【作者】 沈娇；

【导师】 唐振方；

【作者基本信息】 暨南大学 ， 凝聚态物理， 2010， 硕士

【摘要】 电触头主要负责接通、断开电路及负载电流的任务,由于它的特殊作用,电接触材料的性能直接影响电子产品的可靠性、稳定性、精度和使用寿命。在闭合和断开的过程中触头受到电侵蚀是导致其不能正常工作的主要原因。因此开展抗电侵蚀性能强的电接触材料的研究有重要的意义。本文主要研究机械合金化法制备AgCr触头材料及其性能。首先,分析球磨转速和球磨时间对球磨粉末物相、晶粒大小、微观应变和粉末形貌的影响,主要是用X射线衍射仪和扫描电子显微镜对粉末进行物相及形貌分析。其次,研究球磨转速、球磨时间、球料比和烧结温度等工艺参数对AgCr合金材料的密度、硬度、导电性、金相结构的影响,总结出制备性能优异的AgCr合金材料的工艺。最后,通过对电路电流及通断比的变化、触头接触电阻的变化和接触表面形貌及成分的分析研究,可综合分析触头材料的电接触性能。通过比较AgCr触头、铜基覆银触头、AgSnO2触头在电流作用下的接触性能,检验AgCr触头是否具有较强的抗电侵蚀能力。研究结果表明：当球磨转速达到一定值,球磨到一定时间,Cr相能部分固溶到Ag相中。适当的球磨工艺参数和烧结温度可以制备出性能相对优异的AgCr合金,其制备的AgCr(Cr含量12 wt%),密度为9.62 g／cm3,硬度为122.3 HV,导电率4.03μΩ·cm,同时烧结体金相结构表明该工艺参数下制备的触头材料组织分散较均匀,无明显团聚现象,具有很好的开发和应用前景。AgCr触头电接触性能分析表明：分别在相同测试条件下,发现AgCr触头电性能要优于铜基覆银触头；而与AgSnO2触头相比,AgCr对称触头材料转移量更大,但是AgSnO2触头接触表面有裂纹生成,并且闭合分断电流达10万次后,AgCr对称触头保持接触电阻低而稳定,同时电路通断比没变化。总体评价：AgCr触头具有较好的电接触性能。更多还原

【Abstract】 Electrical contact is responsible to connect and break the circuit and carry current. Because of its special role, performance of electrical contact materials directly impacts on the reliability, stability, accuracy and service life of electronic products. In the process of connecting and breaking the circuit, electrical contactor comes under electrical erosion, so that it can’t normal work. Thereby, study on electrical contact materials which have the strong anti-electrical erosion has important significance.This paper studies preparation and properties of AgCr contact material, which is prepared by mechanical alloying. Firstly, it researches effect of milling technology on phase, grain size, micro-strain and morphology of AgCr powder by X-ray diffraction and SEM, which includes milling speed and the ratio between the weight of balls and materiel. Secondly, though studying milling technology and sintering temperature impact on density, hardness, conductivity and optical structure of AgCr alloy material, we have gained the best technological parameters with which AgCr alloy material is produced by mechanical alloying. Lastly, though exploring electrical properties of AgSnO2 contactor, silver covering copper-base contactor and AgCr contactor under the DC by analysis of circuital current, contact resistance, SEM micrographs and elemental analysis of contact surface, we can examine whether the AgCr contactor has strong capacity of anti-electric erosion.The results show that Cr phase can be partial solid solution to the Ag phase after a certain time of milling when the milling speed reaches a certain value. AgCr alloy material with superior performance is prepared under the appropriate milling technique and proper sintering temperature. AgCr alloy material which includes Cr content 12 wt% has density of 9.62 g/cm3, hardness of 122.3 HV and conductivity of 4.03μΩ·cm.and its micro structure structure simultaneously showed that the organization distributes more evenly and reunion is not obvious. So this material has good development and application.Comparative analysis of the electrical contact performance indicates that AgCr contact material is superior to silver covering copper-base material with respect to anti-electric erosion. Also it shows that AgCr contactor is more amount of material transfer than the AgSnO2 contactor, but contact surface of AgSnO2 material exist cracks, also steady contact resistance of AgCr contact material and ratio of connecting and breaking of circuit have no change. In summary, AgCr contact material has the good electrical contact performance.更多还原