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为研究喷砂酸蚀表面改性方法中酸蚀时间对喷砂后TC4钛合金表面形貌和抗腐蚀性的影响,采用220目的Al_2O_3颗粒对钛合金表面进行喷砂处理,然后对喷砂后的样品在HCl/H_2SO_4混合酸液中分别酸蚀不同的时间(0.5、1、2、3 h),并以抛光组为对照。通过扫描电子显微镜(scanning electron microscopy,SEM)和3D共聚焦显微镜对各组钛片的表面形貌进行表征和表面粗糙度测量。然后运用电化学工作站对各组样品进行耐腐蚀性试验,以评价各组样品的腐蚀行为。试验结果表明,随酸蚀时间的延长,钛合金表面形貌由杂乱趋于均匀化,粗糙度呈现先升后降趋势。2 h时粗糙度达到峰值,表面微孔比例最高,界面扩展面积比达222%。在抗腐蚀性能方面,所有喷砂酸蚀组抗腐蚀性均优于抛光组,表明喷砂酸蚀处理有助于生成腐蚀保护作用更强的氧化膜,且随时间延长,腐蚀倾向减小,3 h时最优。
In order to study the influence of acid etching time on surface morphology and corrosion resistance of TC4 titanium alloy after sandblasting, the surface of titanium alloy with 220 mesh was sandblasted by using 220 mesh Al 2 O 3 particles, The samples were etched for different times (0.5, 1, 2, 3 h) respectively in HCl / H 2 SO 4 mixed acid solution, and polished group was used as control. The surface morphology of each group of titanium films was characterized and the surface roughness was measured by scanning electron microscopy (SEM) and 3D confocal microscope. Then the electrochemical workstation was used to test the corrosion resistance of each sample to evaluate the corrosion behavior of each sample. The experimental results show that the morphology of the titanium alloy tends to be homogenized by the disorder with the time of etching, and the roughness of the titanium alloy increases first and then decreases. The roughness peaked at 2 h, with the highest proportion of micropores on the surface and the ratio of interface expansion to 222%. In terms of corrosion resistance, the corrosion resistance of all the sandblasting and etching groups is better than that of the polishing group, indicating that the sandblasting and acid etching treatment can help to form the oxide film with stronger corrosion protection effect, and the erosion tendency is reduced with time, Optimal at 3 h.