不同方法合成掺杂ZnO粉体制备ZnO压敏电阻

分别采用低温固相化学法和共沉淀法合成掺杂ZnO粉体,并用这两种粉体在不同温度下烧结制备了ZnO压敏电阻。借助XRD、SEM、TEM、BET等检测手段对粉体产物的性能进行了表征,采用XRD、SEM等手段对ZnO压敏陶瓷的物相、结构进行了分析,并对两种方法制备的粉体及压敏电阻的性能进行了比较研究。结果表明:采用低温固相化学法合成的粉体平均粒径为23.95 nm,用其制备ZnO压敏电阻的最佳烧结温度是1 080℃,其电位梯度为791.64 V/mm,非线性系数是24.36;采用共沉淀法合成的粉体平均粒径为188 nm,用其制备ZnO压敏电阻的最佳烧结温度是1 130℃,其电位梯度为330.99 V/mm、非线性系数是19.70,低温固相化学法制备的ZnO压敏电阻性能优于共沉淀法制备的ZnO压敏电阻。     

纳米Bi_2O_3掺杂对ZnO压敏电阻片电学性能的影响

为获得电学性能优异、生产成本低的ZnO压敏电阻片,本文采用传统陶瓷烧结技术制备ZnO压敏电阻片,研究不同含量纳米Bi_2O_3掺杂对ZnO压敏电阻片的电位梯度、漏电流、非线性系数等电性能的影响。采用压敏电阻直流参数仪对ZnO压敏电阻片的电学性能进行表征。实验结果表明,随着纳米Bi_2O_3含量的增加,ZnO压敏电阻片的电位梯度先升高后降低,漏电流变化不显著,非线性系数先增大后减小。当掺杂纳米Bi_2O_3摩尔分数为0.80%时,ZnO压敏电阻片的电学性能最佳。     

烧结温度对锌硼玻璃掺杂氧化锌压敏陶瓷的影响

研究了不同烧结温度情况下,用固相法制备掺杂锌硼玻璃料ZnO压敏陶瓷,使用CJ1001型压敏电阻直流参数仪测量各样品的电位梯度E_(1 mA),漏电流IL和非线性系数α。结果表明,利用传统陶瓷制备工艺制备得到的锌硼玻璃料掺杂的氧化锌压敏陶瓷样品,以烧结温度1050℃保温时间为2 h所得到样品的电学性能最佳:电位梯度为566 V/mm;非线性系数为115;漏电流为2.6μΑ。     

自蔓延燃烧法合成ZnO粉体及其压敏电阻的制备

以硝酸锌、尿素以及其它添加剂为原料,通过自蔓延燃烧法一次性合成了ZnO压敏电阻用掺杂纳米粉体.用X射线衍射、扫描电镜、比表面测试、激光粒度分析等手段对所制备粉体的性能进行了表征.研究了反应物质量比对粉体性能的影响,以及煅烧温度对ZnO压敏电阻电性能的影响,并对自蔓延燃烧合成反应进行了初步探讨.结果表明:在点火温度为600℃,尿素/金属离子盐质量比为1∶1时,所制备的掺杂纳米ZnO粉体的综合性能最好.用此粉体制备的ZnO压敏电阻的电性能最佳,电位梯度为745.27V/mm,非线性系数为56.53,漏电流为6μA.     

微波直接氧化法制备超细ZnO粉

根据微波加热特点,用一种微波新工艺直接将锌粒氧化制备ZnO粉末.研究表明,以工业锌粒为反应原料,碳化硅泡沫陶瓷作为承载板,微波快速加热制备ZnO粉末,氧化完全,可得到棒槌形状的氧化锌晶体,与传统电炉合成比较,反应温度低,保温时间短,晶粒细小均匀.     

高压ZnO压敏电阻陶瓷材料研究进展

综述了高压氧化锌压敏电阻的导电原理及制备工艺,从超细粉体的制备、稀土添加剂、烧结工艺等方面重点分析了目前该材料的制备方法。并指出高压氧化锌压敏电阻材料今后应从以下几方面进行重点研究:①加强大电流区的失效模式与显微结构之间的相关理论研究;②稳定纳米ZnO粉体,特别是掺杂如Bi_2O_3等其他成分纳米复合粉末的制备研究;③复合稀土氧化物对氧化锌电阻片的微观和电学性能的影响研究,对掺杂量的控制及作用机理将是未来研究的重点;④开发和优化如微波烧结等新的烧结工艺。     

室温固相合成掺杂ZnO纳米粉体制备ZnO压敏电阻

以金属离子盐和草酸为原料,采用室温固相化学反应合成掺杂ZnO前驱物,根据DSC-TG分析结果,将其在450℃热分解2 h,得到掺杂ZnO粉体,并用此粉体制备了片式ZnO压敏电阻。借助XRD、TEM、BET等检测手段对粉体产物的物相、形貌、粒度等进行了表征。研究了烧结温度对ZnO压敏电阻电性能的影响。结果表明,所制备的粉体为平均粒径24 nm左右、颗粒呈球状、分散性好的纤锌矿结构掺杂ZnO。在1 080℃烧结时,ZnO压敏电阻的综合电性能达到最佳,电位梯度为791.64 V/mm,非线性系数为24.36,漏电流为43μA。     

共沉淀法制备ZnO基纳米复合粉体及高压ZnO压敏电阻的电性能

以金属离子盐为原料,氨水、乙醇胺为沉淀剂,十二烷基苯磺酸钠、聚乙二醇2000为表面改性剂,采用共沉淀法制备ZnO基纳米复合粉体。以共沉淀法最佳工艺所得粉体制备高压ZnO压敏电阻。采用热重–差示扫描量热分析、X射线衍射、扫描电子显微镜、激光粒径分析对ZnO基复合前驱体及ZnO基纳米复合粉体进行表征,探讨了沉淀剂种类、溶液pH值、Zn2＋起始浓度和表面改性剂对粉体粒度的影响。结果表明：以氨水为沉淀剂、溶液体系pH值为6.0、Zn2＋浓度为1.0mol/L、聚乙二醇2000为表面改性剂时可制备出粒径分布窄、平均粒径为89nm的ZnO基复合粉体。用该粉体制备的高压ZnO压敏电阻的平均电位梯度为543V/mm,非线性系数为29.3,漏电流为49μA。通过共沉淀工艺,可制备出电性能优良的高压ZnO压敏电阻。     

ZnO压敏电阻及其片式化技术

ZnO压敏电阻由于具有独特的非线性Ⅰ-Ⅴ特性而在电子电路中得到了广泛应用。随着电子产品向着小型化、高集成化和数字化方向发展,片式ZnO压敏电阻(ZnO MLVs)应用日益广泛。基于此,本文结合作者对ZnO压敏陶瓷还原-再氧化工艺及贱金属内电极的研究,介绍了目前ZnO MLVs的主要材料及工艺研究进展,并对片式ZnO压敏电阻的发展趋势提出了一孔之见。     

压敏电阻复合粉体用ZnO的制备方法简介

本文综述了工业级氧化锌精制为电子陶瓷用氧化锌的方法及共用化学合成制备氧化锌压敏电阻多元复合粉体的研究进展。     

水基流延片式ZnO压敏电阻器低温共烧工艺及其性能

用环境扫描电子显微镜（ESEM）、X射线衍射（XRD）和X射线能谱（EDXS）等研究了水基流延片式ZnO压敏电阻器的低温共烧工艺及其对微观结构和电学性能的影响规律。ESEM分析结果表明：当等静压压力为60 MPa时,Ag电极与流延膜生坯界面结合紧密,Ag电极分布连续,900℃共烧时,未出现开裂、分层,两者收缩率接近。EDXS和XRD分析结果表明：900℃共烧时,Ag在片式压敏电阻器中以单质形式存在,流延膜与Ag电极化学兼容性良好,且在共烧界面处未发现有明显的Ag离子扩散。该流延膜可以与Ag电极在900℃时实现低温共烧,用此制备的片式ZnO压敏电阻器具有良好的压敏性能：压敏电压V1mA=6.1 V,非线性系数α=28.1,漏电流IL=0.15μA。     

Electrical characterization of ZnO multilayer varistors on the nanometre scale with conductive atomic force microscopy

The conductivity of ZnO–varistor ceramics has been analyzed with conductive atomic force microscopy (C-AFM) under atmospheric conditions by measuring the current at different voltages and positions in zinc oxide-based multilayer varistors (MLVs). It is possible to detect individual ZnO grains on the polished sample surface in the AFM topography mode as well as in the two-dimensional current images. Additionally local current–voltage (IV) curves revealed details of the electrical behaviour of the material. To correlate the laterally resolved current image with grain orientations, electron backscattering diffraction (EBSD) has been performed. Beside the well-known varistor behaviour specific influence of the local microstructure has been found.     

High-current measurement of the grain resistivity in zinc oxide varistor ceramics

A new pulse technique for grain resistivity measurement in varistor ceramics is suggested. Such technique allows obtaining more precise value of the grain resistivity due to the use of the concept of differential electrical resistance. This technique can be used in the current density range where the overheating of varistor sample is insignificant. The technique was verified using commercial ZnO varistors. Grain resistivities of 0.60±0.02 Ω cm at 293 K and of 3.40±0.13 Ω cm at 77 K were obtained. This result indicates the negative temperature coefficient of grain resistance in ZnO varistor in the range (77–293) K. The contribution of the grain boundaries to the current–voltage characteristic of ZnO varistor is estimated on the basis of the measured grain resistivity and the current–voltage data. It is shown that the electrical conduction in ZnO varistor is controlled by grains if the current density exceeds approximately 1000 А сm⁻².     

添加Nd2O3对氧化锌压敏阀片电性能与显微组织的影响

研究了微量Nd2O3添加剂对氧化锌压敏阀片的压敏电位梯度、漏电流和压比的影响,并对其显微组织进行了分析研究,从理论上探讨了Nd2O3对氧化锌压敏阀片电性能与组织的作用机理。研究结果表明:当Nd2O3的摩尔分数为0.04％时,氧化锌压敏阀片的压敏电位梯度最高,漏电流最小,压比最低,具有优良的综合电性能。其原因是Nd2O3加入到氧化锌压敏阀片中,使晶粒尺寸减小所致。     

A Novel Test Method for Ultrafast Pulse Response Characteristics of ZnO Varistor Ceramics

A ZnO varistors in series connected with a semi‐insulating GaAs photoconductive switches (SI‐GaAs PCSS's), a test method for ultrafast pulse response characteristics of ZnO varistor ceramics with DC bias was presented for the first time. The DC voltage distribution of the PCSS's and the varistors was measured in a dark state and the pulse response characteristics of the ZnO varistor ceramics was examined by a nanosecond laser pulse illuminating the PCSS's. The results indicate that the electric pulse output from the varistors includes capacitive current and conduction current and there is a time delay between their peaks. It is revealed that ZnO varistors has a nonlinear conductivity for the nanosecond electric impulse excitation and the barrier capacitance decay constant of the ceramics sample is 105 ns, which is explained through the analysis of examining the material structure and the conductive mechanisms.     

Voltage-Current Characteristics of a Simple Zinc Oxide Varistor Containing Magnesia

This paper examines the effect of MgO addition on the structural and electrical characteristics of a ZnO varistor composition with few dopants. MgO acts as a grain-growth inhibitor. The electrical performances of the obtained varistors are improved.     

Sandwich-structured ZnO-MnO2-ZnO thin film varistors prepared via magnetron sputtering

ZnO varistors are widely used to protect electronic circuits form transient voltages. However, it is difficult to prepare varistors with voltage less than 10 V using ZnO ceramics. Here we prepared a ZnO-MnO₂-ZnO (ZMZ) sandwich thin film via magnetron sputtering and subsequent annealing at 200-500 °C. With the increase of annealing temperature, the manganese oxide sandwich layer reacts with the upper and lower ZnO layer and becomes thinner. After annealed at 500 °C, because of ZnO grain growth, the upper and lower ZnO layers joined together. The electrical properties of ZMZ films annealed at 400 °C show strong nonlinear I-V characteristics. A ZMZ low voltage thin film varistor with planar boundary potential barrier was obtained whose nonlinear coefficient α and varistor voltage V1 mA are about 30 and 6.0 V, respectively. The stable and excellent nonlinear characteristics make it a promising candidate for overvoltage protection in low operating voltage circuits.     

Design and fabrication of flexible poly(vinyl chloride) dielectric composite reinforced with ZnO microvaristors

Flexible poly(vinyl chloride)/varistor composites were fabricated by solution casting method. High‐field ZnO varistor particles processed from micron‐sized Zn dust is explored as multifunctional filler for PVC composites. Mechanical blending of Zn dust with La₂O₃‐CeO₂ rare earths and varistor forming minor additives followed by sintering at 1250 °C resulted in fine‐grained ZnO varistors. Bulk varistor was subsequently milled to obtain ZnO microvaristor grains. The effect of microvaristor on the UV stability, dielectric, and mechanical properties of the PVC composite was analyzed. The varistor filler in PVC enhanced the microhardness and retained the tensile properties without any significant loss. After UV irradiation PVC/varistor composite shows remarkable mechanical stability retention (95%) compared to pure PVC (75%). Also, microvaristor reinforcement resulted in dielectric constant tunability (? = 2–37) without any drastic change in the dielectric loss (0.02–0.05). Thus, Zn dust‐derived ZnO varistors could be potentially exploited to design functional PVC composites for electronic applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46031.     

掺杂对ZnO压敏陶瓷电性能的影响及其应用

ZnO压敏陶瓷具有优良的电流-电压非线性和冲击能量吸收能力、低漏电流和低成本,广泛用于电力系统和电子线路等领域。介绍了掺杂改性对ZnO压敏陶瓷电性能的影响,最后介绍了ZnO压敏陶瓷的应用。     

Co2O3的理化性能对ZnO压敏陶瓷电性能的影响

本文详细研究了氧化钴的理化性能对ＺｎＯ压敏陶瓷性能的影响。论述了Ｃｏ２Ｏ３的热特性对压敏陶瓷烧成工艺产生的影响及控制措施，从理论上探讨了氧化 中所含杂质Ｆｅ、Ｃｕ，Ｎａ等对ＺｎＯ压敏陶瓷电性能的不利作用。提出了控制的上限，并试制出一种用于氧化锌压敏陶瓷的性能优良的Ｃｏ２Ｏ３粉体。