铝合金碱性电化学抛光新工艺

Technology for Electrochemical Polishing of Aluminum Alloy in Alkaline

为了克服碱性Brytal法抛光铝材的缺点,在NaOH溶液中加入EDTA作光亮剂抛光铝材,可获镜面光亮效果。其中直流抛光的工艺条件为:光亮剂25～40g/L、操作电压7V、电流密度20A/dm2、溶液温度45～50℃,抛光20min后铝材表面反射率为90%,阳极溶解损耗0.0182g/cm2;采用周期换向抛光时溶液温度可降低至40℃,阳极溶解损耗仅0.0101g/cm2。两抛光新工艺在生产成本、操作环境和抛光效果等方面均优于传统碱性电化学抛光。

EDTA was introduced as a brightener in NaOH solution for the electrochemical polishing of aluminium alloy, which was aiming at increasing the brightness of the polished Al alloy surface so as to overcome the disadvantages of aluminium polishing by alkaline Brytal method. It was found that the Al alloy surface electrochemically polished using the modified technology could be mirror-like bright, and both the modified direct current-based and periodic reversing-based technologies were superior to the conventional alkaline electrochemical polishing technology in terms of the cost, operation environment, and polishing effect. With respect to the optimum electrochemical polishing technology based on direct current, it was suggested to perform the polishing of the Al alloy at a concentration of EDTA brightener of 25~40 g/L, operating voltage of 7 V, current density of 20 A/dm 2, and polishing solution temperature of 45 ℃. The surface reflectivity of the resulting polished Al alloy was as high as 90% and the dissolving loss after 20 min polishing was as small as 0.0182 g/dm 2. At the same time, when cyclic reversing polishing process was used, the temperature of the polishing solution could be lowered to 40 ℃ and the dissolving loss of Al alloy in this case was as small as 0.010 1 g/cm 2.