Effect of thermal treatment and fluoride ions on the electrochemical corrosion behavior of selective laser melted CoCrW alloy
Effect of thermal treatment and fluoride ions on the electrochemical corrosion behavior of selective laser melted CoCrW alloy
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DOI：
10.1016/j.jallcom.2017.09.318
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发表时间：
2018-01
影响因子：
6.2
通讯作者：
Yanjin Lu;S. Guo;Yang Yang-Yang;Yujing Liu;Yu Zhou;Songquan Wu;Chaoqian Zhao;Jinxin Lin
中科院分区：
文献类型：
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作者：
Yanjin Lu;S. Guo;Yang Yang-Yang;Yujing Liu;Yu Zhou;Songquan Wu;Chaoqian Zhao;Jinxin Lin
采用开路电位（OCP）、动电位极化、电化学阻抗测量（EIS）等方法研究了不同热处理后的as-SLMed CoCrW合金在含氟和不含氟的0.9% NaCl溶液中的电化学腐蚀行为。结果表明：组织均匀的SLMed CoCrW在1150℃热处理后再进行水淬处理，对电解液的耐腐蚀性较好；而在1150℃热处理后再进行炉冷处理，产生大量连续块状析出物的合金易受腐蚀。XPS结果表明，氟离子的加入促进了F−、Cl−和Na+在钝化膜上的吸附。氟离子通过改变钝化膜的组成，略微加速了SLMed CoCrW合金的腐蚀，从而降低了钝化膜的防护性。因此，本文提出了一种与氟离子对as-SLMed CoCrW合金的腐蚀机制。
The electrochemical corrosion behaviors of as-SLMed CoCrW alloy after different heat treatments were investigated in 0.9% NaCl solution with and without the fluoride ions by open circuit potential (OCP), potentiodynamic polarization, electrochemical impedance measurements (EIS). The results showed that the SLMed CoCrW with a homogeneous structure experienced heat treated at 1150 °C followed by water quenching exhibited the better corrosion resistance to the electrolyte, whereas the alloy heat treated at 1150 °C followed by furnace cooling with a large amount of continuous blocky precipitates was susceptible to the corrosion. The XPS results indicated that the fluoride ions addition promoted the absorption of F−, Cl−and Na+on the passive film. The fluoride ions slightly accelerated the corrosion of the SLMed CoCrW alloy by changing the composition of the passive film, thereby reducing the protectiveness of the film. Accordingly, a corrosion mechanism associated with the fluoride ion to the as-SLMed CoCrW alloy was proposed herein.