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通过在热镀锌合金化(GA)钢板上施加10%、20%、30%的单向拉伸应变量,得到了变形量不同的合金化镀层。用动电位极化法和电化学阻抗图谱法测得了不同变形量的合金化镀层在3.5%NaCl溶液中的腐蚀行为,用SEM观察了变形量不同的合金化镀层腐蚀前后的表面形貌。结果表明,合金化镀层的电化学阻抗随拉伸变形量的增大而变小,在拉伸的初始阶段阻抗值下降尤为明显,腐蚀电流是先减小后增大,说明GA镀层的变形量为10%时,镀层电容具有较高的保持电荷的能力。变形后的试样优先在裂纹内部发生点蚀,腐蚀深度和面积随形变量的增加而增大。当变形量达到30%时,镀层表面的裂纹已经增大到不具备优先发生腐蚀的尺寸。
Alloying coatings with different amounts of deformation were obtained by applying uniaxial tensile strains of 10%, 20% and 30% to hot-dip galvannealed (GA) steel sheets. The corrosion behavior of alloy coatings with different deformations in 3.5% NaCl solution was measured by potentiodynamic polarization and electrochemical impedance spectroscopy. The surface morphology before and after the alloy coating with different deformations was observed by SEM. The results show that the electrochemical impedance of the alloyed coating decreases with the increase of the tensile deformation, especially in the initial stage of the drawing. The corrosion current first decreases and then increases, indicating that the deformation of the GA coating At 10%, the plated capacitor has a high charge holding capacity. Deformation of the sample prior to the occurrence of pitting within the crack, corrosion depth and area increases with the deformation increases. When the amount of deformation reaches 30%, the crack on the coating surface has been increased to the size that does not have preferential corrosion.