Trace The Influence Of Doping Elements On Microstructure And Properties Of Tantalum Wire

Property of tantalum wire is critical to quality of tantalum capacitor. Doping can effectively improve the synthesis property of tantalum wire. Effect of different dopants and various dopants quantity at different annealing temperatures on microstructure and property of tantalum bar and wire were investigated through observation of microstructure, SEM fractograph, analysis of electron probing, observation of TEM, testing of density, hardness and mechanical property at room temperature, DCL(direct current leakage), bending of tantalum wire after sintering and bending after pressing into tantalum powder and sintering in the article. It is illustrated that: the grain of tantalum bar after sintering can be reduced by doping with A or with A and B. Moreover, the grain is finer with the increment of dopants quantity. And the effect of dopant A and B on reduction of the grain is more obvious than that of dopant A, even that sintering is becoming insufficient and the density of tantalum bar tends to be low with the increment of dopant B. The recrystallization temperature of tantalum wire increases and the grain can be reduced with the increment of dopants quantity. At the same time, the effect of dopant A and B on reduction of the grain is more obvious than that of dopant A. The tensile of tantalum wire at room temperature increases with the increment of dopants quantity, while the elongation of its lowers with the increment of dopant A quantity and rises with the increment of dopant B quantity. And the strengthening effect of dopant A and B is more significant than that of dopant A. The DCL(direct current leakage) of tantalum wire doped with A and B is lower than that of tantalum wire doped A or pure one. The DCL of tantalum wire doped with A 400ppm and doped with A 400ppm and B 400ppm is the lowest in the respective kind of tantalum wire. The bending times of tantalum wire after sintering increase with the increment of dopant A or B quantity. On the same condition, the bending time of tantalum wire after pressing into tantalum powder and sintering worsens with the increment of oxygen contents in tantalum powder. The bending time of tantalum wire doped with A and B after pressing into tantalum powder and sintering is better than that of tantalum wire doped A, while that of tantalum wire doped with A is better than that of pure one. Addition of dopants plays a vital role in solution strengthening, dispersion strengthening and fine grained strengthening.