Ag-Pd厚膜电阻的导电机理研究

分析了Ag-Pd厚膜电阻的烧成过程及其形成的微观结构，建立Ag-Pd厚膜电阻的导电模型；用数学式表述了接触压力和接触电阻的关系，并分析了影响接触压力的因素，包括各组分的膨胀系数、粒度、体积分数和烧成温度。     

钽掺杂的Liao基厚膜电阻导电相和玻璃相颗粒尺寸效应的研究

本文报道了钽掺杂Ｌｉａｏ基厚膜电阻制备过程中导电相和玻璃相颗粒尺寸效应的实验研究结果，当导电相和玻璃相颗粒尺雨分别达到２５和５０ｎｍ时，电阻阻值和电阻温度系数也随之发生显著变化，并尝试根据厚膜电阻导电机理对其产生的原因进行定性的分析。     

烧结温度对厚膜电阻的影响研究

以钌系R-2200厚膜电阻浆料作为研究对象,探讨了烧结温度、保温时间和升温速率工艺因素对其阻值及电阻温度系数(TCR)的影响。利用导电机理模型和液相烧结模型,说明了烧结工艺对钌系厚膜电阻性能的影响。实验数据与SEM表明:厚膜浆料烧结温度在875℃时,结构均匀且致密性好;烧结温度过低时,结构不稳定,功能相没有形成导电网络;而烧结温度过高时,RuO2晶粒异常长大,导电链断裂,势垒升高。     

钽掺杂的钌基厚膜电阻导电相和玻璃相颗粒尺寸效应的研究

本文报道了钽掺杂钌基厚膜电阻制备过程中导电相和玻璃相颗粒尺寸效应的实验研究结果。当导电相和玻璃相颗粒尺寸分别达到25和50nm时,电阻阻值和电阻温度系数也随之发生显著变化,并尝试根据厚膜电阻导电机理对其产生的原因进行定性的分析。     

LTCC基板厚膜电阻的常温稳定性

目前国内尚缺乏与ＬＴＣＣ相配套的厚膜电阻浆料。实验证明，厚膜电阻浆料的导电相、玻璃相及添加剂等对ＬＴＣＣ基板表面厚膜电阻在常温下的稳定性有一定影响。厚膜电阻浆料的膨胀系数随其导电相、玻璃相及添加剂的组分的变化而变化。当厚膜电阻浆料的热膨胀系数与ＬＴＣＣ基板的热膨胀系数之差异大到一定程度时，厚膜电阻在常温下的稳定性就会受到影响。Ｘ射线衍射图谱说明，厚膜电阻与ＬＴＣＣ基板之间生成的方石英相会降低厚膜电阻在常温下的稳定性。     

低温共烧陶瓷表面共烧电阻浆料制备的研究

研究了导电相和玻璃相对共烧厚膜电阻表面状况和稳定性的影响,结果表明：当厚膜电阻中玻璃相软化点接近或低于基板中玻璃相的软化点时,共烧厚膜电阻与基板保持良好的工艺匹配;当厚膜电阻的热膨胀系数接近基板的热膨胀系数时,电阻具有较好的常温、高温等稳定性,X射线衍射分析表明,厚膜电阻与基板之间的不良反应降代电阻的稳定性。     

厚膜电阻浆料的研究现状与发展趋势

针对厚膜电阻浆料的研究现状,探讨厚膜电阻浆料中功能相的种类和粒度,玻璃相、有机载体的成分及含量等因素对厚膜电阻浆料的印刷性能和电性能的影响,简述了添加剂的种类对厚膜电阻的电导率等电性能的影响。因此,厚膜电阻浆料的性能参数是各因素相互作用的结果,通过改变各组分的成分、含量等,获得高性能厚膜电阻浆料配方。     

钌系玻璃釉电位器电阻浆料设计原理及研制

本文作者在深入研究厚膜钌系电阻浆料基础上获得经验和原理，结合厚膜钌系电阻浆料的导电模型和微观结构，提出了玻璃釉电位器电阻浆料的设计原理和电阻表面状态一玻璃相半球模型，通过获得玻璃相表面半球状态，能使电阻表面和铜触点之间的张力与摩擦力匹配，从而本质上改变了电位器特征参数CRV值。通过试验证明在这种状态下，电阻值在50Ω/□、100Ω/□、1kΩ/□、10kΩ/□、100kΩ/□、1MΩ/□都获得了良好的CRV值，在非电阻表面玻璃相半球状态下，电阻CRV值迅速增大。     

一种新型BaPbO3厚膜电阻的研究

对具有金属导电性能的BaPbO3的合成进行阐述，确定合成最低电阻率的摩尔配比。以方阻和电阻温度系数为特征参数对BaPbO3厚膜电阻性能进行分析。通过掺银的方法改善厚膜电阻电阻温度系数负值偏大的状况。并提及一个可能的导电模型解释本文中的实验结果。     

钌基厚膜应变电阻力敏模型的初始讨论

通过分析钌基厚膜应变电阻的隧道势垒模型,提出力敏模型。用Bi2O3和RuO2合成Bi2Ru2O3并进行试验,发现应变系数随导电相粒径的增大而增大。用力敏模型解释了这一现象,并解释了其他力敏现象,诸如应变系数随势垒高度的增大而增大。     

Piezoresistive Materials from Directed Shear‐Induced Assembly of Graphite Nanosheets in Polyethylene

A three‐dimensional conductive nanocomposite with an ordered conductive network and low percolation threshold has been successfully prepared by blending graphite nanosheets (GNs) with polyethylene on a two‐roll mill. The conductive nanosheets orient intensively in the composite, leading to highly anisotropic properties. The nanocomposite with the fraction of conductive nanosheets closest to the percolation threshold possesses a sharp positive pressure coefficient of resistivity, in which the abrupt transition can be attributed to compressive‐stress‐induced deformation of the conductive network. Such piezoresistive effects depend strongly on filler morphology, filler spatial arrangement, and filler concentration.     

烧结过程中毛细作用对钌基厚膜应变电阻的影响

通过应用毛细作用的基本公式得到钌基厚膜应变电阻烧结阶段的模型。用Bi2O3和RuO2合成Bi2Ru2O7并进行试验,发现方阻随烧结时间和导电相粒径的增大而增大。用该模型解释了该现象,同时解释了导电相不同的体系,应尽导电相含量一样,但方阻不同,以及方阻随玻璃粘度增大而减小。     

An advanced laser application for controlling of electric resistivity of thick film resistors

When electric resistivity of Thick Film Resistor (TFR) is adjusted to the desired value, laser beam is irradiated onto the resistor material so that a part of the resistor material is instantaneously vaporized and cut away. This conventional laser trimming method to adjust the resistivity of TFRs is an indispensable technique for manufacturing elec-tronic devices such as hybrid ICs. A peculiar phenomena was revealed by us, that is, when specially selected pulse laser beams were irradiated to TFR, the TFR was surface modified without cutting grooves, and then resistivity of the TFR was decreased. We completed the advanced laser process to apply this peculiar phenomena. 8 By comparing with conventional trimming processes, we can show prominent features of the advanced process, for example, resistivity of fine size TFR (300 micrometers-width and under) can be easily controlled. The decrease in resistivity of the TFR is considered to result from the decrease in specific resistivity of glass in the TFR. Because it is considered that the glass in the TFR is heavily doped with ruthenium impurities during the surface modification due to results of morphology observations and x-ray diffraction analysis. We have applied this advanced laser process to fine size TFR (300 micrometers-width), and developed high density hybrid ICs.     

Electrically Conductive Metal Polymer Nanocomposites for Electronics Applications

An electrically conductive nanocomposite composed of thermoplastic elastomer and nanosized silver particles was developed. Nanosized silver particles were produced by the liquid flame spraying method. Nanocomposites were produced employing a batch mixing process in the melt state. The percolation curve and the minimum resistivity as a function of silver content were defined. A plasticized styrene block-copolymer was used as the matrix polymer. The results showed that the agglomeration of the silver particles has a major influence on the percolation threshold and the resistivity of the compound. With slightly agglomerated silver particles a percolation threshold with a silver content of 13–16 vol.% was achieved. The corresponding resistivity was 2.0 × 10⁻¹ Ω cm. With heavily agglomerated particles the resistivity is high (2.9 × 10³ Ω cm), even with a silver content of 20 vol.%. With a low primary silver particle size (under 100 nm), the resistivity of the compound was high (5.6 × 10⁵ Ω cm).     

The characterization of electrically conductive silver ink patterns on flexible substrates

Electrically conductive silver ink patterns were produced by the screen printing method. Paper, fabrics and plastics were used as the substrate materials. The electrical properties of the samples were characterized by sheet resistance measurement as a function of curing temperature and curing time. The mechanical properties of the samples were characterized by cross hatch adhesion test, bending test and tensile test. Depending on the process parameters and materials, the sheet resistance of the printed conductive patterns varied between 0.04 Ω/□ and 0.13 Ω/□. The curing temperature appeared to have a significant effect on the sheet resistance. In all cases sheet resistance decreased as a function of curing temperature. Adhesion between the substrates and the conductive patterns appeared to be good. The result of the bending test indicated that the resistivity of the silver ink patterns increased as a function of the bending cycle process. The results of the tensile and electrical tests showed that with the screen printing method it is possible to produce highly stretchable electrically conductive patterns for practical applications.     

Large-Area Smooth Conductive Films Enabled by Scalable Slot-Die Coating of Ti3C2Tx MXene Aqueous Inks

Large-area flexible transparent conductive electrodes (TCEs) featuring excellent optoelectronic properties (low sheet resistance, R_s, at high transparency, T) are vital for integration in transparent wearable electronics (i.e., antennas, sensors, supercapacitors, etc.). Solution processing (i.e., printing and coating) of conductive inks yields highly uniform TCEs at low cost, holding great promise for commercially manufacturing of transparent electronics. However, to formulate such conductive inks as well as to realize continuous conductive films in the absence of percolation issue are quite challenging. Herein, the scalable slot-die coating of Ti₃C₂T_x MXene aqueous inks is reported for the first time to yield large-area uniform TCEs with outstanding optoelectronic performance, that is, average DC conductivity of 13 000 ± 500 S cm⁻¹. The conductive MXene nanosheets are forced to orientate horizontally as the inks are passing through the moving slot, leading to the rapid manufacturing of highly aligned MXene TCEs without notorious percolation problems. Moreover, through tuning the ink formulations, such conductive MXene films can be easily adjusted from transparent to opaque as required, demonstrating very low surface roughness and even mirror effects. These high-quality, slot-die-coated MXene TCEs also demonstrate excellent electrochemical charge storage properties when assembled into supercapacitors.     

Piezoresistive Behavior Study on Finger‐Sensing Silicone Rubber/Graphite Nanosheet Nanocomposites

A novel finger‐sensing nanocomposite with remarkable and reversible piezoresistivity is successfully fabricated by dispersing homogeneously conductive graphite nanosheets (GNs) in a silicone rubber (SR) matrix. Because of the high aspect ratio of the graphite nanosheets, the nanocomposite displays a very low percolation threshold. The SR/GN nanocomposite with a volume fraction of conductive nanosheets closest to that for the percolation threshold presents a sharp positive‐pressure coefficient effect of the resistivity under very low pressure, namely, in the finger‐pressure range (0.3–0.7 MPa), whereby the abrupt transition could be attributed to compressive‐stress‐induced deformation of the conducting network. The super‐sensitive piezoresistive behavior of the nanocomposite is accounted for by an extension of the tunneling conduction theory which provides a good approximation to the piezoresistive effect.     

Study on thick-film PTC thermistor fabricated by micro-pen direct writing

Micro-pen direct-write technique has been used to fabricate thick-film PTC thermistor. Thick-film PTC thermistors were fired at 700, 750, 800, 850 and 900 °C. The microstructure and the development of the conductive phase were investigated by optical microscope, scanning electron microscopy and X-ray powder-diffraction analysis. Sheet resistivities and temperature coefficients of resistivity were measured as a function of firing temperature. The conductive phase of the PTC thermistor is based on a mixture of RuO₂, CuO and ruthenate. Pb₂Ru₂O_6.5 decomposes and the cubic-like CuO particle grows up to spinel-like particle during firing at temperature over 750 °C, while the sheet resistivities decrease from high values to a lowest values.     

多层布线介质表面用中高阻电阻浆料的研制

研究了导电相、玻璃相和添加剂对多层布线表面电阻的方阻、温度系数和稳定性的影响，分析了介质层与电阻层之间的相互作用而导致电阻阻值变化的机理。结果表明，选择与介质层相匹配的钌酸铅导电相和铅硅铝玻璃相做功能相，可制得性能良好的电阻浆料。添加剂对提高电阻性能有很大影响。