汽车强化腐蚀试验工况下热轧钢板的腐蚀行为

Corrosion Behavior of Hot Rolled Steel Plate under Enhanced Corrosion Test for Automobile

研究了热轧钢板(SPHC)在汽车强化腐蚀试验工况下的腐蚀行为,并采用扫描电镜(SEM)、能谱仪(EDS)、X-射线衍射仪(XRD)分析了SPHC钢经历7天、11天、19天试验后的腐蚀面的微观形貌、成分和物相。结果表明,在汽车强化腐蚀试验工况下,SPHC钢的腐蚀速率随着试验时间呈现非线性变化,当试验3~7天时,腐蚀速率先急剧增大,表面生成Fe2O3,此时为初期加速腐蚀;当试验到11天时,腐蚀速率开始下降到低点,腐蚀面生成Fe2O3和具有保护性的α-FeOOH,此时锈层较为致密,增强了SPHC钢的耐蚀性;当试验到14天时,腐蚀速率开始呈现上升的趋势,SPHC钢表面生成Fe2O3、微量的α-FeOOH和Fe3O4等腐蚀产物,此时锈层剥落,腐蚀更为严重。

The corrosion behavior of hot rolled steel plate(SPHC)under enhanced corrosion test condition of automobile was studied.The morphology,composition and phase of corroded surface of SPHC steel after 7,11 and 19 days of test were analyzed by Scanning Electron Microscopy(SEM),Energy Dispersive Spectrometer(EDS)and X-Ray Diffractometer(XRD).The results show that the corrosion rate of SPHC presents a nonlinear change with the test time under the enhanced corrosion test condition of automobile.When the test was from 3 to 7 days,the corrosion rate increased sharply first,and Fe2O3 was formed on the surface,which accelerated the initial corrosion.When the test reached the 11th day,the corrosion rate began to drop to a low point,Fe2O3 and protectiveα-FeOOH were formed on the etched surface.At this time,the rust layer was relatively dense,which enhanced the corrosion resistance of SPHC.When the test reached the 14th days,the corrosion rate began to show an upward trend,the corrosion products such as Fe2O3,trace amounts ofα-FeOOH and Fe3O4 were generated on the surface of SPHC.At this time,the rust layer was peeling off and the corrosion was more serious.