钛合金的环保电化学抛光工艺

Environment-friendly electropolishing of titanium alloys

针对航空用钛合金开发了一种不采用氢氟酸、甲醇、铬酐类等有毒物质的低毒、无刺激、环保型电化学抛光工艺,并采用光学显微镜、原子力显微镜等方法对电化学抛光后的钛合金表面形貌进行研究.该工艺所用溶液由无水乙醇、乳酸、高氯酸和高氯酸钠组成,将Ti-10V-2Fe-3Al钛合金在直流电源恒电流模式下电化学抛光,可以通过改变抛光时间、电流密度和高氯酸浓度等参数控制腐蚀深度.分别在体积分数为5%,10%和15%的三种高氯酸溶液中和在20,25和30 A·dm-2三个电流密度下进行电化学抛光.抛光后的钛合金表面形貌观察结果表明:在高氯酸含量较低(5%)的溶液中以20 A·dm-2电流密度抛光可以取得较理想的效果.

The titanium alloy surface was polished in a recently self-developed electrolyte. The morphology of the polished alloy surface was characterized by optical microscopy （OM） and atomic force microscopy （AFM）. The electrolyte was made of alcohol, lac- tic acid, perchloric acid and sodium perchlorate instead of those poisonous compositions such as hydrofluoric acid, methanol and chromate. The alloy surface was polished in the solutions containing perchloric acid of 5 96, 10 % and 15 % in volume fraction at different current densities of 20, 25 and 30 A·dm^-2, respectively. The corrosion rate was estimated by using weight loss method. The thickness of the removed surface layer was dependent upon polishing time, current density and the concentration of perchloric acid. It was shown that the 5 % perchloric acid and 20 A·dm^2 current density were good to electropolishing of the titanium alloy.