Corrosion And Wear Behavior Of Fe-18Cr-15Mn-0.66N High Nitrogen Austenitic Stainless Steel

High nitrogen austenitic stainless steel(HNSS)has excellent mechanical properties,corrosion resistance and tribological properties,which makes researchers at home and abroad attach great importance to its research and development.In this paper,the effect of aging treatment on the microstructure and corrosion behavior of a Fe-18Cr-15Mn-0.66N high nitrogen stainless steel(HNSS)in 3.5 wt.%Na Cl solution was investigated using a series of electrochemical tests,scanning electronic microscopy(SEM)equipped with energy dispersive X-ray spectroscopy(EDS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The results showed that the aging treatment led to the precipitation of Cr₂N particles along the grain boundaries and their morphologies changed from dispersive particles to continuous network as the aging time increased up to 60min.Aging time had minor influence on corrosion potential and corrosion current density,but resulted in the sharp decrease of the pitting corrosion potential.The passive films behaved as n-type semiconductors,and the densities of the donor in the passive films increased with the aging time,suggesting that the aging treatment deteriorated the protective performance of the passive film.The fraction of stable oxide(Cr₂O₃)in the passive film decreased with aging time.In order to further study the passivation film,through the deep sputtering experiment of XPS,analyses results showed that the passive films formed in this solution were composed of Cr oxide/hydroxide(mainly)and iron oxides(partially).XPS depth profiles suggested that the contents of metallic Cr and Fe increased but these of Cr and Fe oxides/hydroxides decreased as the passive films were approaching the passive film/the HNSS interface.Corrosion,friction and wear experiments on unaged high-nitrogen steel show that under dry wear and0.5mol/L Na Cl solution environment,the wear scar width,wear scar depth and wear amount of the high-nitrogen steel wear surface increase with the load.gradually increase.The wear scar width,depth and amount of wear in 0.5mol/L Na Cl solution are larger than those in dry wear.However,in 0.5mol/L Na Cl solution,the friction coefficient of HNSS is obviously lower than that in dry wear,because the solution plays a role in lubrication,but the experimental results also show that the addition of solution accelerates the damage of the material.Through the test of the open circuit potential of the high nitrogen steel under static-wear effect,it is found that with the increase of the test time,the open circuit potential of HNSS gradually rises in the static state.When the wear begins,the open circuit potential of HNSS drops sharply.The increase in time gradually decreases.After the wear stops,the potential begins to rise.After another wear,the potential drops sharply again,indicating that friction and wear have caused a certain degree of damage to the surface of the material.