【作者】 叶慧；

【导师】 俞斌； 杨文忠；

【作者基本信息】 南京工业大学 ， 应用化学， 2003， 硕士

【摘要】 本文采用失重法、极化曲线法、和XPS表面分析技术等方法研究了PSI值、氯离子浓度、HEDP和锌盐对碳酸氢钙溶液中的碳钢腐蚀行为的影响；用静态阻垢法研究了HEDP等阻垢分散剂对不同PSI值的碳酸氢钙溶液的阻垢分散作用。实验采用的碳酸氢钙溶液的PSI值分别为3.0、4.0、5.0、6.0，氯离子浓度为1000.0~ 6000.0ppm。 一、失重法结果表明： 当碳酸氢钙溶液的PSI值小于6.0，即使不加任何缓蚀剂，溶液也有一定的缓蚀作用。 二、极化曲线研究表明： 1．碳钢在不同PSI的碳酸氢钙溶液中是活化－钝化体系，且随着PSI的减小，碳钢的腐蚀速度降低； 2．随着PSI值的减小，碳钢的过钝化电位正移，致钝电流密度减小，钝化区的电位范围变宽； 3．碳钢的腐蚀速率随着氯离子浓度的增加而增大； 4．氯离子能破坏碳钢表面的沉积膜，加速碳钢的腐蚀； 5．在不含氯离子的不同PSI值的碳酸氢钙溶液中，HEDP和锌盐的加入使得碳钢的腐蚀速率减小，当PSI为3.0或4.0时，其维钝电流密度变小； 6．单独加入HEDP或锌盐，使得碳钢的腐蚀速率减小，但是减小的幅度并不大； 7．同时加入HEDP和锌盐，碳钢的腐蚀速率明显变小，说明HEDP和锌盐有明显的协同效应； 8．过高的氯离子浓度大大地破坏了HEDP、Zn2＋和碳酸钙形成的膜。 三、XPS表面分析技术研究表明： 1．碳钢表面的保护膜主要是由Ca (Ⅱ) 、C (Ⅳ) 、－OH和O2－组成，另外还有少量的Fe；<WP=4> 2．当碳酸氢钙溶液的PSI值小于6.0时，碳酸氢钙溶液能在碳钢表面形成一层碳酸钙保护膜，抑制了金属的腐蚀； 3．碳钢在含5ppmHEDP，PSI为3.0的碳酸氢钙溶液中浸泡后表面形成的膜主要由Ca (Ⅱ) 、C (Ⅳ) 和O (Ⅱ) 组成，但是表面膜中检测不到P；4．碳钢在含2ppmZn2+，PSI为3.0的碳酸氢钙溶液中浸泡后表面形成的膜主要由Ca (Ⅱ) 、C (Ⅳ) 、O (Ⅱ) 和Zn (Ⅱ) 组成； 5．碳钢在含2ppmZn2+和5ppmHEDP，PSI为3.0的碳酸氢钙溶液中浸泡后表面形成的膜主要由Ca (Ⅱ) 、C (Ⅳ) 、O (Ⅱ) 、Zn (Ⅱ) 以及P组成，但P的存在形式比较复杂，从微观上证明了HEDP和锌盐具有协同作用。 四、静态阻垢实验表明： 1．在试验所采用的全部PSI范围内，HEDP的阻垢效率不太理想； 2．HEDP对碳酸氢钙溶液的阻垢率随着PSI值的增加而增大。更多还原

【Abstract】 The corrosion behaviors of carbon steel in Ca (HCO3) 2 solution with different PSI, the effect of chloride and the effect of HEDP and zinc salt on the corrosion behavior of C.S were studied by weight loss, polarization curves and XPS methods. The performances of scale inhibitor, like HEDP, on Ca (HCO3) 2 solution with different PSI were evaluated by static test.1. The corrosion behaviors of carbon steel in Ca (HCO3) 2 solution with different PSI(1) The corrosion behaviors of carbon steel in Ca (HCO3) 2 solution is typical activation-passivation system and the carbon steel’s corrosion rate raised by PSI; (2) The out layer of protective film formed by Ca (HCO3) 2 solution on the surface of carbon steel comprised Ca (Ⅱ) 、C (Ⅳ) 、 O (Ⅱ) and O2－ mainly;(3) When the value of PSI of Ca (HCO3) 2 solution is lower than 6.0,it can form a film on the carbon steel surface to protect C.S.2. The effect of chloride on the corrosion behavior of carbon steel(1) The carbon steel’s corrosion rates are raised by the concentration of chloride;(2) The chloride can spoil the film on the carbon steel’s surface and accelerate the corrosion rate of carbon steel.3. The effect of chloride and the effect of HEDP and zinc salt on the corrosion behavior of carbon steel(1) When there is no chloride in the Ca (HCO3) 2 solution with different PSI, if added HEDP or Zn2+ in the solution only, the corrosion rate of carbon steel would decrease; when the value of PSI is 3.0 or 4.0, the ip of C.S turns to be smaller;(2) If added HEDP or Zn2+ in the Ca (HCO3) 2 solution only, the corrosion rate of carbon steel would decrease slightly;(3) If added HEDP and Zn2+ in the Ca (HCO3) 2 solution at the same time, the corrosion rate of carbon steel would decrease obviously;(4) If the concentration of chloride is too high, it could spoil the film on the carbon steel’s surface;<WP=6>(5) The out layer of protective film formed by Ca (HCO3) 2 solution (PSI=3.0, HEDP= 5ppm) on the surface of carbon steel comprise Ca (Ⅱ) 、C (Ⅳ) and O (Ⅱ) mainly, but do not discovery element P;(6) The out layer of protective film formed by Ca (HCO3) 2 solution (PSI=3.0, Zn2+= 2ppm) on the surface of carbon steel comprise Ca (Ⅱ) 、C (Ⅳ) 、O (Ⅱ) and Zn (Ⅱ) mainly;(7) The out layer of protective film formed by Ca (HCO3) 2 solution (PSI=3.0, HEDP= 5ppm, Zn2+= 2ppm) on the surface of carbon steel comprise Ca (Ⅱ) 、C (Ⅳ) 、O (Ⅱ) 、Zn (Ⅱ) and P; but the exist situation of P is complex.4. The scale inhibition performances of HEDP on Ca (HCO3) 2 solution with different PSI(1) In the range of the value of PSI adopted in the experiments, the scale inhibition performances of HEDP are not so good;(2) The rates of scale inhibition of HEDP are raised by the concentration of chloride.更多还原