采用电化学法和化学浸泡法研究了高温65%LiBr+0. 07mol/L LiOH溶液中，LiNO3对碳钢腐蚀的影响.结果表明，随LiNO3浓度增加碳钢腐蚀 速率降低，复合添加150 mg/L Na2MoO4后，碳钢在100mg/L LiNO3时腐蚀速率出现最 小值.通过计算NO-3和MoO2-4还原平衡电极电位，发现NO-3优先还原形成 内层以Fe的氧化物为主的膜是由于NO-3具有较高的还原电极电位.LiNO3小于10 0 mg/L时，复合添加的MoO2-4在外层得以还原形成缺氧型MoO2，建立起稳定的双 层膜结构.当LiNO3浓度大于100 mg/L后，NO-3对膜层中MoO3优先侵蚀，加速Br- “楔入” 钝化膜历程，从而破坏了双层膜结构.
By means of electrochemical measurements and chemica l immersion experiments,this paper investigates the inhibition effect of lithium nitrate on corrosion of carbon steel in 65%LiBr +0.07mol/L LiOH solution at 173 ℃.The results show that,the corrosion rate of carbon steel decreases with incre ase of LiNO3 concentration.Combined with 150 mg/L Na2MoO 4 in this solution,the corrosion rate shows a minimum at 100mg/L LiNO3.T hrough calculation of the equilibrium potentials of the reduction electrodes for NO-3 and MoO2-4,it is revealed that NO-3 possessed higher reduc tion electrode potential,therewith,NO-3 was reduced firstly,which is favior to the formation of an inner film with ferric oxide as its main com ponent.In addition,an oxygen-deficient MoO2 as outer-layer is formed by reduct ion of MoO2-4 when LiNO3 is less than 100 mg/L,and stable double film is built up.However,when LiNO3 is more than 100 mg/L,NO-3 reacts with MoO 3 preferentially and results in Br- coupling in the formed passive film,w hich further damages the double film and thus increases the corrosion rate to a large extent.
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