Effect Of Cerium On High Temperature Oxidation And Corrosion Resistance Of 1Cr13 Martensitic Stainless Steel

In this paper,1Cr13 martensitic stainless steel was selected as the research target.Firstly,the effect of cerium on the high temperature oxidation resistance of 1Cr13stainless steel under different oxidation temperatures has been explored.Secondly,the effect of cerium on the corrosion resistance properties of 1Cr13 stainless steel was also investigated by double loop electrochemical potentiodynamic reactivation?DL-EPR?test and potentiodynamic polarization measurement respectively.Meanwhile,studying on the compound effect of between cerium and molybdenum.As a result,this study will provide theoretical basis and new ideas for the use of cerium in1Cr13 stainless steel.In general,the main results obtained in this paper are as follows:?1?The high-temperature oxidation behavior of 1Cr13 stainless steel was investigated at 700-900? in the air by cyclic oxidation experiments.It is showed that cerium addition is found to reduce the oxidation rate of 1Cr13 stainless steel by modification of transport processes,changing the ion transport mechanism from the principally Cr³⁺ions'outward diffusion into the principally O^2-anions'inward diffusion.The reason of oxide scale formed on the sample containing cerium is more protective than the sample without cerium that cerium is beneficial to form protective particle MnCr₂O₄.When being oxidized at 900?,the sample containing cerium shows less number of pores at the interface of the scale than the sample without cerium,and cerium segregation is found in this area,which suggests cerium reduces the pores'formation and enhances the scale adhesion.?2?This paper investigated that the effect of cerium on intergranular corrosion resistance of 1Cr13 martensitic stainless steel by double loop electrochemical potentiodynamic reactivity measurement method under different heat treatment conditions.When the tempered temperature was 550?,650? and 700?,the intergranular corrosion degree of the sample containing cerium was reduced and the reactivation rate?Ir/Ia?was decreased.The result shows that the segregation of cerium at the grain boundaries effectively reduces the precipitation and segregation of chromium carbides,which ultimately decreases the chromium depletion at the grain boundary.As a result,cerium improves to intergranular corrosion resistance of 1Cr13martensitic stainless steel.?3?Compared with the corrosion resistance of 1Cr13 stainless steels treated with different heat treatment,which revealed that the tempering temperature increases continuously and the chromium-rich carbides of all stainless steels were also increased.More importantly,the Ir/Ia ratio of all stainless steels was continuously decreased,namely the intergranular corrosion resistance decline.To analyze the cause of this phenomenon,it is suggested that the diffusion rate of chromium is increased by tempering temperature being increased so that the chromium depleted zone at the grain boundary is continuously bridged.In conclusion,it can be seen that the intergranular corrosion resistance of 1Cr13 stainless steel is also constantly increased by tempering temperature being increased.?4?The effect of cerium element on the pitting corrosion resistance of 1Cr13stainless steel was studied.The results shows that the number pitting sites of the sample containing cerium decreased as well as its size and depth under different heat treatment conditions,and the pitting potential is also increased,accordingly.The reason for this analysis is that cerium not only bridges the chromium depleted zones at the grain boundary,but also purifies molten steel and modifies inclusions,which improves the pitting corrosion resistance of 1Cr13 stainless steel,effectively.?5?This study also showed that the compound effect between cerium and molybdenum can further improve the high temperature oxidation and corrosion resistance of 1Cr13 stainless steel.