10CrMoAI热轧薄板不同周期盐雾腐蚀的对比分析

目的揭示10CrMoAl钢的耐腐的蚀原因及机理。方法通过对10CrMoAl钢进行盐雾试验(72、168、240 h)来模拟其海水腐蚀,并对试验后的试样进行了腐蚀速率、SEM、能谱、XRD及电化学分析及研究。结果 72、168、240 h盐雾腐蚀周期下,试样的腐蚀速率分别为2.352、1.915、2.218 mm/a。72 h盐雾腐蚀试验后,Cr和Mo主要在靠近基体一侧富集;168 h盐雾腐蚀试验后,Cr主要在靠近外表面的锈层处偏聚严重;240 h盐雾腐蚀试验后,在靠近锈层的基体一侧又出现了Cr和Mo的明显偏聚,并同时出现"白亮层"。随着腐蚀时间的延长,锈层中Fe Cr2O_4和γ-Fe_2O_3含量的变化趋势是一致的,即先不断上升,然后趋于稳定。结论随着腐蚀时间的延长,腐蚀速率先降低后升高再降低,最后趋于稳定。腐蚀过程是一个周而复始的循环过程:Cr和Mo在锈层与基体交界处不断富集—形成耐腐蚀层—腐蚀脱落—Cr和Mo在锈层与基体交界处富集。这种富集规律对防腐蚀有一定的作用。此外,Fe Cr2O_4在锈层中含量较多时,具有显著的防腐功能。

Comparative Analysis of Salt Spray Corrosion of 10CrMoAl Hot Rolled Sheet in Different Periods

The work aims to reveal cause and mechanism of corrosion resistance of 10CrMoAl steel. Seawater corrosion of 10CrMoAl steel was simulated by performing salt spray test (72 h, 168 h and 240 h). Corrosion rate, SEM, energy spectrum, XRD and electrochemical properties of the sample subject to test were analyzed and studied. After 72 h, 168 h and 240 h salt spray corrosion, the corrosion rate of the sample was 2.352 mm/a, 1.915 mm/a and 2.218 mm/a, respectively. After 72 h salt spray corrosion test, Cr and Mo were mainly enriched near the substrate; after 168 h salt spray corrosion test, Cr mainly congre-gated seriously on the rust layer close to outer surface; after the 240 h salt spray corrosion test, Cr and Mo congregated obvious-ly on the substrate near the rust layer again, and "white light layer" appeared simultaneously. As corrosion time prolongs, varia-tion trends of FeCr2O4 andγ-Fe2O3 content in the rust layer were consistent, that is, first rose continuously and then tended to be stabile. As corrosion time prolongs, corrosion rate first decreases and then increases, later decreases, and finally stabilizes. Enrichment law of Cr and Mo: first enrich at the junction of rust layer and substrate→corrosion resistant layer takes shape→corrosion layer peels off→Cr and Mo again enrich at the junction, this cycle goes round and round. This enrichment law has certain effect on corrosion prevention. In addition, FeCr2O4 exhibits significant corrosion resistance function when FeCr2O4 content is higher in rust layer.