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1.
随着国家对具有放射性危害的钍资源有计划性的管理,钍的价格不断上升,推动了焊接领域环保钨电极替代钍的发展。对市场上现有替代钍钨的Ce-W,三元稀土W电极(La-Ce-Y)以及美国市场上积极推广的E3电极的焊接性能进行研究,采用钨极氩弧焊(TIG)直流正接(DCSP)的方法研究了几种电极的高温抗烧损性能,尺寸稳定性以及静特性曲线,并对燃弧后电极尖端的表面形貌进行了扫描电镜(SEM)观察,对稀土添加相La2O3,Y2O3,CeO2在电极尖端轴向分布进行了能谱分析(EDX)。对比试验结果发现,在焊接电流200 A工作5 h后,E3和WX电极的烧损量明显小于Th-W,Ce-W电极,且质量损失随时间呈近似的线性关系,尺寸稳定性好。从金相组织可以看出Th-W,Ce-W电极再结晶晶粒粗大,E3和WX电极的再结晶晶粒小,再结晶程度较弱,从侧面说明E3和WX电极工作温度较低,电子发射能力强。几种稀土氧化物的行为揭示了电极性能差异的本质原因,多元电极中,CeO2的扩散速率最快,使得其在小电流焊接和起弧过程中作用明显。Y2O3和La2O3热稳定性好,只有在较高温度时其扩散速率才明显增加,因此它们在大电流长时间焊接时作用突出。由于几种元素的协同作用,降低了电极表面的逸出功,并使得电子发射过程稳定。因此,三元稀土钨电极(WX)具有优异的焊接性能。  相似文献   

2.
在钨电极中添加稀土元素的优化研究   总被引:6,自引:0,他引:6  
在保证材料能顺利进行塑性加工的前提下,为了提高钨电极的热电子发射能力,对几种稀土元素对钨电极材料的影响情况进行了研究,结果表明:添加总量为钨基体质量2%的稀土氧化物,且Y2O3:(La2O3 CeO2)比例为3:2的钨电极,其综合性能最佳。  相似文献   

3.
介绍了笔者最近几年关于稀土钨、钼材料的研究工作.研究结果表明,在钨和钼中掺入不同稀土氧化物种类和含量,可制成系列稀土钨电极材料,其综合焊接性能超过先行的钍钨电极材料,克服了钍钨电极的放射性污染.所研制的稀土钼材料,具有工作温度低、韧性好和无放射性污染,由于发射稳定性的突破,使稀土钼阴极材料达到实用化.  相似文献   

4.
稀土钨、钼电极电子发射性能研究与应用开发   总被引:4,自引:1,他引:3  
介绍了等者最近几年关于稀土钨、钼材料的研究工作。研究结果表明,在钨和钼中掺入不同稀土氧化物种类和含量,可制成系列稀土钨电极材料,其综合焊接性能超过先行的钍钨电极材料,克服了钍钨电极的放射性污染。所研制的稀土钼材料,具有工作温度低、韧性好的无放射性污染,由于发射稳定性的突破,使稀土钼阴极材料达到实用化。  相似文献   

5.
稀土钨电极在金卤灯的应用研究   总被引:1,自引:0,他引:1  
利用液-固混合法制备的含稀土氧化物的钨基合金材料,经加工制成小功率金卤灯电极,并组装成70W的金卤灯整灯。对不同电极材质的金卤灯测定发光特性,并进行分析对比,钨镝和钨镝钇合金电极的金卤灯的启动、防溅性能和抗腐蚀性能可达到钨钍合金电极的水平。  相似文献   

6.
稀土钨电极材料的研究   总被引:2,自引:1,他引:2  
钍钨电极具有放射性,其生产和使用过程中污染环境危害人类身体健康,因此需要新型电极产品加以替代,稀土钨电极焊接性能优良一直作为钍钨电极的替代产品而倍受关注,回顾课题组在稀土钨电极的研究历程,经过对单元稀土钨电极、二元复合稀土钨电极、三元复合稀土钨电极的研究,目前通过与北京钨钼材料厂合作,共同突破了多元复合稀土钨电极的工业化生产技术,实现了该类电极批量生产。  相似文献   

7.
<正> —.前言 钨极惰性气体保护焊(TIG)对高台金化材料的焊接工艺显得日益重要。多年来,人们已在非熔化电极中掺入了低放射性的氧化钍(ThO_2)。但ThO_2对环境卫生的可能危害已促使人们不断探索能在钨电板中掺入某些具有低逸出功的新型添加剂。尤其是稀土元  相似文献   

8.
钨电极加工变形组织研究   总被引:1,自引:0,他引:1  
对钍钨电极、单元稀土钨电极和多元稀土钨电极的3个典型状态(再结晶退火态、202旋锻、成品)的显微组织进行观察,探讨钨电极在加工过程中组织演变规律。结果表明:在加工过程中,三种电极显微组织均随加工程度的增加逐步纤维化,但第二相的行为却各有特点。钍钨电极第二相颗粒细小,变形能力较差;单元稀土钨电极的第二相颗粒略大,变形能力较强;多元稀土钨电极第二相颗粒最大,变形能力差。在现有的工艺条件下,钍钨电极和单元稀土钨电极的加工性能优于多元稀土钨电极,第二相尺寸大小和变形能力对钨电极的加工性能具有重要影响。  相似文献   

9.
复合稀土钨电极研究   总被引:4,自引:1,他引:3  
测试了几种稀土钨电极的焊接性能,并对其组织结构进行了分析,深入探讨了稀土在不同电极中的作用机理。发现高温下稀土相形状将发生改变,毛细管现象只在电极开始工作时存在。由于传输速率和蒸发速率不同,铈钨电极头部出现贫稀土,侧面形成环状富集;1:2:1镧铈钇电极侧表面富稀土;1:1:3镧铈钇电极表面出现融熔;稀土通过融熔的钨传输到表面;从而保持电极的形状不变和电弧的稳定。  相似文献   

10.
通过对单元稀土钨合金材料和多元稀土钨合金材料的研究及稀土钨电极的制备,并组装成不同功率的照明金卤灯和汽车金卤灯,测定其发光性能,经对比分析,可知用稀土钨电极的灯的主要性能达到钍钨电极灯的水平,能部分取代传统的有放射性污染的钍钨电极,实现环保条件和材料性能的双替代。  相似文献   

11.
Effect of rare earth metal oxide additions to tungsten electrodes   总被引:7,自引:0,他引:7  
A comparative study has been made on the operating characteristics of gas-tungsten arc (GTA) welding for several types of electrodes. The work was carried out with a pure tungsten electrode and tungsten electrodes activated with a small quantity of the rare earth metal oxides, La2O3, Y2O3, CeO2, and with ZrO2, ThO2, and MgO. Their behaviors during arcing were analyzed and compared from the points of view of arc starting characteristics, electrode consumption, change in shape due to long-term operation, and incompleteness of insert gas shielding and electrode temperature. The results indicated that W-La2O3 electrodes have superior characteristics among those tested. Metallographic studies of the electrodes indicate that the superiority of operating characteristics strongly depends on the behavior of the rare earth metal oxides during arc burning. It is observed that the rare earth metal oxides form tungstate or oxytungstate during arc burning. These newly formed compounds have low melting points and migrate from the low temperature zones to the high temperature zones throughout the electrode tip, while ThO2 reacts with tungsten, forming pure Th. Also, the investigation demonstrates good stability of La2O3 during arc burning compared with the other oxides. Particular attention was also paid to the electrode temperature measurement and the important phenomena concerning the emissivity of a particular surface as one of the thermal properties. The investigation reveals the effects of temperature and oxide distribution on the spectral emissivity of the electrode in addition to the main different effect of oxides added to tungsten. Observations of the cathode tip microstructure during and after arc burning were made, and important phenomena concerning the formation of a tungsten “rim” at the periphery of the cathode area, which governs the durability of the electrode and the stability of the arc, are discussed theoretically and experimentally based on the temperature measurement of the tip and the oxidation of tungsten. ALBER A. SADEK, formerly with the Welding Research Institute, Osaka University  相似文献   

12.
The doping effects of rare earth oxides Ho2O3 and Er2O3 on dielectric properties of BaTiO3-based ceramics were studied. After adding rare earth elements, grain growth in this system was inhibited and the grain size was reduced evidently which realized the fine-grained effect. In this system, the trivalent oxides Ho2O3 and Er2O3 were added to BaTiO3 ceramics. The rare earth oxides do not enter into inner lattice totally to replace A or B sites.Some of additives can improve dielectric strength by forming nonferroelectric phases, and the rest maintained at grain boundaries controls overgrowth of grains. The dielectric constant at room temperature is increased up to 3000 and the curve of TCC becomes flat.Meanwhile, the dielectric strength Eb becomes higher.  相似文献   

13.
采用喷射沉积和内氧化法制备出Al2O3La2O3Y2O3/Cu复合材料,研究该材料在直流20 V/20 A的工作条件下触点的电弧侵蚀特性,并与Al2O3/Cu材料进行了对比分析.利用电子天平、扫描电镜等方法分析电弧侵蚀后触点的质量变化和表面微观结构.结果表明,通过添加Y2O3、La2O3稀土氧化物颗粒,可有效降低触头材料的材料转移量.Al2O3La2O3Y2O3/Cu材料的抗熔焊性和抗烧损性优于Al2O3/Cu材料的性能.在直流阻性负载条件下Al2O3La2O3Y2O3/Cu阳极触头表面形成凹坑,阴极触头表面形成凸起,触点表面显示出浆糊状凝固物和喷发坑等电弧侵蚀形貌特征.  相似文献   

14.
稀土氧化物可作为稳定剂、烧结助剂、掺杂改性剂加入到ZrO2陶瓷材料中,能极大地提高和改善陶瓷材料的强度、韧性,降低其烧结温度,减少生产成本.文中简要综述了稀土氧化物ZrO2陶瓷材料的制备及应用研究状况,包括Y2O3复合ZrO2陶瓷粉体、富铈稀土氧化物复合ZrO2陶瓷粉末、Nd2O3复合ZrO2陶瓷材料、Pr2O3\Pr6O11复合ZrO2陶瓷、La2O3复合ZrO2陶瓷、Yb2O3复合ZrO2陶瓷、Sm2O3复合ZrO2陶瓷材料及氧化锆中掺杂多种稀土氧化物陶瓷粉体的制备和应用,分析讨论了一些需要解决的问题,并展望了稀土复合ZrO2陶瓷制备技术及未来研究发展趋势.  相似文献   

15.
Effects of flaky rare earth oxide additives including Er2O3,Tm2O3,and Yb2O3,Lu2O3 on high temperature and high rate discharge performance of nickel electrodes were investigated.The discharge efficiency at 0.2C reached 96% at 60 oC for electrodes with 1 at.% flaky rare earth oxides.The high rate discharge performance for electrodes with flaky rare earth oxides were improved significantly,for example,discharge efficiency at 5C improved from 50% to 70%.The results showed that the end charging potential of the ...  相似文献   

16.
Adding rare earth oxide CeO2 with variable valences to La2O3 formed a mixture of rare earth oxides. By means of dipping CeO2, La2O3 and their mixture, whose carriers were all γ-Al2O3, were used as the catalyst for the reduction of SO2 by CO. The activation process of this catalyst and the impact of temperature and reactant concentration on the activation process were investigated. Using X-ray diffraction, the structure characteristics of catalyst before and after reaction were analyzed to reveal the change of phase structure. The result shows that the rare earth oxide mixtures composing of CeO2 and La2O3, as the catalyst for the reduction of SO2 by CO, diminish activation temperature 50~100℃ less and have higher activity than a single oxide CeO2 or La2O3. The reason possibl is that La2O3 goes into in the lattice of CeO2 to form solid phase complex CeO2-La2O3 and increases the capability of CeO2-La2O3/γ-Al2O3 catalyst to store oxygen, which supplies the redox of CeO2 reaction with a better condition. At the same time, elemental sulfur formed in the redox reaction impels La203 to be transformed to activation phase La2O2S in a lower temperature, which can be explained with the synergism between redox reaction and COS intermediate mechanism reaction.  相似文献   

17.
多元复合稀土钨电极是用于取代有放射性危害的钍钨电极的新一代绿色环保产品,笔者介绍了在深入的机理研究和性能测试基础上,设计筛选出了多元复合稀土钨电极的最佳成分,并对该成分的钨电极进行了产业化技术研究和工业生产考察,取得了圆满的结果。  相似文献   

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