pH值对Q235钢在模拟土壤中腐蚀行为的影响

Effect of p H Value on Corrosion Behavior of Q235 Steel in an Artificial Soil

采用一种新型的土壤腐蚀评价方法——硅藻土模拟土壤实验室加速腐蚀法,进行了Q235钢在不同p H值模拟土壤腐蚀介质中的埋片20 d的腐蚀实验。结果表明:随着模拟土壤的p H值从4.5升高至8.5,Q235钢的腐蚀速率持续下降,这一规律与已有的实际土壤下的腐蚀规律相同,而试样表面由较严重的全面腐蚀转变为轻微的局部腐蚀;酸性模拟土壤条件与碱性条件下的腐蚀产物组成一致,主要是α-Fe OOH,Fe3O4,γ-Fe OOH和Fe2O3,但α-Fe OOH和Fe3O4含量差别大,碱性条件下腐蚀产物中Fe3O4的含量上升,α-Fe OOH的含量下降。

Coupons of the grounding material Q235 steel were buried in an artificial soil of diato- mite with different pH values for 20 d, and then the corrosion behavior of the steel was examined. The results indicated that the pH value of the artificial soil had a great effect on the corrosion be- havior of Q235 steel. With the increasing of pH value, the corrosion rate of the steel in the artificial soil decreased, which accorded fairly well with that in the actual soil, correspondingly the corro- sion type of the coupons turned from rather serious uniform corrosion to slight local corrosion. The corrosion products formed in acidic artificial soil are consistent with those in an alkaline artificial soil, they all composed mainly of a-FeOOH, Fe3O4, γ-FeOOH and Fe2O3, however the products in the late case contained higher FeaO4 and less a-FeOOH.