LaSrCuO4粉体微结构对Ag/LSCO电接触材料性能的影响

Effects of microstructure of LaSrCuO4 powders on properties of Ag/LSCO electrical contact materials

摘要:

以硝酸镧、硝酸铜、硝酸锶等为原料，分别采用固相法、溶胶-凝胶法和共沉淀法合成了不规则颗粒状(LSCOg)、介孔状(LSCOm)和片层状(LSCOl)的LaSrCuO4(LSCO)粉体。采用高能球磨并结合初压-初烧-热压工艺制备出Ag/LSCO电接触材料。利用X 射线衍射(XRD)、扫描电镜(SEM)、金属电导率仪、维氏硬度计和电寿命试验机等对粉体形貌及电接触材料的物理和电学性能进行了表征。结果表明：与Ag/LSCOm、Ag/LSCOl材料相比，Ag/LSCOg电接触材料表现出更加优异的物理性能，其电阻率为2.37 μΩ ? cm，硬度为800 MPa，密度为9.32 g/cm3；但电学性能差异较小，其在AC220V12A开断状态下的燃弧能量为400 mJ、燃弧时间为23 ms，关合状态下的燃弧能量为1500 mJ，燃弧时间为 68 ms。Ag/LSCO电接触材料的主要失效形式是液滴喷溅，微裂纹和孔洞。

Abstract:

Lanthanum nitrate, copper nitrate, strontium nitrate and so on were used as raw materials to synthesize the irregular granular (LSCO_g), mesoporous (LSCO_m) and lamellar (LSCO_l) LaSrCuO₄ (LSCO) powders by solid phase method, sol-gel method and co-precipitation method respectively. Ag/LSCO electrical contact materials were prepared by high-energy ball milling combined with initial pressing, sintering and hot pressing. The morphology of LSCO powders and the microstructure, physical and electrical properties of Ag/LSCO materials were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), conductivity instrument, Vickers hardness tester and electrical life tester. The results show that, compared with Ag/LSCO_m material and Ag/LSCO_l material, Ag/LSCO_g material exhibits a lower resistivity of 2.37 μΩ?cm, higher hardness of 800 MPa, higher average density of 9.32 g/cm^₃. Under the conditions of AC220V 12A, the arcing energy and arcing time of Ag/LSCO_g electrical contact material are 400 mJ and 23 ms for breaking state, 1500 mJ and 68 ms for closing state. The failure modes of Ag/LSCO electrical contact materials are droplet splashing, micro-cracks and micro-holes.