铝型材表面斑点腐蚀的成因与对策分析

Analysis of Origination and Its Countermeasures on Surface Speckle Corrosion in Aluminum Extruded Profile

以6063铝型材为研究对象,采用模拟槽液,经SEM及EPMA等试验方法分析了表面斑点腐蚀的本质和发生机理,并给出了控制斑点腐蚀的措施。研究表明,斑点缺陷的实质是点蚀,它是由游离Si、FeSiAl等阴极相周围铝溶解而形成的表面缺陷,外部特征表现为部分带有残留物的腐蚀坑和部分无残留物的腐蚀坑。点蚀的发生与Si元素过剩及挤压工艺有关。

Origination and formation mechanism of surface speckle corrosion on the 6063 extruded profile were analyzed by analogue bath solution,SEM(scanning electron microscope)and EPMA,and its countermeasures were presented.The results show that speckle defects belong to spot erosion,which is formed from aluminum dissolution around cathode phase of free Si and FeSiAl,classified by surface defects.The appearance of the speckle exhibits erosion pit with residual phase and partial residual phase free,which is related to excessive Si element and extrusion process.