Corrosion behavior of AZ31 magnesium alloy in the chloride solution containing ammonium nitrate

被引：91

作者：

Cui, Zhongyu ^{[1
]}

Ge, Feng ^{[1
]}

Lin, Yi ^{[1
]}

Wang, Liwei ^{[2
]}

Lei, Li ^{[1
]}

Tian, Huiyun ^{[1
]}

Yu, Mingdong ^{[1
]}

Wang, Xin ^{[1
]}

机构：

[1] Ocean Univ China, Sch Mat Sci & Engn, Qingdao 266100, Peoples R China

[2] Qingdao Univ, Coll Electromech Engn, Qingdao 266071, Peoples R China

来源：

ELECTROCHIMICA ACTA | 2018年 / 278卷

基金：

中国国家自然科学基金;

关键词：

Magnesium alloy; Ammonium; Nitrate reduction; Hydrogen evolution; Pitting corrosion; INDUCED ATMOSPHERIC CORROSION; SALT-SPRAY ENVIRONMENTS; 3.5 WT.PERCENT NACL; ELECTROCHEMICAL-BEHAVIOR; ION CONCENTRATION; STAINLESS-STEEL; MG ALLOY; IN-SITU; ALUMINUM-ALLOYS; TIN CATHODE;

D O I：

10.1016/j.electacta.2018.05.059

中图分类号：

O646 [电化学、电解、磁化学];

学科分类号：

070208 [无线电物理];

摘要：

Corrosion behavior of AZ31 magnesium alloy in NH4NO3- containing chloride solution was investigated by immersion tests, hydrogen evolution collection, electrochemical measurements, and microscopic observation. Addition of NH4NO3 accelerates corrosion due to the deterioration of Mg(OH)(2) by NH4+ and the promotion of cathodic NO3- reaction, which is supported by the buffering effect of NH4+. Hydrogen evolution is suppressed with addition of high concentrations of NH4NO3, attributed to the preferential occurrence of NO3- reduction. Loose and cracked corrosion products, which are mainly composed of Mg-2(OH)(3)Cl center dot 4H(2)O and magnesium hydroxy carbonates, form in the NH4NO3-containing environment. When the NH4NO3 concentration is between 0.005 and 0.03M, autocatalytic pitting corrosion occurs due to the synergistic effects of Cl-, NH4+, and NO3- at the specific concentration range. The H+ (supplied by NH4+ hydrolysis), Cl- in combination with the depolarization effect of NO3- support the autocatalytic growth and eventually perforate the alloy. With the addition of NH4NO3 higher than 0.05 M, corrosion pits with shallow-dish shape form initially and then evolves into general corrosion, because general corrosion is promoted by the decrease of solution pH, suppression of Mg(OH)(2) precipitation, and enhancement of cathodic reactions. (c) 2018 Elsevier Ltd. All rights reserved.

引用

页码：421 / 437

页数：17

共 81 条

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