T91钢和SIMP钢表面AlO_(x)涂层在600℃静态液态铅铋共晶中的稳定性和腐蚀行为

Stability and corrosion behavior of AlO_(x) coating on T91 steel and SIMP steel in static liquid Pb-Bi eutectic at 600 ℃

铁素体/马氏体钢,如T91钢和SIMP钢,被选为第4代铅冷快堆和加速器驱动系统(ADS)的主要候选结构材料.但容器钢与液态铅铋共晶(LBE)在高温下的相容性限制了它们的应用.铁素体/马氏体钢在600℃的LBE中腐蚀严重.为了保护铁素体/马氏体钢免受高温LBE腐蚀,在钢表面制备AlO_(x)(x<1.5)涂层.本文采用磁控溅射法在T91钢和SIMP钢表面制备了AlO_(x)涂层.对表面有涂层的T91钢和SIMP钢以及表面无涂层的T91钢和SIMP钢在600℃的饱和氧浓度的LBE中腐蚀300 h和700 h的结果进行比较.结果表明,涂层钢表面的氧化层比无涂层钢表面的氧化层薄,这表明AlO_(x)涂层可以有效防止铁、铬和氧元素的快速扩散.然而,在LBE中腐蚀700 h后,AlO_(x)涂层出现裂纹,表面有涂层的T91钢和SIMP钢均遭受到明显的氧化腐蚀,说明该涂层在600℃的LBE中可以在短时间内保护基体免受高温腐蚀.但是涂层在600℃的LBE中不能长时间保持稳定.这可能是由于此次实验条件制备的AlO_(x)涂层膜基结合力不强或制备的AlO_(x)涂层里面存在大量的金属铝和结构缺陷.AlO_(x)涂层在LBE中的高温稳定性有待进一步研究.

Ferritic/martensitic steels,such as T91 steel and SIMP steel,are chosen as the main candidates of structural materials for the Generation IV lead-cooled fast reactors and accelerator driven system.However,the compatibility between container steel and liquid Pb-Bi eutectic(LBE) at high temperature limits their applications.The corrosion of ferritic/martensitic steels is serious in LBE at 600 ℃.In order to avoid corroding the ferritic/martensitic steels in LBE,it is proposed to coat AlO_(x)(x < 1.5) on the steel surface.The AlO_(x) coating is conducted on T91 steel and SIMP steel by magnetron sputtering.In this exploratory work,the corrosion results of AlO_(x) coating steel are compared with the corrosion results of the uncoated steel in LBE with a saturated oxygen concentration at 600 ℃ for 300 h and 700 h.The results show that the AlO_(x) coating can effectively prevent the iron chromium and oxygen from diffusing,so the oxide scale of the coated steel is thinner than that of the uncoated steel.However,the coating cracks after 700 h corrosion in LBE.Meanwhile,T91 steel and SIMP steel also suffer serious oxidative corrosion,indicating that the coating can protect the substrate from being corroded by 600 ℃ static LBE in a short time.However,the coating cannot keep stable for a long time in LBE at 600 ℃.This may be due to the weak film base bonding force of AlO_(x) coating prepared under the experimental conditions,or a large number of metal aluminum and structural defects existing in AlO_(x) coating.It is needed to further study the stability of AlO_(x) coating in LBE at elevated temperature.