Application of face centred cubic TiB powder as conductive filler for electrically conductive adhesives

Face centred cubic（FCC） TiB ceramic powder synthesized by Ti-boronizing method was used as conductive filler to make ceramic electrically conductive adhesives（ECAs） with the polymer matrix.Electrically conductive properties of the ceramic ECAs were studied.The bulk electrical resistivity varied with the powder content of the FCC-TiB in ECAs.The FCC-TiB filled ECAs also showed the percolation behavior that usually occurred for the metal-filled ECAs,the percolation threshold was located at the content of 60%FCC-TiB.A minimum value of 0.1 Ω·cm was obtained at a content of 75%FCC-TiB.In order to check the reliability of mechanical property,tensile test was done to measure the shear strength,and the shear strength dropped with increasing the content of FCC-TiB powders.It is about 12.26 MPa at the content of 70%TiB powders.The Cu filled ECAs were also prepared for comparison.The properties of the oxidation resistance of the two ECAs were evaluated.The results show that the ceramic ECAs have excellent oxidation resistance and better stability compared with the Cu filled ECAs.

Electrochemical migration behavior of Ag-plated Cu-filled electrically conductive adhesives

The electrochemical migration (ECM) behavior of the electrically conductive adhesives (ECAs) filled with pure Ag powder or Ag-plated Cu composite powder with varied Ag:Cu ratios was investigated under the condition of applying constant voltage and distilled water environment.ECM resistance was determined from the current-time curves.The microstructure and composition of ECM dendrite products were analyzed by SEM/EDS and XRD.It was found that the ECM resistance of Ag-plated Cu composite powder-filled ECAs was evidently higher than that of pure Ag powder-filled ECAs.The Ag:Cu ratio of composite powder in ECAs had notable influence on ECM resistance,which was enhanced with the decrease of Ag:Cu ratios.The composition of dendrites formed between cathode and anode during ECM process was not uniform for Ag-plated Cu-filled ECAs.An ECM inhibiting mechanism of Ag-plated Cu composite powder was proposed according to analysis of the electrochemical impedance spectroscopy,Tafel plot and dendrite composition.

Application of silver nanoparticles in electrically conductive adhesives with silver micro flakes

This study has been conducted to evaluate the application of silver nanoparticles(NPs)in Electrically Conductive Adhesives(ECAs),filled with hybrid silver flakes and NPs,and silver flakes as a control sample,at a filler loading of 78 wt.%,83 wt.%and 88 wt.%and cured at 150℃and 180℃,respectively.The results show that the electrical and thermal conductivities of ECAs were improved with the increasing of filler loading and curing temperature.Adding silver NPs in silver flakes negatively affected the electrical and thermal conductivities of ECAs at a low filler mass fraction of 78 wt.%,because the segregation of NPs enlarged the average distance of silver flakes;while it positively influenced the electrical and thermal conductivities of ECAs at a loading ratio of 88 wt.%,probably due to NPs filling in the gaps between silver flakes or even sintering together with each other or with silver flakes,especially when curing at high temperature of 180℃.

Electrically Detaching Behavior and Mechanism of Ionic Conductive Adhesives

Design of rapidly detachable adhesives with high initial bonding strength is of great significance but it is full of great challenge. Here, we report the fast electrically detaching behavior (100% detaching efficiency in just 1 min under dozens of DC voltage) and high initial bonding strength (>12 MPa) of epoxy-based ionic conductive adhesives (ICAs). The epoxy-based ICAs are fabricated by introducing polyethylene glycol dimethyl ether (PEGDE) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM]OTF) into epoxy. The combination of PEGDE and [EMIM]OTF enables the free ions to migrate directively in electric field, and the anchoring of PEG chains onto epoxy chains ensures the long-term reliability of ICAs. The investigation on the electrically detaching mechanism suggests that the enrichment and following rapid interfacial electrochemical reactions of [EMIM]OTF lead to formation of metal hydroxide (Me(OH)n) nanoparticles at the bonding interfaces, thus the strong interactions containing interlocked forces, van de Waals’ forces and hydrogen bonding interactions between ICAs and bonding substrates are destroyed. This work provides a promising direction for detachable adhesives with both high initial bonding strength and high detaching efficiency in short time.

Thermoelectric Behavior of Isotropically Conductive Adhesive

The paper deals with unusual use of one kind of ECA （electrically conductive adhesive）---the ICA （isotropic conductive adhesive）. The main sphere of ECA application is electronic assembly, e.g., it is bonding of semiconductor microchips on printed circuits boards. In this sphere, the ECA compete with soft solder. In spite of this fact, the author utilized of two main ECA characteristics--good electrical conductivity and excellent adhesion to material surfaces to make the fiat thermocouples. Both the design of thermocouples and the measuring device and the measuring workplace arrangement are described. The measured data of thermoelectric voltages are plotted. The thermoelectric （Seebeck＇s） coefficients were calculated from obtained dependences of thermoelectric voltage versus the temperature differences.

STUDY ON THE STRUCTURE, ELECTRICAL PROPERTIES AND CONDUCTION MECHANISM 0F THE MULTICRYSTAL MULTIPHASE MATERIAL Li_2MO_2-xWxO_6

The conductivity of non-crystalline fast ionic conductor for B_2O_3-Li_2O-LiCl-Al_2O_3 system is studiedin this paper. The glass structure of this system is discussed by means of infrared spectrum and X-ray fluorescence analysis, and the effects of LiCl and A1_2O_3 on the conductivity of Li^+ in the system are studied as well. Adding Li_2O to the system gives rise to transfer from [BO_3] triangular units to [BO_4] tetrahedral. When Li_2O content exceeds 30mol%, the main group of the glass is the diborate group with more [BO_4] tetrahedra. The adding of LiCl has no obvious influence on the glass structure, and LiCl is under a state dissociated by network, but with the increase of LiCl, the increase of conductivity is obvious. By adding A1_2O_3, the glass can be formed when the room-temperature is cooling down,the conductivity decreases while the conductive activatory energy increases for the glass. The experiment shows that conductivity in the room-temperature is σ= 6.2×10^(-6)Ω^(-1)cm^(-1), when at 300℃, the σ=6.8×10^(-3)Ω^(-1)cm^(-1). The conductive activatory energy computed is 0.6～1.0eV.

Influence of anisotropy on the electrical conductivity and diffusion coefficient of dry K-feldspar： Implications of the mechanism of conduction

The electrical conductivities of single-crystal K-feldspar along three different crystallographic directions are investigated by the Solartron-1260 Impedance/Gain-phase analyzer at 873 K–1223 K and 1.0 GPa–3.0 GPa in a frequency range of 10-1 Hz–106 Hz. The measured electrical conductivity along the ⊥ [001] axis direction decreases with increasing pressure, and the activation energy and activation volume of charge carriers are determined to be 1.04 ± 0.06 e V and 2.51 ± 0.19 cm~3/mole, respectively. The electrical conductivity of K-feldspar is highly anisotropic, and its value along the⊥ [001] axis is approximately three times higher than that along the ⊥ [100] axis. At 2.0 GPa, the diffusion coefficient of ionic potassium is obtained from the electrical conductivity data using the Nernst–Einstein equation. The measured electrical conductivity and calculated diffusion coefficient of potassium suggest that the main conduction mechanism is of ionic conduction, therefore the dominant charge carrier is transferred between normal lattice potassium positions and adjacent interstitial sites along the thermally activated electric field.

Damping Properties of Piezoelectric and Electrical Conductive of BaTiO_3/VGCF/CPE Composites: Effect of Carbon Fiber

A new damping composite of CPE/BaTiO3/VGCF has been developed on the basis of the piezo- effect and conductivity mechanism. The conductivity of composites varied with the VGCF content are tested and analyzed.The results indicate that the conductivity of composites grows up slowly as the VGCF content is in the range of 10%-20%. It is very useful for industrial application to control the conductivity of composites by adjusting the VGCF content. In addition, at the range of - 50 - 120°C,the dependence of loss factor on the VGCF content varied with the temperature are tested and analyzed by dynamic mechanical and dielectric behavior measurement of the composites, and expected results are obtained.

Design and Characterization of Electrical Connections for Conductive Yarns

The development of flexible and stretchable electronics has attracted much attention.As an important part of wearable electronic systems,the connection between conductive yarns and electronic components affects the stability and accuracy of their electrical reliability.In this paper,three different connections were attempted to electrically and mechanically link two conductive yarns,including soldering followed by waterborne polyurethane(WPU)encapsulation,coating of conductive silver adhesive with WPU encapsulation,as well as coating of conductive silver adhesive with polydimethylsiloxane(PDMS)encapsulation.The surface morphologies and electro-mechanical behaviors of the three created connected conductive yarns were characterized.Compared with their electro-mechanical behaviors of the established three connections,the connection with soldering remained electrically conductive to around 200%,which mainly came from the stress concentration between the stiff soldering and soft conductive yarns.However,the coating of conductive silver adhesive and encapsulated protection of PDMS can make the connected conductive yarns stretchable up to 300%with almost constant electrical resistance.

机械深松对苏打盐碱土盐碱特征及玉米生长的影响

以苏打盐碱土为研究对象,设置常规耕作不深松(CK)、机械深松30 cm(S30)和机械深松40 cm(S40)3种耕作处理,采用田间大区试验研究了机械深松耕作对苏打盐碱土不同土层盐碱特征及玉米生长的影响。结果表明:S30和S40处理中0~10、10~20、20~30、30~40、40~50 cm各层土壤电导率(EC)和pH均低于CK处理,整体上看,S40处理各层土壤平均EC和pH下降幅度大于S30处理;机械深松耕作显著提高了玉米植株株高、穗位高、穗长、穗粗、行粒数和籽粒产量,对植株茎粗和秃尖长无显著影响,S40处理玉米作物长势好于S30处理(P<0.05);S30、S40处理籽粒产量分别为8542.87、9020.33 kg/hm2,比CK处理分别高16.40%、22.90%。综上所述,机械深松耕作可以有效削弱苏打盐碱土盐害和碱害,改善土壤性状,促进玉米作物的生长,深松40 cm效果优于深松30 cm。

基于无颗粒银导电墨水在不锈钢表面镀银工艺研究

目的采用无颗粒银导电墨水对不锈钢表面进行镀银研究,以绿色环保工艺替代传统电镀银技术。方法主要研究适用于不锈钢基材的前驱体银源、络合剂种类、不锈钢前处理方法、烧结固化温度对不锈钢表面银层微观结构及性能的影响,获得不锈钢基材上微观结构致密、性能良好的银层。采用X射线衍射仪、扫描电子显微镜、激光共聚焦显微镜、数字兆欧表对在不锈钢表面银膜层进行表征。结果不锈钢通过1,2丙二胺溶液处理后,采用银源草酸银为前驱体,此时银层微观结构最致密,具有最佳的附着力等级(5B)和最低的粗糙度(1.237μm),与1,2-丙二胺络合,乙醇为溶剂时,制备出的银层有机物挥发完全,微观结构致密,并且具有最低的接触电阻0.7Ω和粗糙度0.80μm。烧结固化温度为200℃时银层导电性最好。结论采用无颗粒银导电墨水对不锈钢表面进行镀银的新型工艺银层性能良好,可以简化传统电镀技术复杂的操作流程,减少传统电镀工艺所使用氰化物对人体造成的危害,并弥补应用受限的缺点。

智能混凝土裂缝自监测性能试验研究

为了对建筑物的裂缝进行实时监测,掌握建筑物的裂缝扩展情况及开裂位置对加入导电相材料(钢纤维和纳米炭黑)后智能混凝土的力学性能、导电性能以及自监测性能进行研究,并改变导电相材料的掺量,分析其对抗压强度、电阻变化率等性能指标的影响。结果表明,在满足力学性能和导电性能的前提下,复掺纳米炭黑与钢纤维可以发挥钢纤维长程导电与纳米炭黑短程导电的互补优势,使材料具备良好的自监测性能,且钢纤维掺量为1.50%、纳米炭黑掺量为0.75%时,裂缝自监测性能最佳。

石墨烯和碳纳米管增强铜基复合材料的研究进展

本文回顾了碳纳米管(CNT)和石墨烯(Gr)增强铜基复合材料的研究进展,探讨了这些复合材料的制备方法、性能提升机制及潜在应用前景。CNT和Gr因独特的物理化学特性,作为铜基复合材料的理想增强相,显著提升了材料的力学性能、导电性和热导率。首先回顾了铜基复合材料的传统制备技术,包括粉末冶金法和机械合金化法,随后介绍了新兴的化学气相沉积(CVD)和电沉积法,这些技术通过直接生长或电化学沉积实现更好的界面结合。对比分析了不同方法的优缺点,指出粉末冶金和机械合金化的成本较低但可能引起增强相分布不均,而CVD法虽能制备高质量材料但成本较高且环境影响敏感。进一步分析了CNT和Gr在铜基体中的分散性及界面结合对性能的影响,强调了良好分散性和强界面结合的重要性。在力学性能方面,CNT和Gr的分散性和界面结合对复合材料的强化机制起着关键作用,包括载荷转移、晶粒细化和Orowan强化等。此外,讨论了CNT和Gr增强铜基复合材料在耐腐蚀性、磨损性能及热管理等方面的应用潜力。尽管存在挑战,但这些复合材料在电力传输、电子器件和航空航天等领域显示出巨大应用前景。未来的研究将集中于微观结构控制、制备工艺创新和多功能复合材料开发,以实现更高性能的工业应用。

Ag含量对低合金化Cu-Ag合金拉拔线材组织和性能的影响

采用热型水平连铸技术制备Ag含量分别为0.6%、1.0%、2.0%和4.0%的Cu-Ag合金杆坯,并将d 16.0 mm杆坯拉拔加工成d 1.0 mm的线材,利用透射电镜分析其微细组织,并测试导电和力学性能。结果表明:拉拔线材由平行于拉拔方向的纤维晶组成,Cu-0.6Ag合金线纤维晶平均宽度约为340 nm;随着Ag含量增加,纤维晶尺寸减小,Cu-4.0Ag合金线纤维晶平均宽度为115 nm。纤维晶存在显著的〈111〉取向,纤维晶晶界主要为由位错塞积形成的小角度晶界,晶内存在大量位错,并发现少量的孪晶。随着Ag含量增加,Ag元素分布由局部富集转变为Ag相析出。Cu-0.6Ag和Cu-4.0Ag合金线材导电率随Ag含量的增大而减小,分别为91.2%IACS和79.5%IACS。Cu-0.6Ag和Cu-4.0Ag合金线材抗拉强度随Ag含量的增加而增大,分别为402.6 MPa和702.9 MPa。抗拉强度提高的主要原因是细晶强化和Ag相沉淀强化作用。

高导电、低逾渗PLA/CNTs导电复合材料的结构设计及性能研究

通过溶液吸附⁃熔融法制备了具有低逾渗高导电性能的左旋聚乳酸/右旋聚乳酸/碳纳米管(PLA/PDLA/CNTs)复合材料。在PLA/CNTs复合材料内部通过添加PDLA以提高复合材料的结晶性能,起到良好的体积排斥作用,促进了CNTs的分散,对PLA/PDLA/CNTs复合材料的导电网络结构进行有效调控;随着PDLA含量的增加,PLA/PDLA/CNTs复合材料的导电性能表现出了先增加后降低的趋势,当PDLA的含量仅为0.2%时,PLA/0.2%PDLA/0.6%CNTs的电导率从10^(-6) S/m提升到了10^(-4) S/m,提高了2个数量级,并且复合材料的导电逾渗值从0.58%(PLA/CNTs)降低到0.45%(PLA/PDLA/0.6%CNTs)。此外,CNTs和PDLA的引入可以有效的提高复合材料的结晶性能和复数黏度,相比于纯PLA,PLA/0.5%PDLA/0.6%CNTs的开始结晶温度(T_(o))和最大峰结晶温度(T_(p))分别提高了30.6℃和20.8℃。通过力学性能数据分析发现,在CNTs和PDLA的协同作用下,PLA/PDLA/CNTs复合材料的拉伸强度得到进一步的改善。因此,在PLA/CNTs复合材料中通过添加PDLA可以对导电网络结构进行有效调控的同时,改善其力学性能,为提升导电复合材料的综合性能提供了新方法。

冷却方式对Cu-10Fe合金铸态组织和性能的影响

采用不同铸造冷却方式(石墨模、水冷铜模)制备Cu-10Fe合金,研究了冷却方式对Cu-10Fe合金铸态组织和性能的影响。结果表明,冷却方式对Cu-10Fe合金抗拉强度和电导率影响显著。采用石墨模时,Fe元素在基体中固溶度降低,促进Fe相析出,对提高合金的电导率有利。采用水冷铜模时,合金组织明显细化,Fe元素在基体中固溶度增加,合金的抗拉强度、硬度显著提高,而电导率小幅下降,其抗拉强度为299.1 MPa,硬度为103.6 HV,电导率49.58%IACS,综合性能良好。

Effect of Zr and Sc on mechanical properties and electrical conductivities of Al wires

In order to obtain the Al wires with good mechanical properties and high electrical conductivities, conductive wires of Al-0.16 Zr, Al-0.16 Sc, Al-0.12Sc-0.04Zr（mass fraction, %） and pure Al（99.996%） were produced with the diameter of 9.5 mm by continuous rheo-extrusion technology, and the extruded materials were heat treated and analyzed. The results show that the separate additions of 0.16% Sc and 0.16% Zr to pure Al improve the ultimate tensile strength but reduce the electrical conductivity, and the similar trend is found in the Al-0.12Sc-0.04 Zr alloy. After the subsequent heat treatment, the wire with the optimum comprehensive properties is Al-0.12Sc-0.04 Zr alloy, of which the ultimate tensile strength and electrical conductivity reach 160 MPa and 64.03%（IACS）, respectively.

La元素对高导热Al-5Ni合金微观组织和性能的影响

Al-5Ni合金具有较高的导热性能,是新一代高导热材料的主要研究方向之一,但力学性能偏低,热-力矛盾显著。利用金相显微镜、扫描电镜、万能试验机、激光导热仪、数字电导率仪等,研究了微量稀土元素La添加对高导热Al-5Ni合金微观组织、力学性能及导热率和导电率的影响。结果表明,当La元素的添加量为0.2%(质量分数)时,合金α-Al晶粒细化程度最高,共晶组织内部纤维状的Al3Ni相近乎全部转化为球状,极限抗拉强度和硬度由未变质时的122.24 MPa和45.94 HV提升到140.48 MPa和47.28 HV,分别提升了14.92%和2.92%;合金的导热率和导电率几乎没有下降,为213.23 W/(m·K)和31.84 MS/m。稀土变质La元素的变质处理有效缓解了Al-5Ni合金的热-力矛盾,显著提高合金的综合性能。

杂原子掺杂石墨烯的制备及应用研究进展

目的综述杂原子掺杂石墨烯的研究进展,对杂原子掺杂石墨烯的未来研究方向进行展望,旨在为杂原子掺杂石墨烯的制备及应用提供参考。方法总结和分析了杂原子掺杂石墨烯的制备方法和潜在应用领域,对比了各种杂原子掺杂对石墨烯电子性质的影响,突出不同元素掺杂的独特性和效果。结果杂原子掺杂不仅提高了石墨烯的电导率和力学强度,还增加了它在特定应用中的稳定性和效率。结论杂原子掺杂石墨烯的发展前景广阔,有望在能源存储、生物医药、环境保护、传感器及印刷包装等领域实现重要突破。

导电胶的研究进展

目的综述电子封装中用于代替锡铅焊料的导电胶的研究进展,对导电胶未来研究方向进行展望,为导电胶的应用提供参考。方法从导电胶的组成、导电机理、类型入手,重点介绍导电胶应用时的关键性能要求与测试方法,并总结近几年在提高导电性、稳定性及降低固化温度、成本等方面的研究进展。结果对导电胶中基体树脂进行改性并选择合适的导电填料(形状、组成),可改善导电胶的固化条件,并提高导电胶的导电性能、黏结性能、耐久性,满足苛刻应用环境下对器件连接高可靠性的要求。结论相比传统铅锡焊料焊接的方式,导电胶具有绿色环保、连接温度低、分辨率高等特点。因此导电胶适用于电子封装与智能包装领域。目前导电胶的研究方向主要为提高导电性、黏结强度以及黏结稳定性。但是在面对固化时间长、耐湿热性弱、成本较高等缺点时,仍需不断优化组成,以满足实际应用要求。