Cathodic cage plasma nitriding of austenitic stainless steel (AISI 316): influence of the working pressure on the nitrided layers properties
Cathodic cage plasma nitriding of austenitic stainless steel (AISI 316): influence of the working pressure on the nitrided layers properties
复制标题
奥氏体不锈钢 (AISI 316) 的阴极笼式等离子渗氮：工作压力对渗氮层性能的影响
DOI：
10.1590/s1516-14392013005000197
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发表时间：
2013
影响因子：
1.7
通讯作者：
C. Alves
中科院分区：
文献类型：
--
作者：
R. Sousa;F. O. D. Araújo;L. C. Gontijo;J. D. Costa;I. O. Nascimento;C. Alves
在这项工作中，工作压力对AISI 316奥氏体不锈钢表面使用阴极笼等离子体氮化技术（CCPN）的氮化处理所产生的层的特性的影响进行了评估。处理在723 K的温度下在120、250和500 Pa的工作压力下进行5小时。通过光学显微镜、X射线衍射、电化学电位曲线等手段研究了镀层的形貌、组织和耐蚀性。分析了工作压力对渗层厚度、显微硬度和耐腐蚀性的影响。测量了极化后样品的E×i曲线和电化学阻抗，以研究在阳极溶液中制备的膜内离子迁移的影响。测试了薄膜的电化学阻抗，表明薄膜具有明显的电容行为。对于在120 Pa压力下的处理，我们发现氮化物Fe 3N、Fe 4N和CrN。对于在250 Pa的压力下的处理，CrN消失，并且观察到的相是氮化物Fe 3N、Fe 4N和S相。对于500 Pa的处理压力，氮化层的耐腐蚀性增加，由X射线衍射图中S相的优势证实。另一方面，在250 Pa的压力下渗氮的样品在NaCl溶液中浸泡时表现出非常不稳定的阻抗行为，表明在该特定工作压力下的处理对等离子体渗氮AISI 316不锈钢表面的耐腐蚀性具有负面影响。
In this work, the influence of working pressure on the characteristics of the layers produced by the nitriding treatment on the AISI 316 austenitic stainless steel surface using the Cathodic Cage Plasma Nitriding technique (CCPN) is assessed. The treatments were carried out at a temperature of 723 K for 5 hours under working pressures of 120, 250 and 500 Pa. The morphology, microstructure and corrosion resistance were studied through optical microscopy, x-ray diffraction, and electrochemical potential curves. We analyzed the effects of working pressure on the layer thickness, microhardness and corrosion resistance. The E×i curves and the electrochemical impedance of polarized samples were measured in order to investigate the effect of the ion transfer inside the produced film placed into the anodic solution. The electrochemical impedance of the films were measured, and showed an apparent capacitive behavior. For treatment under a pressure of 120 Pa we found the nitrides Fe3N, Fe4N and CrN. For treatment at a pressure of 250 Pa, the CrN disappears and the observed phases are the nitrides Fe3N, Fe4N and the S-phase. For a treatment pressure of 500 Pa there is an increase in the corrosion resistance of nitrided layers, confirmed by the predominance of S-Phase in the x-ray diffraction pattern. On the other hand, the sample nitrided under the pressure of 250 Pa showed very unstable impedance behavior when immersed in NaCl solution, indicating that the treatment at this specific working pressure has a negative effect on the corrosion resistance of plasma nitrided AISI 316 stainless steel surfaces.