反应等离子喷涂TiN涂层电化学腐蚀行为

利用电化学阻抗谱等电化学方法及扫描电镜(SEM)技术,研究了反应等离子喷涂TiN涂层在模拟海水中的电化学腐蚀行为.研究结果表明:TiN涂层的自腐蚀电位高于基体,涂层对基体能起到良好的腐蚀屏蔽作用;腐蚀介质通过涂层的通孔、微裂纹等缺陷渗入涂层与基体的界面腐蚀基体,从而使涂层电阻下降、电容增加,所产生的腐蚀产物在一定程度上可以抑制腐蚀反应的进行,但不会阻止基体局部腐蚀的继续进行.涂层的孔隙是造成涂层电化学腐蚀的主要原因.

Electrochemical corrosion behavior of reactive plasma-sprayed TiN coatings

The electrochemical corrosion behavior of TiN coatings prepared by reactive plasma spraying was studied in seawater by SEM technology and electrochemical methods such as electrochemical impedance spectroscopy.The results showed that the corrosion potential of TiN coatings was higher than that of the substrate and the coatings had a good corrosion shielding effect on the substrate.The coatings resistance declined and capacitance increased because the corrosion medium permeated into the coating/metal interface through pinholes and microcracks immediately. Due to the products of corrosion the corrosion was restrained, but the products can not stop the local corrosion of the substrate. The electrochemical corrosion of the coatings were mainly as the result of holes in the coatings.