The Study On Nano-Doped AgSnO₂ Contact Material

ABSTRACT Sol-gel method is used to prepared SnO2 powder nano-doped with oxidates andthe electrical conductivity of SnO2 and infiltration between oxidates and silver areimproved by coating process, through which AgSnO2 contact materials have lowcontact resistance, good physical and thermalperformances. SnO2 nano-doped with oxidates is analyzed by TEM. The relationship betweennano-doped SnO2 gel and temperature is obtained using DTA-TG and XRD. Thedopant with excellent physical performances is obtained through analysis of physicalperformances of samples such as density and electrical conductivity. The chemicalcompositions and grain size of cladded SnO2-TiO2 powder are analyzed using XRD.Using SEM and EDS investigate the deposition of silver on SnO2-TiO2 particles. Thephysical performances of Ag (SnO2-TiO2) contact materials, such as electricalconductivity, hardness and density are measured and their thermal performance isanalyzed using DTA-TG. The results are shown as follows: SnO2 nano-doped with oxidates (TiO2,ZnO,Sb2O3,CuO) can be prepared by sol-gel method, whose size is about 50nm; theanalysis of DTA-TG and XRD shows that the optimal temperature is 500℃ and thatsubstitution solid solution is formed between SnO2 and dopant ions. The analysis ofphysical performances of sintered nano-doped SnO2 particles indicates that Ti is theoptimal dopant ion. Coated SnO2-TiO2 powder can be distributed homogenously onsilver substrate, which strengthen the bonding strength and infiltration betweenSnO2-TiO2 and silver. The thermal and physical analysis shows that mech-physicaland thermal performances of Ag(SnO2-TiO2) contact materials are improved throughpowder coating process. The optimal coating process is: mixing for 30 minutes;adding hydrazine hydrate lately.