输电杆塔用热镀锌钢在模拟东南沿海大气环境中的加速腐蚀试验方法研究

Study on Accelerated Corrosion Test Method of Hot-Dip Galvanized Steel for Transmission Tower in Simulated Southeast Coastal Atmospheric Environment

为探讨室内中性盐雾+周浸加速试验对热镀锌钢的加速性以及室外曝露试验与室内加速试验的相关性,通过腐蚀动力学、腐蚀产物宏观形貌、微观组织以及物相组成等方面的表征,研究了输电杆塔用热镀锌钢在室内中性盐雾+周浸加速试验与东南沿海地区高温高湿的大气环境室外曝露试验中的腐蚀行为。结果表明:相对于室外大气曝露试验,经过5个周期的中性盐雾+周浸试验,热镀锌钢平均腐蚀速率明显增大,腐蚀加速比为416.1,中性盐雾+周浸可以快速模拟热镀锌钢从服役到失效的过程;SEM和XRD结果表明室内加速试验后期形成Zn_(5)(OH)_(8)Cl_(2)·H_(2)O和NaZn_(4)(SO_(4))Cl(OH)_(6)·6H_(2)O复合腐蚀产物层,与室外曝露试验的腐蚀过程及腐蚀产物相近,腐蚀产物相对致密,能够起到进一步阻止基体金属被腐蚀的作用,室内中性盐雾+周浸加速腐蚀能够反映热镀锌钢在东南沿海地区室外大气环境的腐蚀过程。

To explore the acceleration of indoor neutral salt spray+peripheral immersion accelerated test on hot-dip galvanized steel for power transmission tower and the correlation between outdoor exposure test and indoor accelerated test,the corrosion behaviors of hot-dip galvanized steel for power transmission tower in indoor neutral salt spray+peripheral immersion accelerated corrosion test and outdoor atmospheric exposure test in a heat and humidity atmosphere in China’s southeastern coastal area were investigated by means of corrosion kinetics,macro morphology and microstructure of corrosion products,and phase composition.Results showed that compared with outdoor atmospheric exposure test,the average corrosion rate of hog-dip galvanized steel increased significantly after 5 cycles of indoor neutral salt+peripheral immersion test,and the corrosion acceleration ratio reached 416.1,which indicated that neutral salt spray+peripheral immersion could quickly simulate the process of hot-dip galvanized steel from service to failure.Meanwhile,SEM and XRD results displayed that the composite corrosion products mainly contained Zn_(5)(OH)_(8)Cl_(2)·H_(2)O and NaZn_(4)(SO_(4))Cl(OH)_(6)·6H_(2)O during later stage of indoor accelerated test.The corrosion process and corrosion products were similar to those in atmospheric exposure test.The corrosion products were relatively denser,and so they could protect the metal substrate from further corrosion.In general,this indoor neutral salt spray+peripheral immersion accelerated corrosion test could reflect the corrosion process of hot-dip galvanized steel served in outdoor atmospheric China’s southeast coastal area.