The open-circuit potential,electrochemical impedance spectroscopy,potentiodynamic po-larization,potentiostats polarization,current-time transient measurements,Mott-Schottky analysis,X-ray photoelectron spectroscopy(XPS),Electron Back-Scattered Diffraction(EBSD)methods were used to in-vestigate the passivation behavior of 316L stainless steel fabricated by laser selective melted(SLM 316L)in 0.05 mol/L H2SO4+0.2 mol/L NaCl solution.The results were compared with commercial rolled 316L stainless steel(R 316L).The results showed that the nucleation of passivation film follows continuous mechanism for the both stainless steel.However,the SLM 316L stainless steel has smaller grain size and higher grain boundary density than those of R 316L stainless steel.Therefore,the grow rate of pas-sivation film is fast.The SLM 316L stainless steel took place transpassivation dissolution,while R 316L stainless steel took place pitting corrosion.The SLM 316L stainless steel has better corrosion resistance.The main reasons are the SLM 316L stainless steel has much more low angle grain boundaries without ferrite.Moreover,the passivation film of SLM 316L stainless steel has lower carrier density,lower ratio of O2-/OH-,lower content of NiO and higher content of Cr2O3 compared with R 316L stainless steel.
关键词
材料失效与保护/钝化行为/电化学测试/316L不锈钢
Key words
materials failure and protection/passivation behavior/electrochemical tests/316L stain-less steel
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