摘要
研究了X80管线钢在3.5%NaCl溶液中的电化学腐蚀行为。结果表明:经离子渗氮的样品,表面硬度显著提高,且随渗氮温度的升高而增加;渗氮层的耐蚀性明显优于基体材料,腐蚀电流密度降低一个数量级;腐蚀电位明显正移。当渗氮温度为450℃时,样品渗氮层由ε相和少量的γ'相构成,表面硬度约为810 HV,耐蚀性最好,腐蚀电流最小,约为0.56μA/cm2,腐蚀电位最高,约为-214 m V。当渗氮温度为570℃时,样品渗氮层全部为γ'相,表面硬度约为930 HV,耐蚀性明显降低。离子渗氮温度显著影响X80钢表面渗氮层的相组成,引起表面硬度和耐蚀性不同。
X80 pipeline steel was nitridated by plasma nitriding and then its electrochemical corrosion behavior in 3.5% NaCl solution was studied by means of polarization curves and impedance spectroscopy. As compared to the bare X80 steel, the nitriding steels exhibit a remarkable increment in hardness, which increases with the rising nitriding temperature; the nitriding steels possess higher corrosion resistance with a lower corrosion current density by about one order of magnitude.The formation of ε phase（Fe3N） with a small amount of γ ＇ phase（Fe4N） dominates on the surface of the steel nitridated at 450 ℃, resulting in a maximium in corrosion potential about-214 m V and a minimum in corrosion current density about 0.56 μA/cm2, respectively, togeter with the hardness increase to about 810 HV. Only the γ ＇phase forms on the surface of the steel nitridated at 570 ℃,which contributes to the hardness increase to 930 HV and a obvious decrease of corrosion resistance. The plasma nitriding temperature determines the phase constitutes of the surface nitriding layer and affects greatly its hardness and corrosion resistance.
出处
《腐蚀科学与防护技术》
CAS
CSCD
北大核心
2015年第4期345-348,共4页
Corrosion Science and Protection Technology
基金
辽宁省自然科学基金项目(201202127)资助
关键词
X80管线钢
离子渗氮
耐蚀性
硬度
X80 pipeline steel
plasma nitriding
corrosion resistance
hardness
