F.H. Cao
,
L. Guo
,
L.J. Zhang
,
Z. Zhang
,
J.Q. Zhang
金属学报(英文版)
The corrosion behavior of two different aged LY12 alloys in EXCO (234g/L NaCl, 50g/L KNO3, 0.1M HNO3) and MIL-H-600 (35g/L NaCl, 5g/L (NH4)2SO4) solutions were studied using electrochemical impedance spectroscopy (EIS) in conjunction with SEM technique respectively, and the pH variation of the above accelerated corrosion solution during materials corroding was also measured to characterize the corrosion processes. At the beginning of corrosion, EIS plots exhibited two capacitive arcs in the high frequency range (Cdl) and mediate frequency range (Clf) originating from the original corroded surface and the newly formed interface respectively, and a low frequency inductive loop due to the relaxation phenomenon of reaction intermediates. In the EXCO solution, the EIS results showed that once the exfoliation corrosion occurred, the inductive loop disappeared. The results also showed that the exfoliation corrosion susceptibility of state T6 is much higher than that of state T3, but the intergranular corrosion susceptibility has a reverse order. Based on the relationship of EIS results with SEM and metalloscopy morphologies of the corroding substrates and physic-chemical meaning of EIS parameters, an index (Clf / Cdl) has been proposed to characterize the extent of the localized corrosion, which variation tallies with the real corrosion extent correctly. Meanwhile, good agreement was found between the experimental results and the electrochemical model proposed and, good coherence between the electrochemical features and the distribution type of constituent particles of corroding material was observed.
关键词:
electrochemical impedance spectroscope
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null
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null
Z.B. Shao
,
L.J. Zhang
,
Y. Wang
金属学报(英文版)
Peroviskite-type La1_xSrxMnO3 (0≤x≤0.3) was prepared through the solgel process at low temperature (1100℃). The ethylene glycol and citric acid were used to make a sol-gel from an aqueous solution of lanthanum strontium and manganese nitrates. The particle-diameter distribution of powders is from 10 to 50nm, the mean particle size is about 35nm and the specific surface area is about 92.5 to 98.5m2 g-1. Peroviskitetype La1_xSrxMnO3 was synthesized at 1100℃, and the electronic conductivity of La1-xSrxMnO3 is 104-105S.m-1 from room temperature to 1000℃.
关键词:
sol-gel
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null
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null
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