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针对输水条件下内衬矿渣-水泥砂浆球墨铸铁管的腐蚀问题,设计制作了内衬矿渣-水泥砂浆球墨铸铁管环试件,开展了扰动普通纯净水和6 mol/L氯化铵溶液腐蚀过程中内衬矿渣-水泥砂浆球墨铸铁管环试件的线性极化(LPR)和电化学阻抗谱(EIS)测试,分析了两种腐蚀溶液中试件的极化电阻、腐蚀电流密度和双电层电容等电化学参数随腐蚀时间的变化规律,并评估了试件的腐蚀程度。结果表明,在120 d的腐蚀时间内,普通纯净水中的矿渣-水泥砂浆球墨铸铁管环试件砂浆层电阻和球墨铸铁表面电荷转移电阻降低幅度很小,且腐蚀电流密度未达到钝化膜脱钝临界值,试件的腐蚀程度较小;而6 mol/L氯化铵溶液中,试件砂浆层电阻和球墨铸铁表面电荷转移电阻均明显降低,其腐蚀电流密度远超过钝化膜脱钝临界值,试件腐蚀程度严重;此外,运用LPR和EIS这两种测试方法所评估的腐蚀程度一致。
Aiming at the corrosion problem of lined slag-cement mortar ductile iron pipe under the condition of water conveyance, a lined slag-cement mortar ductile iron pipe ring specimen was designed and manufactured. The disturbance of common pure water and 6 mol / L ammonium chloride solution The linear polarization (LPR) and electrochemical impedance spectroscopy (EIS) measurements of lined slag-cement mortar ductile iron pipe ring specimens were carried out. The polarization resistance, corrosion current density and Electric layer capacitance and other electrochemical parameters with the variation of corrosion time, and assess the corrosion of the specimen. The results show that the erosion resistance of ductile cast ductile cast iron pipe ring specimen in ordinary pure water is very low and the corrosion current density does not reach the passive film during the 120 d corrosion time In the 6 mol / L ammonium chloride solution, the resistance of the mortar layer and the surface charge transfer resistance of the ductile iron were significantly decreased, and the corrosion current density far exceeded that of the passivation film Critical values, the specimen corrosion severity; In addition, the use of LPR and EIS these two test methods to assess the extent of corrosion consistent.