Q235扁钢接地材料杂散电流腐蚀行为研究

Stray current corrosion behavior of Q235 carbon steel grounding material

针对接地网服役过程中的杂散电流腐蚀问题,在模拟交、直流杂散电流干扰条件下,研究了Q235扁钢接地材料的腐蚀行为,利用扫描电镜(SEM)和X线衍射(XRD)等方法研究了材料的腐蚀形貌及腐蚀产物,分析了材料的电位、电流变化规律及腐蚀失重.结果表明:杂散电流腐蚀具有集中腐蚀特征,腐蚀产物层疏松多孔,有明显裂纹、分层、脱落现象,对基体不具有保护作用,腐蚀产物主要成分为Fe3O4和Fe2O3;失重测量结果显示,杂散电流存在时Q235扁钢腐蚀速率会大大增加,同等电流密度下,直流杂散电流腐蚀速率约为交流杂散电流的18倍;杂散电流腐蚀具有明显的电解腐蚀特征,电流流入金属构件部位成为阴极而受到保护,相反电流流出的部位成为阳极而受到腐蚀.

On the base of stray current corrosion （SCC） problems in the grounding grid service process,the corrosion behavior of Q235 carbon steel grounding material under simulation of AC or DC stray current interference conditions was studied by means of potential,current and corrosion weight loss measurement, and the corrosion morphology and products were characterized by SEM and XRD.The results showed that SCC had concentrated corrosion characteristics and the AC or DC SCC product layer was por- ous and had obvious crack,delamination and detachment,which implies its uselessness to protect the matrix.The corrosion products mainly consisted of Fe3O4 and Fe2O3.The results of weight loss measurement showed that the corrosion rate of Q235 steel was increased under AC or DC stay current interference conditions and the corrosion rate of DC SCC was about 18 times of AC SCC under the same current density.SCC had obvious electrolytic corrosion characteristics.The area where current flowing into was protected as the cathode and the current outflow area was corroded as the anode.