论文部分内容阅读
采用金属型铸造了3种成分的梯形高电位Mg-Mn牺牲阳极。通过模拟土壤环境中[饱和CaSO4-Mg(OH)2溶液]的恒电流腐蚀试验,研究了Mg-Mn牺牲阳极的腐蚀行为。结果表明,Mg-Mn牺牲阳极中杂质元素存在较大的溶质偏析和明显的晶粒尺寸差异,导致距离模具表面不同距离处的电流效率不同。杂质元素在晶界上不均匀分布,使Mg-Mn阳极产生晶间腐蚀,第二相粒子不均匀程度越大,未腐蚀部分机械剥落越严重,从而加大阳极的质量损失,降低了阳极的电流效率。腐蚀形貌观察发现,当Mg阳极表面呈现出条状的蚀坑时,机械剥落现象严重,腐蚀很不均匀,电流效率较低,仅为41%;Mg阳极的表面蚀孔孔径越细小,分布越均匀,电流效率越高。
Three types of trapezoidal high potential Mg-Mn sacrificial anodes were cast using a metal mold. The corrosion behavior of Mg-Mn sacrificial anode was investigated by simulating the galvanostatic corrosion test of [saturated CaSO4-Mg (OH) 2 solution] in the soil environment. The results show that there is a large segregation of solute segregation and obvious grain size differences in the impurity elements in the Mg-Mn sacrificial anode, resulting in different current efficiencies at different distances from the mold surface. The impurity elements are unevenly distributed on the grain boundaries, resulting in intergranular corrosion of the Mg-Mn anode. The greater the non-uniform second-phase particles, the more severe the mechanical peeling of the non-corroded parts, thereby increasing the mass loss of the anode and the reduction of the anode Current efficiency. The observation of the corrosion morphology shows that the mechanical spalling is serious, the corrosion is very uneven, and the current efficiency is low, only 41%. When the surface of the Mg anode shows a stripe pit, the surface corrosion pore diameter of the Mg anode is smaller and the distribution is smaller The more uniform, the higher the current efficiency.