改性HSn70-1锡黄铜的组织和腐蚀性能研究

Research on Microstructures and Corrosion Resistance of Modified HSn70-1 Brass

设计了一种改性的HSn70-1锡黄铜,并运用XRD、金相显微镜、电化学工作站、SEM、EDS等设备研究其显微组织、极化曲线、浸泡平均腐蚀速率和腐蚀产物成分、失重率、脱锌层深度和形貌。结果表明:在HSn70-1锡黄铜中加入少量Sn、Al和微量P、Ni元素扩大了α相区,细化了晶粒,且以固溶形式存在晶粒内部且无其他析出相;极大地提高开路电位,减小自腐蚀电流密度,交流阻抗从8.49 kΩ增大为17.8 kΩ,有效地抑制腐蚀进行;在3.5%Na Cl溶液中四种合金元素可促进表面腐蚀产物和膜的形成,阻碍腐蚀的继续进行;微量合金元素可提高合金电极电位,很好地抑制Zn优先溶解,脱锌腐蚀深度由280μm减小到25μm。所以相比HSn70-1提高了合金的耐腐蚀性能。

A modified HSn70-1 brass was designed, instruments such as XRD, polarizing microscope, electrochemical workstation, SEM and EDS, etc. were used to analysis microstructure, polarization curve, average corrosion rate and the ingredients of corrosion product, rate of lost mass, the depth and morphology of dezincification layer. Results show that a small amount addition alloy including Sn, Al, P, Ni could expand α-phase area, refine grain, totally exist in grain as solid solution and no other precipitates. It also could greatly increase the open circuit potential and decrease corrosion current density so that AC impedance increased from 8.49 kΩ to 17.8 kΩ, inhibiting corrosion effectively. In 3.5%NaCl solution, four elements joined could promote the formation of corrosion products and protective film on surface to inhibit corrosion process. A small amount of alloy elements improved alloy electrode potential and has a better inhibition of zinc priority to dissolve than HSn70-1. The depth of dezincification corrosion reduced form 280 μm to 25 μm, the modified HSn70-1 improved the corrosion resistance significantly.