Zn-Ni合金渗层的组织结构及腐蚀性能

Microstructure and Corrosion Properties of Zn-Ni Co-cementation Layer

为改善传统渗锌层组织结构及腐蚀性能,采用甲酸镍和锌粉作为渗剂金属,通过机械能助渗法在Q235钢表面制备Zn-Ni合金渗层。结合扫描电镜(SEM)、EDS能谱和X射线衍射仪(XRD),分析Zn-Ni合金渗层的表面、截面和断口形貌;利用极化曲线和电化学阻抗谱(EIS),表征Zn-Ni合金渗层在3.5%NaCl溶液中的电化学行为;通过中性盐雾试验测试Zn-Ni合金渗层的耐腐蚀性能。结果表明:制备得到Zn-Ni合金渗层的厚度为153μm;渗层主要由Γ(Fe_(11)Zn_(40))相、ζ(FeZn_(15))相和Ni_(2)Zn_(11)金属间化合物组成,渗层结合方式属于冶金结合;Zn-Ni渗层中性盐雾试验出现红锈的时间相比渗锌层延长240 h,自腐蚀电位从−1.222 V正移至−0.957 V,渗层电阻提高352Ω·cm^(2);Ni对改善渗层表面组织状态和提高渗层耐腐蚀性具有显著价值。通过添加甲酸镍制备的Zn-Ni合金渗层相比渗锌层组织结构和腐蚀性能得到明显改善。

In order to improve the structure and corrosion performance of the traditional sherardizing layer,nickel formate and zinc powder are used as the infiltrating agent metal,and the Zn-Ni cementation layer is prepared on the surface of Q235 steel by the mechanical energy assisted technology.The surface,cross-section and fracture morphology of the Zn-Ni cementation layer are characterized by scanning electron microscope(SEM),EDS spectroscopy and X-ray diffractometer(XRD);Electrochemical behavior of Zn-Ni cementation layer immersed in 3.5%NaCl solution is analyzed by polarization curve and electrochemical impedance spectroscopy(EIS).Corrosion resistance of Zn-Ni cementation layer is tested by neutral salt spray test.The results show that the thickness of the Zn-Ni cementation layer is 153μm;the layer is mainly composed ofΓ(Fe11Zn_(40))phase,ζ(FeZn_(15))phase and Ni_(2)Zn_(11)intermetallic compound,cementation layer combination method belongs to metallurgical bonding.The neutral salt spray experiment of Zn-Ni cementation layer is longer 240 h than Zn cementation layer when appearing red rust spots,the self-corrosion potential move from−1.222 V to−0.957 V,impedance modulus of layer resistance is increased by 352Ω·cm^(2);Ni has significant value in improving the surface structure and the corrosion resistance of the infiltration layer.Comprehensively show that the Zn-Ni cementation layer prepared by adding nickel formate has significantly improved structure and performance compared to the sherardizing layer.