网孔结构La2Sn2O7粉体的制备及其在Ag-电接触材料的制备及性能研究

Preparation of Mesoporous La2Sn2O7 Powder and Its application in Ag based electrical Contact Materials

摘要:

以五水四氯化锡和硝酸镧为原料,采用化学共沉淀法在烧结温度920℃条件下合成了锡酸镧粉体。通过高能球磨法+成型烧结工艺制得Ag-La₂Sn₂O₇电接触复合材料。重点考察了胶凝剂浓度、烧结工艺对La₂Sn₂O₇粉体形貌及物相的影响,并对Ag- La₂Sn₂O₇电接触材料的物理性能进行了分析。研究结果表明：以碳酸氢铵为胶凝剂,于烧结温度920℃,2h条件下获得具有网孔结构的La₂Sn₂O₇粉体；于成型压力1200MPa,烧结温度900℃,6h条件下制得的Ag-La₂Sn₂O₇电接触材料表现出较佳的电阻率和硬度值。经过热挤压工艺,Ag-La₂Sn₂O₇电接触材料发生了大塑性变形,颗粒在热挤压过程中发生流动变形,形成类纤维状结构的排列分布状态,表现出更低的电阻率。

Abstract:

By using tin tetrachloride pentahydrate and lanthanum nitrate as raw materials, Lanthanum stannate powder was prepared by chemical coprecipitation method with sintering temperature of 920℃. And then Ag-La₂Sn₂O₇ electrical contact composites were prepared by high-energy ball milling and sintering process. The effects of sintering temperature, sintering time and surface modifier on the morphology and phase of La2Sn2O7 powder were investigated, and the physical properties of Ag- La₂Sn₂O₇ were analyzed. The results showed that La₂Sn₂O₇ powder with mesoporous structure was obtained with sintering temperature of 920℃, 2h. With the pressure of 1200MPa and sintering temperature of 900℃, 6h, The properties of Ag- La₂Sn₂O₇ showed good electrical resistivity and hardness. After the hot extrusion process, Ag- La₂Sn₂O₇ electrical contact material had undergone large plastic deformation, in this process, the formation of fiber-like structured distribution of the particles observed contributed to obtain lower resistivity.