BaO对高温压敏电阻器漏电流的影响

在ＺｎＯ高温压敏电阻原料中加入不同比例的ＢａＯ，研究其对高温压敏电阻漏电流和高温下长期工作的稳定性的影响。发现ＢａＯ含量较高时，不但可以降低ＺｎＯ压敏电阻常温下的漏电流，而且可以增加其在高温下长期工作的稳定性。     

用湿化学法制备电子材料用ZnO粉末

本文研究用湿化学法——ＮＨ＿３法改性ＺｎＯ粉末使之用于电子材料．用ｘ－ｒａｙ衍射分析和ＳＥＭ分析方法确定了焙烧温度、球磨时间等主要工艺参数；用ＳＥＭ分析、ＢＥＴ分析、粒度与粒度分布分析方法研究了改性前后ＺｎＯ粉末的赋存状态．压敏电阻验证试验结果表明，改性后的ＺｎＯ粉末可以制备出小电流性能很好的ＺｎＯ压敏电阻．     

ZnO-玻璃系压敏电阻材料研究

研究了不同种类的玻璃料对ＺｎＯ－玻璃系压敏电阻电性能的影响．实验表明加入Ｇ３ 玻璃料制得的样品具有较好的电性能，并有很高的工作稳定性．还研究了ＺｎＯ－玻璃系压敏电阻的微观结构和介电性能     

少量异组分对贝利特性能的影响

本文采用正交试验法，探讨了ＢａＯ、ＺｎＯ、Ｐ２Ｏ５、ＴｉＯ２、Ｒ２Ｏ（Ｋ２Ｏ＋Ｎａ２Ｏ）等少量异组分对贝利特性能的影响及其影响的显著性大小．结果发现：ＺｎＯ对贝利特净浆强度影响最显著，ＢａＯ、Ｐ２Ｏ５的作用次之，而ＴｉＯ２、Ｒ２Ｏ在本实验条件下对贝利特净浆强度无明显影响．ＺｎＯ的掺入将显著降低贝利特净浆强度，而适量掺入ＢａＯ、Ｐ２Ｏ５则有利于提高贝利特净浆强度，但当ＢａＯ掺量过多时，将导致贝利特净浆后期强度降低．     

用湿化学法制备电子材料用ZnO粉未

本文研究用湿化学法－ＮＨ３法改性ＺｎＯ粉末使之用于电子材料。用Ｘ－ｒａｙ衍射分析和ＳＥＭ分析方法确定了焙烧温度，球磨时间等主要工艺参数；用ＳＥＭ分析，ＢＥＴ分析，粒度与粒度分布分析方法研究了改性前后ＺｎＯ粉末的赋存状态。压敏电阻验证试验结果表明，改性后的ＺｎＯ粉末可以制备出小电流性能很好的ＺｎＯ压敏电阻。     

臭氧发生器用（Sr,Ca）TiO3陶瓷电极材料的研制

研究了掺杂成分ＢａＴｉＯ３,ＣａＳｉＴｉＯ５,ＴｉＯ２,ＺｎＯ,Ｂｉ２Ｏ３对臭氧发生器用（Ｓｒ,Ｃａ）ＴｉＯ３陶瓷电极材料的介电常数、正切损耗、击穿电压、电阻率等电性能的影响．结果表明,Ｂｉ２Ｏ３的影响最大．最适合的掺杂配方是：Ｂｉ２Ｏ３１．４０％,ＴｉＯ２０．３０％,ＣａＳｉＴｉＯ５０．３１％,ＢａＴｉＯ３０．５０％和ＺｎＯ０．５２％．     

ZnO—玻璃系压敏电阻材料研究

研究了不同种类的玻璃料对ＺｎＯ－玻璃系压敏电压性能的影响，实验表明加入Ｇ３玻璃制得的样品具有较好的电性能，并有很高的工作稳定性，还研究了ＺｎＯ－玻璃系压敏电阻的微观结构和介电性能。     

ZnO压敏陶瓷热处理实验的研究

ＺｎＯ压敏陶瓷在工作电压长期作用下，会产生电流蠕变现象，使Ｓｃｈｏｔｋｙ势垒不稳定．用正电子湮没技术（ＰＡＴ）证实：ＺｎＯ在适当温度下的氧化热处理，使氧离子Ｏ－或Ｏ２－吸附于晶界层内并有利于提高ＺｎＯ性能稳定性     

钨系厚膜材料中玻璃相对高温稳定性的影响

钨系导电陶瓷厚膜材料可长期在５００～７００℃下工作，导电厚膜材料的高温稳定性问题与材料中玻璃相的类型及含量有关．通过采取降低玻璃相和其中的ＰｂＢＯ３的含量、提高玻璃相的软化温度、制备玻璃－陶瓷作为厚膜材料的玻璃相及对材料进行热处理等措施可以有效改善材料的高温稳定性．     

BaAl12O19高温热稳定材料制备方法

ＢａＡｌ１２Ｏ１９是一种被用于高温催化燃烧的β－Ａｌ２Ｏ３型材料．在其制备过程中可采用柠檬酸盐无定形前驱体法．它在１３０℃的分解反映出硝酸盐与自由羰基的相互作用；３６０℃的分解对应于柠檬酸盐的氧化；在８００℃时，ＢａＣＯ３分解并生成ＢａＡｌ２Ｏ４．ＢａＡｌ２Ｏ４的产生并没有抑制ＢａＡｌ１２Ｏ１９的形成．形成ＢａＡｌ１２Ｏ１９的另一条途径是γ－Ａｌ２Ｏ３同分散相Ｂａ２＋之间的反应     

Effect of SiO<Subscript>2</Subscript> addition on the microstructure and electrical properties of ZnO-based varistors

The microstructure and electrical properties of ZnO-based varistors with the SiO₂ content in the range of 0–1.00mol% were prepared by a solid reaction route. The varistors were characterized by scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectrometry, inductively coupled plasma-atomic emission spectrometry, and X-ray photoelectron spectroscopy. The results indicate that the average grain size of ZnO decreases with the SiO₂ content increasing. A new second phase (Zn₂SiO₄) and a glass phase (Bi₂SiO₅) are found. Element Si mainly exists in the grain boundary and plays an important role in controlling the Bi₂O₃ vaporization. The electric measurement shows that the incorporation of SiO₂ can significantly improve the nonlinear properties of ZnO-based varistors, and the nonlinear coefficients of the varistors with SiO₂ are in the range of 36.8–69.5. The varistor voltage reaches the maximum value of 463 V/mm and the leakage current reaches the minimum value of 0.11 μA at the SiO₂ content of 0.75mol%.     

高温、高压LDMOS导通电阻的特性

本文提出了高温、高压LDMOS的等效电路,讨论了LDMOS泄漏电流及其本征参数在高温下随温度变化的规律.根据分析,漏pn结的反向泄漏电流决定了LDMOS的高温极限温度,导通电阻与温度的关系为Ron∝((T)/(T1))y(y=1.5～2.5).     

ZnO压敏材料研究进展

氧化锌压敏电阻器具有优良的非线性伏安特性,在稳态工作电压下漏电流很小(能耗低).利用这些特性可制造各种电子器件的过电压保护、电子设备的雷击浪涌保护、负载开关的浪涌吸收等电子保护装置.综述了ZnO压敏材料的导电机理、老化、非线性功能添加剂以及制备工艺等方面的研究进展,指出ZnO压敏电阻器的发展方向为片式叠层化、低压化以及对导电机理的深入研究.     

Fe--36 Ni因瓦合金的热塑性

采用Gleeble-3800热模拟试验机研究Fe-36Ni合金在900~1200℃的热塑性行为,并用FactSage软件、扫描电镜及透射电镜等研究该合金热塑性的影响因素及作用机理.结果表明：合金中主要形成Al2 O3+Ti3 O5+MnS复合夹杂,夹杂物颗粒尺寸集中分布在0.5μm以下.合金热塑性在900~1050℃受晶界滑移及动态再结晶共同影响.晶界上分布的纳米级别(<200 nm)夹杂物有效钉扎晶界,抑制动态再结晶发生的同时减小晶界结合力.微米级别(>200 nm)夹杂物则促进显微裂纹在晶界滑移过程中的形成和扩展,损害合金热塑性.当温度高于1050℃时,较高的变形温度使再结晶驱动力大于钉扎作用力,合金发生动态再结晶,有效提高热塑性.在1100~1200℃区间内,枝晶间裂纹的形成、晶界滑移的加剧及动态再结晶晶粒尺寸增大都降低合金热塑性.     

Enhanced supercurrent density in polycrystalline YBa2Cu3O(7-delta) at 77 K from calcium doping of grain boundaries

With the discovery of high-temperature superconductivity, it seemed that the vision of superconducting power cables operating at the boiling point of liquid nitrogen (77 K) was close to realization. But it was soon found that the critical current density Jc of the supercurrents that can pass through these polycrystalline materials without destroying superconductivity is remarkably small. In many materials, Jc is suppressed at grain boundaries, by phenomena such as interface charging and bending of the electronic band structure. Partial replacement ('doping') of the yttrium in YBa2Cu3O(7-delta) with calcium has been used to increase grain-boundary Jc values substantially, but only at temperatures much lower than 77 K (ref. 9). Here we show that preferentially overdoping the grain boundaries, relative to the grains themselves, yields values of Jc at 77 K that far exceed previously published values. Our results indicate that grain-boundary doping is a viable approach for producing a practical, cost-effective superconducting power cable operating at liquid-nitrogen temperatures.     

汽轮机高温螺栓断裂失效分析

断裂螺栓晶粒粗大,有严重的混晶现象,碳化物及其他夹杂物在晶界呈链状或团状析出,使晶界脆化、晶界结合力下降而产生沿晶裂纹,导致螺栓发生沿晶脆性断裂。另外,螺栓在检修中出现表面损伤或受较大的预紧力也是螺栓断裂的另一原因。通过对某火力发电厂汽轮机高温螺栓失效分析,认为高温螺栓断裂机理以蠕变断裂为主;根据螺栓更换及判废标准,对现行的螺栓监督检验方法的有效性进行分析。     

Electrolyte materials for intermediate-temperature solid oxide fuel cells

Solid oxide fuel cells (SOFCs) directly convert chemical energy that is stored in a wide range of fuels into direct current electricity, with high efficiency and low emissions, via a series of electrochemical reactions at elevated operating temperatures (generally 400–1000 °C). During such an energy conversion process, the properties of electrolyte materials determine the working principle and operating temperature of the SOFC. When considering the cost and stability, lowering the operating temperature is critical, and this has become one of the developing trends in SOFC research. The key point for realizing a reduction in operating temperature is to maintain low ohmic resistance of the electrolyte and low polarization resistance of the electrodes. In practice, the mechanical and chemical stability of the electrolyte is also a big concern. According to their differences in ion conduction mechanisms, there are three main types of electrolyte material available, namely, oxygen ion-conducting, proton-conducting, and dual ion-conducting electrolytes. In this review, we give a comprehensive summary of the recent advances in the development of these three types of electrolyte material for intermediate-temperature SOFCs. Both conductivity and stability are emphasized. In conclusion, the current challenges and future development prospects are discussed.     

单斜相SrAl2Si2O8陶瓷的烧结及其对Sr的固化

Monoclinic SrAl₂Si₂O₈ ceramics for Sr immobilization were prepared by a liquid-phase sintering method. The sintering temperature, mineral phase composition, microstructure, flexural strength, bulk density, and Sr ion leaching characteristics of the SrAl₂Si₂O₈ ceramics were investigated. A crystalline monoclinic SrAl₂Si₂O₈ phase formed through liquid-phase sintering at 1223 K. The introduction of four flux agents (B₂O₃, CaO·2B₂O₃, SrO·2B₂O₃, and BaO·2B₂O₃) to the SrAl₂Si₂O₈ ceramics not only reduced the densification temperature and decreased the volatilization of Sr during high-temperature sintering but also impacted the mechanical properties of the ceramics. Product consistency tests showed that the leaching concentration of Sr ions in the sample with flux agent B₂O₃ was the lowest, whereas that of Sr ions in the sample with flux agent BaO·2B₂O₃ was the highest. These results show that the leaching concentration of Sr ions depends largely on the amorphous phase in the ceramics. Meanwhile, the formation of mineral analog ceramics containing Sr is an important factor to improve Sr immobilization.     

锂离子导体Li6La2BaTa2O12在潮湿空气中的稳定性研究

利用交流阻抗谱研究锂离子导体Li La₂ BaTa₂ O₁₂在空气的稳定性。锂离子导体Li₆ La₂ BaTa₂ O₁₂首先在空气中吸附水气进入晶界,导致该材料晶界电阻变大;随后进入晶界中的水气和Li₆ La₂ BaTa₂ O₁₂材料发生质子和锂离子的离子交换反应,导致了晶格的进一步畸变,表现为晶粒电阻直线增加。因此可通过提高陶瓷材料致密度,抑制水气进入晶界,提高该材料对水气的稳定性,这对该材料在全固态锂离子电池中的应用具有十分重要的意义。