层的平均摩擦因数呈先降低后升高的趋势。当调制周期为145 nm(AlCrSiN层厚度约为120 nm,AlCrMoSiN层厚度约为25 nm)时,多层涂层中层间界面清晰,涂层的硬度最高,约为24.9GPa,摩擦因数和磨损率均最低,分别为0.57、1.46×10^(-6)mm^(3)/(N·m),临界载荷为75.8N。结论多层复合涂层的调制周期对其结构和性能具有重要影响,当调制周期为145nm时,AlCrSiN/AlCrMoSiN多层复合涂层具有最佳的综合性能。

调制周期数对Mo/AZO成分调制多层膜透光、反光特性以及电性能的影响

采用射频(RF)和单极中频脉冲直流(UMFPDC)磁控溅射技术,在300℃下制备了Mo/AZO成分调制多层膜。测试结果表明,Mo/AZO成分调制多层膜以(002)为取向的六方纤锌矿型ZnO结构为主;薄膜中Mo的化学态随薄膜厚度而变化,当薄膜厚度为1.67 nm时,Mo除单质态外,还存在部分+4和+5的离子价态,当薄膜厚度降至0.83 nm时,已无单质态Mo;调制周期数对成分调制多层膜的透光、反光特性以及电性能影响显著,当调制周期数为3时,Mo/AZO成分调制多层膜的综合性能达到最佳,电阻率、霍尔迁移率和载流子浓度分别为8.64×10^(-4)Ω·cm、8.78 cm^2)/(V·s)和8.23×10^(20)cm^(-3)。在保持金属层、半导体层总厚度不变的情况下,通过改变调制周期数可以增加薄膜的光学透过率并可在较宽范围内调节多层膜的综合性能,这为制备综合性能优异的金属/半导体型透光导电薄膜提供了一条切实可行的途径。

调制周期对CrN_(x)/TiAlSiN多层涂层抗冲蚀性的影响

目的在砂粒环境下,改善TiAlSiN硬质涂层于高角度下的抗冲蚀性能。方法采用电弧离子镀复合高功率脉冲磁控溅射技术,制备不同调制周期下的CrN_(x)/TiAlSiN多层涂层。应用电子扫描电镜、X射线衍射仪、纳米压痕仪和划痕仪对涂层的显微结构、物相组成、纳米硬度、弹性模量以及结合力进行分析,于冲蚀试验平台对涂层抗冲蚀性能进行评价(Al_(3)O_(2)砂粒平均粒径为50μm,冲蚀速度为30 m/s,角度为90°)。结果涂层结构致密,由面心立方结构c-(Ti,Al)N、c-Cr、c-CrN和六方h-Cr_(2)N相构成。随着CrN_(x)子层结构的引入,TiAlSiN子层对应的(220)取向逐渐消失,(111)衍射晶面逐渐呈现。随着调制周期减少,CrN_(x)子层对应的h-Cr_(2)N(300)和c-CrN(220)衍射峰强度表现出先逐渐降低、后缓慢增加的规律。涂层结合变化幅度不大,处于68~71 N。虽然纳米硬度和弹性模量逐渐下降,分别从(37.5±0.46)GPa和(339.92±1.85)GPa下降至(31.2±0.40)GPa和(267.50±7.98)GPa,但H/E韧性指标逐渐增加,从0.110增加至0.116。在最小调制周期下,涂层表现出最优抗冲蚀性能,其冲蚀速率仅TiAlSiN硬质涂层的1/5。结论调制周期的减少增加了涂层界面数目,对扩展的裂纹起到了很好偏转作用,提升了涂层韧性,贡献了涂层抗冲蚀性能。在砂粒反复冲击作用下,于涂层中产生了交互作用的横纵裂纹,致使涂层以碎屑脆性剥落机制而失效,破坏特征表现为逐层剥落。

电弧离子镀TiN/ZrN多层膜力学性能研究

采用电弧离子镀制备了调制比和总厚度一定,周期数不同的一系列TiN/ZrN多层膜,研究了周期数对多层膜力学性能的影响。使用X射线衍射仪、扫描电子显微镜分析了多层膜的结构形貌,利用显微硬度计、往复摩擦试验机和多功能材料表面性能试验仪测试了薄膜的力学性能和摩擦学性能。结果表明,多层膜都呈现单一的面心立方结构,以柱状晶结构生长,表面致密光滑,界面效应明显,力学性能受到界面结构和择优取向的影响,当周期数为50时,TiN具有明显的(200)择优取向,多层膜的硬度达到最大值2568 Hv,多层膜的摩擦学性能受到表面形貌和硬度的影响,当周期数为40时,具有最低的摩擦系数为0.47,磨损率随着硬度的增加而减少,在50周期时的磨损率为6.9×10^(-6)mm^(3)·N^(-1)·m^(-1),耐磨性最佳。

高隔离SAW双工器模组的研制

为进一步提高LTE B3双工器频段间隔离度,利用系统级封装(SIP)技术设计了一种高隔离声表面波(SAW)双工器模组。该模组由2个SAW双工器和3个耦合器组成,利用TX-RX路径的相位相消及耦合器的隔离度,实现单颗SAW双工器上下行链路间隔离度的提高。采用阻抗元滤波器架构,实现了单颗SAW双工器隔离度达51 dB。采用宽边带状线多层螺旋耦合线结构实现了工作宽带宽、集成小型化的3 dB耦合器。研制的模组测试结果表明,在B3频段内,尺寸为8.0 mm×8.0 mm×2.0 mm,插入损耗小于3.2 dB,回波损耗大于13 dB,隔离度优于65 dB,承受瞬间功率可达34 dBm。

多层硅基模块晶圆级键合腔体的可靠性

晶圆级键合是实现多层硅基模块内部互连的关键工艺,针对硅片在晶圆级键合工艺中的开裂现象,建立了硅基刻蚀腔体在键合工艺中的力学模型,经样件实验验证,该模型可以准确预估腔体的开裂现象。在此基础上设计了硅片键合实验,通过引入硅通孔(TSV)的应力集中因子确定了硅基晶圆级键合的应力失效判据。而后通过参数化仿真系统性探究了硅基刻蚀腔体面积及腔体形状等因素对键合应力的影响规律,并绘制出刻蚀腔体设计可靠范围图。结果表明,硅片键合可靠腔体临界面积约为21 mm^(2),且腔体形状越接近正方形越易开裂。该研究为多层硅基模块刻蚀腔体的可靠性设计提供了参考。

调制周期与调制比对Cu/Nb纳米多层膜结构和性能的影响

为研究调制周期λ和调制比η对Cu/Nb纳米多层膜结构和性能的影响,用磁控溅射沉积Cu/Nb多层膜,λ=30~150 nm,η=1、1.5及2。多层膜微观结构与形貌用X射线衍射仪、扫描电镜及原子力显微镜分析,性能用微力拉伸仪、纳米压痕仪及四探针仪测试。结果表明,Cu/Nb多层膜的结构和性能受控于λ和η。Cu和Nb层分别呈Cu(111)和Nb(110)织构,且均为纳米晶结构。在Cu/Nb界面处,Cu扩散进入Nb层。表面Cu层颗粒尺寸随Cu层增厚而增大。随λ或η减小,Cu/Nb多层膜的屈服强度σ_(0.2)、显微硬度H和电阻率ρ都呈增加趋势。而裂纹萌生临界应变ε_(c)则与1/λ或η呈正相关。

Electro-optical dual modulation on resistive switching behavior in BaTiO3/BiFeO3/TiO2 heterojunction

The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide(FTO) substrate by the sol–gel method. The results indicate that the Pt/Ba TiO3/BiFeO3/TiO2/FTO heterojunction exhibits stable bipolar resistive switching characteristic, good retention performance, and reversal characteristic. Under different pulse voltages and light fields, four stable resistance states can also be realized. The analysis shows that the main conduction mechanism of the resistive switching characteristic of the heterojunction is space charge limited current(SCLC) effect. After the comprehensive analysis of the band diagram and the P–E ferroelectric property of the multilayer heterojunction, we can deduce that the SCLC is formed by the effect of the oxygen vacancy which is controlled by ferroelectric polarizationmodulated change of interfacial barrier. And the effective photo-generated carrier also plays a regulatory role in resistance state(RS), which is formed by the double ferroelectric layer Ba TiO3/BiFeO3 under different light fields. This research is of potential application values for developing the multi-state non-volatile resistance random access memory(RRAM) devices based on ferroelectric materials.

基于二次调制原理的多层结构绝对式角位移传感器

为了在传感器径向尺寸不变的前提下,保持良好的测量精度和分辨率,以适应小型化需要的工业场合,提出了一种利用多层结构实现信号二次调制的圆时栅角位移传感器。传感器为3层结构,利用轴向空间,使内外环分别通过多层结构完成信号的二次调制,其中内环作为粗测环经二次调制后用于实现传感器的绝对定位,外环作为精测环经二次调制后,提高了传感器分辨率。采用PCB工艺制造了外径Φ=100 mm,内径Φ=50 mm的传感器样机,初步实验表明内外环同时施加激励时,内外环将分别受到对方产生的串扰影响,因此进一步提出分时施加激励的优化方法避免信号串扰的影响以提升测量精度。最终实验结果表明传感器能够实现绝对定位且分辨率提升了1倍,原始测量精度达到了±4.1″。

混压多层印制板多芯片收发组件关键技术研究

作为有源相控阵天线阵面的核心部件,收发组件在整个有源天线阵面中的成本占比最高,因此如何降低收发组件的成本是设计天线阵面需要着重考虑的问题。与多芯片收发组件中常用的低温共烧陶瓷(Low Temperature Co-fired Ceramic,LTCC)多层基板相比,多层印制板在成本方面具有很大优势。文中利用混压多层印制板,结合铝合金封装壳体,研制了一款Ku波段四通道低成本收发组件。该收发组件在工作频带内可以实现6位移相和6位幅度衰减,其通道接收增益≥20 dB,通道发射功率≥10 W。文中针对混压多层印制板热膨胀系数高、布线密度低、金丝键合可靠性差等问题,优化了基板叠层方案,研究了高密度互联通孔制作、基板镀层高可靠键合、低成本气密封装等关键工艺技术,有效提升了产品的可靠性,可为低成本混压多层印制板在多芯片组件中的工程化应用提供参考。

国产LTCC微波多层基板中的电阻埋置技术

国产埋置电阻浆料采用了具有自主知识产权的材料配方和制备工艺,其浆料粘度、触变性等与进口浆料相比存在差异。为探究国产埋置电阻浆料的工程应用前景,对其进行应用技术研究。首先介绍了埋置电阻浆料的性能以及埋置电阻工艺参数与电阻阻值之间的关系,然后通过50Ω负载电阻、π型衰减器和低温共烧陶瓷(Low Temperature Co-fired Ceramic,LTCC)微波多层基板验证了埋置电阻的性能。结果表明,通过设计优化和关键工艺参数控制,埋置电阻的阻值精度和微波性能能够满足X波段收/发(Transmit/Receive,T/R)组件技术要求,可以实现国产埋置电阻浆料的工程应用。

15-5PH不锈钢表面类石墨碳基多层膜结构设计及摩擦学行为

针对马氏体沉淀硬化不锈钢15-5PH(0Cr15Ni5Cu4Nb)在海水环境中易腐蚀磨损的问题,采用直流磁控溅射的方法在15-5PH钢样片上制备调制周期分别为940、375和234nm的掺杂Cr的类石墨碳基多层膜(分别标记为Cr/GLC-S1、Cr/GLC-S2和Cr/GLC-S3),采用扫描电子显微镜(SEM)、拉曼光谱仪(Raman)、MFT-5000多功能摩擦磨损试验机等仪器设备系统考察三种类石墨碳基多层薄膜的结构及摩擦学性能。研究结果表明:不同调制周期的类石墨多层膜表面均呈现“菜花状”形貌,随着调制周期的减小,“菜花状”颗粒逐渐减小,膜层变得致密;sp2键含量逐渐增大,石墨化程度加剧,机械性能更加优异。在干摩擦条件下,调制周期适中的Cr/GLC-S2薄膜具有良好的减摩耐磨性能,磨损形式以磨粒磨损为主,而调制周期较大的Cr/GLC-S1和调制周期较小的Cr/GLC-S3薄膜,在高载荷下均发生不同程度的脆性剥落,导致其摩擦学性能劣化。在人工海水环境中,Cr/GLC-S1和Cr/GLC-S2薄膜在中低载荷下的摩擦学性能较好,磨损形式仍以磨粒磨损为主,在高载荷下三种多层膜均发生不同程度的脆性剥落,特别是调制周期较小的Cr/GLC-S3薄膜已失效。针对不同的工况,设计合理的调制周期是提高GLC薄膜摩擦学性能的关键,结果可为类石墨碳基薄膜在海洋防护中的实际应用提供一定参考。

微纳米尺度薄膜/基底材料残余应力研究进展

残余应力是功能失效的主要原因,它可能导致薄膜形状发生重大变化,甚至产生分层、屈曲和裂纹。这不仅会破坏器件的结构完整性,而且直接影响到薄膜光学、电学、力学等物理性质,导致严重缩短使用寿命。为了研究薄膜特征参数与残余应力的关系,本文首先概述了微纳米尺度薄膜/基底体系中残余应力的机理模型及测试方法。然后,在单层膜领域,综述了沉积条件、薄膜厚度、工艺参数(溅射功率、工作压力、基底温度、退火状态)等因素对薄膜残余应力的影响;在多层膜领域,介绍了调制周期、缓冲层对薄膜残余应力分布的作用。最后展望了薄膜/基底体系残余应力研究的发展方向,指出应该从机理模型、应力分布规律以及探索功能材料的残余应力等方向开展研究。

基于多层长短期记忆神经网络的用水量预测

及时准确的居民用水量预测对供水系统的设计和运行管理至关重要。长短期记忆神经网络(LSTM)是一种有效的基于数据驱动的用水量预测模型,但其通常依赖于大量的参数设置。因此,在LSTM模型基础上,通过叠加时间分布模块,提出多层长短期记忆神经网络模型(MLSTM)。与LSTM模型对比分析表明,MLSTM模型具有较低复杂度和更高的预测精度,尤其对于高峰期用水量预测(M_(MAPE)值降低约60%),且受外部环境条件(如天气)的影响较小。