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采用恒电位计时电流法研究了304不锈钢在0.5mol/L NaCl介质中孔蚀发展过程及缓蚀剂对孔蚀发展的抑制作用,同时用原子吸收光谱(AAS)测定合金各组分元素的溶解量。结果表明:304不锈钢蚀孔内,铬元素以三价,铁、镍和锰以二价离子形式溶解,缓蚀剂PD不改变各元素溶解的价态。极化电位对孔蚀自催化效应有显著影响。哌啶对304不锈钢的孔蚀发展过程有良好的缓蚀作用。PD对各合金元素存在“选择性抑制”效应,降低了各元素的溶解速度,弱化孔蚀自催化效应。PD增强孔内沉积层阻力,促使蚀孔向发展速度较慢的类型转变。根据孔蚀发展动力学模型,讨论了PD的缓蚀机制。
The development of pitting corrosion of 304 stainless steel in 0.5 mol / L NaCl medium and the inhibition of corrosion inhibitor on the pitting corrosion were studied by potentiostatic current method. At the same time, the atomic absorption spectroscopy (AAS) the amount. The results show that the chrome element is trivalent, while the iron, nickel and manganese ions are dissolved in the form of divalent ions. The corrosion inhibitor PD does not change the valence of each element. Polarization potentials have a significant effect on the pitting autocatalytic effect. Piperidine 304 stainless steel pitting development process has a good corrosion inhibition. PD has a “selective inhibition” effect on alloying elements, reducing the dissolution rate of each element and weakening the pitting autocatalytic effect. PD enhances the resistance of the deposition in the hole, prompting the hole to the slow development of the type of change. According to the pitting development kinetics model, the corrosion inhibition mechanism of PD is discussed.