TZM合金在酸、碱腐蚀介质中的腐蚀行为研究

Study on Corrosion Behavior in Acid and Alkaline Medium of TZM Alloy

摘要:

对TZM、掺杂La-TZM合金进行酸性和碱性介质腐蚀试验,设计腐蚀周期分别为10d、30d、50d、70d四个阶段。通过对两种TZM和掺杂La-TZM合金在两种腐蚀介质中不同腐蚀周期的质量损失、失重速度、平均腐蚀率以及腐蚀形貌的研究与比较,分析TZM合金在两种介质中的腐蚀机理,以及掺杂La对于TZM合金的耐酸、碱腐蚀性能的影响。研究表明TZM合金在酸性介质中主要发生电池反应,阳极金属溶解,阴极析氢；腐蚀在金属表面缺陷、杂质富集、晶界处以及位错处优先进行,并且表面存在划痕处的小于0.0001inch (0.025~0.1mm)的窄缝处发生缝隙腐蚀。TZM合金在碱性介质中几乎不发生腐蚀；掺杂稀土元素镧可以略微提升TZM合金的耐蚀性,但提升效果不显著。

Abstract:

Researched the corrosion behavior of TZM and La doped TZM alloy in acid and alkaline medium. Designed four corrosion period stages as 10days, 30days, 50days, 70days for respectively. Investigated and compared mass loss condition, weight loss condition, average corrosion rate and corrosion morphology. Anlysis the corrosion mechanism in acid and alkaline of TZM alloy and the effect of La doped on corrosion resistance of TZM alloy. The study shows TZM alloy corroded in acid major set off cell reaction and anode dissolved while cathode hydrogen evolution. Corrosion prior occurred at surface defect, impurty, grain boundary and dislocation. Crevice corrosion morphology was observed at the narrow slit which formed by scratch and width less than 0.0001 inch (0.025~0.1mm). Corrosion hardly occurred in alkaline medium. La doping could slightly rising the corrosion resistance of TZM alloy, but the improvement is not significant