表面处理对镍基合金加热管腐蚀行为的影响

通过动电位扫描测试、XRD分析、SEM观察,研究了镍基合金Incoloy800和Incoloy840镍基合金加热管试样经过HNO3钝化、涂覆SiO2膜两种表面处理后抗腐蚀性能的变化.结果表明:钝化处理显著提高Incoloy840镍基合金的点蚀电位和保护电位,而对Incoloy800镍基合金的保护电位影响较小,几乎没有改变其点蚀电位;以正硅酸乙酯作为前驱体,两种PEG表面活性剂作为模板剂,在静电和氢键驱动力的共同作用下组装生成SiO2溶胶,涂覆在镍基合金加热管表面形成的膜层均匀致密、性能良好;涂覆SiO2膜层显著提高了两种镍基合金加热管的自腐蚀电位和点蚀电位.上述表面处理工艺均提高了两种镍基合金加热管的抗腐蚀性能.

Influnce of Surface Treatments on Corrosion Performance of Ni-based Alloys for Heating Tube

Corrosion performance of Ni-base alloys Incoloy800 and Incoloy840 after HNO3passivation treatment or application of SiO2 coating was studied by potentiodynamic polarization test,XRD and SEM.The result showed that after HNO3passivation treatment the pitting potential and protection potential of Incoloy840 increased significantly,while Incoloy800 showed a few change in protection potential and little change in pitting potential.Flaw-less SiO2 coating can be applied on the two alloys with TEOS and two surfactants(PEG200,PEG20000).The open-circuit potential and pitting potential of the two Ni-based alloys increased significantly after application of SiO2 coating.Therefore,the corrosion resistance of the two Ni-based alloys may be significantly enhanced after surface treatments above.