稀土镧铈对Q355NHq钢在模拟海洋大气环境中腐蚀行为的影响

Effect of Rare Earth Lanthanum and Cerium on Corrosion Behavior of Q355NHq Steel in Simulated Marine Almosphere Environment

通过盐雾腐蚀试验和电化学测试,研究了四种稀土含量的(Q355NHq)钢在模拟海洋大气环境中的腐蚀行为,并通过原位浸泡试验研究了钢中两种典型夹杂物在含Cl-环境中的形貌及成分。结果表明:当稀土元素质量分数为0.017%时,试样的腐蚀速率最小,在盐雾试验24h后锈层中的α-FeOOH含量最高;随着钢中稀土含量的增加,电荷转移电阻R_(ct)呈现先升后降的趋势,当稀土元素质量分数为0.017%时,试样的腐蚀电流密度最小,Rct值最大,约为3934Ω·cm^(2);在含Cl^(-)环境中浸泡后,稀土改性后钢中的RE_(x)O_(y)夹杂物较CaS-Al_(2)O_(3)夹杂物表现出更好的耐蚀性。

The corrosion behavior of Q355NHq steel with four rare earth concentrations in simulated marine atmosphere environment was studied by salt spray corrosion test and electrochemical test.The morphology and composition of two typical inclusions in the stels in Cl-containing environment were studied by in-situ immersion test.The results show that when the mass fraction of rare earth elements was 0.017%,the corrosion rate of the sample was the smallest,and the content ofα-FeOOH in the rust layer was the highest after 24 hours of salt spray test.With the increase of rare earth concentration in the steel,the charge transfer resistance Ret increased first and then decreased.When the mass fraction of rare earth elements was 0.017%,the corrosion current density of the sample was the smallest and the R_(ct)value was the largest,which was about 39342.cm^(2).After soaking in CI^(-)-containing environment,RE_(x)O_(y)inclusions in the steel modified by rare earth showed better corrosion resistance than CaS-Al_(2)O_(3)inclusions.