ga bi合金化alznsn系牺牲阳极材料及其热处理分析-ga bi alloying alz nsn sacrificial anode material and its heat treatment analysis.docx

摘要compound alloying. Through analyzing EIS of Al-Zn-Sn series alloys, the corrosive mechanism of Al-Zn-Sn and Al-Zn-Sn-Bi which chief activating elements are Sn or Bi can be characterized by equivalent circuit of RS(CpRp(QR1)(L1Rad1)(L2R ad2)). And equivalent circuit of RS(QR1(C1Rw1)(C2Rw2) (LRad)) can demonstrate activation mechanism of Ga which is chief activation-element in Al-Zn-Sn-Ga and Al-Zn-Sn-Ga-Bi alloys.The heat treatments on new aluminum base anode materials have also been studied. The results show that annealed and solution treatment between 470℃ and 530℃cannot markedly improve the electrochemical performances of Al-Zn-Sn-0.01Gaand Al-Zn-Sn-0.02Ga alloys. But Al-Zn-Sn-0.015Ga alloy exhibits better comprehensive properties with negative operating potential, uniform dissolution andhigh efficiency of more than 95.0%, which treated by annealed at 480℃ or solution at460℃. Al-Zn-Sn-Ga-Bi alloys with solution treatment have high and steady negative operating potential, uniform dissolution which current efficiency decline slightly.Alloy with solid solution at 480℃ exhibit optimum comprehensive performance withopen circuit potential of -1.071V, operating potential of -1.063V~-1.078V, current efficiency reach 96.6% and dissolution homogeneous.As analyzing，It is believed that corrosion process of Al-Zn-Sn-Ga-Bi alloy iscomposed of “second-phase priority dissolution” mechanism of segregation phase and “dissolution-deposition” mechanism of chief activation elements(Ga)which solution in matrix. The change of dominant factors in activation process under different treatments led to differences of corrosion appearance. As more second-phase or segregation phase dispersed in cast and annealed alloys, the “second-phase priority dissolution” mechanism of them become control step in electrode reaction, this function cause pit corrosion in-depth development and form localized corrosion morphology. But the “dissolution-deposition” mechanism of Ga becomes a key fact