含钛高炉渣制备钢表面防腐涂层基础研究

发布时间：2018-03-30 00:14

  本文选题：钛金属　切入点：溶解度　出处：《华北理工大学》2017年硕士论文

【摘要】：传统的电化学法制备钛金属主要以纯氯化物为电解介质,制取钛金属粉末。而在NaCl-KCl-NaF熔盐体系中,以碳钢为工作电极,可以在其表面制备钛金属防腐涂层。钛镀层不仅提高了碳钢基体的耐腐蚀性能,而且提供了一种更加简便的获得钛金属的工艺,该工艺的提出将碳钢基体的力学性能与钛金属的耐腐蚀性能结合在了一起。利用等温饱和法分析TiO_2在NaCl-KCl-Na F熔盐体系中的熔融和溶解特性,确定了TiO_2在熔盐体系内的饱和溶解时间为4.0h,并且熔盐组分中,随着NaF摩尔分数的增加,TiO_2在熔盐体系中的溶解量升高;对不同配比的熔盐进行差热分析,可以确定当NaF含量较少时,TiO_2影响着整个熔盐体系的初晶温度,而当NaF含量较高时,改变TiO_2的质量分数初晶温度基本保持不变。采用循环伏安法和方波伏安法对NaCl-KCl-NaF-TiO_2熔盐体系中的Ti(IV)离子的电化学还原机理进行了分析。由实验结果可以确定Ti(IV)离子经三步还原为钛金属,即Ti(IV)→Ti(III)→Ti(II)→Ti,并且该还原过程为不可逆反应;采用计时电流确定了钛离子在阴极表面的形核机理为三维半球型瞬时形核过程。通过碳钢表面电沉积钛的实验研究可以确定,当沉积温度为800℃,电沉积电流为1.5A,沉积时间为1.0h情况下,获得的沉积层质量最好;通过对比直流电沉积和脉冲电沉积试样的表面形貌,可以确定脉冲电沉积获得的沉积层中晶粒尺寸更小,且沉积层更加致密、均匀、表面平整。在3.5%的NaCl水溶液中,采用极化曲线和交流阻抗测试方法研究了沉积试样的耐腐蚀性能。测试结果表明,当沉积电流为1.5A,沉积时间为1.0h时所得的试样的耐腐蚀性最为优异。与碳钢基体相比,即使碳钢表面只沉积少量的钛,也能显著提升其耐腐蚀性能。并且脉冲沉积试样的防腐特性明显优于直流沉积试样。
[Abstract]:Titanium powder was prepared by traditional electrochemical method using pure chloride as electrolytic medium, while carbon steel was used as working electrode in NaCl-KCl-NaF molten salt system. Titanium coating not only improves the corrosion resistance of carbon steel substrate, but also provides a more convenient process for obtaining titanium metal. This process combines the mechanical properties of carbon steel substrate with the corrosion resistance of titanium metal. The melting and dissolution characteristics of TiO_2 in NaCl-KCl-Na F molten salt system are analyzed by isothermal saturation method. The saturated dissolution time of TiO_2 in molten salt system is 4.0 h, and the dissolved amount of TiO-2 in molten salt system increases with the increase of NaF molar fraction. It can be ascertained that TiO2 affects the initial crystal temperature of the whole molten salt system when the content of NaF is low, and when the content of NaF is high, The electrochemical reduction mechanism of TiO_2 in molten salt system was analyzed by cyclic voltammetry and square wave voltammetry. Three steps of reduction to titanium, Tijiv). 鈫扵ijii). 鈫扵iII). 鈫扵he nucleation mechanism of titanium ions on the cathode surface is determined to be a three-dimensional hemispherical instantaneous nucleation process, and the experimental study on the electrodeposition of titanium on the surface of carbon steel can be confirmed. When the deposition temperature is 800 鈩，

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