Electrochemical micromachining of micro-dimple arrays on the surface of Ti-6Al-4V with NaNO₃ electrolyte

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• 作者：Xiaolei Chen ; Ningsong Qu ; Zhibao Hou
• 关键词：Ti ; 6Al ; 4V ; Micro ; dimple array ; Electrochemical micromachining ; NaNO3 electrolyte ; PDMS mask ; Pulsed current
• 刊名：The International Journal of Advanced Manufacturing Technology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：88
• 期：1-4
• 页码：565-574
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Industrial and Production Engineering; Media Management; Mechanical Engineering; Computer-Aided Engineering (CAD, CAE) and Design;
• 出版者：Springer London
• ISSN：1433-3015
• 卷排序：88

文摘

Titanium alloys are widely used in the aerospace and biomedical industries. Micro-dimple arrays, as a kind of surface texture, have been applied on titanium alloy surfaces to enhance tribological behaviour as well as to affect the biological performance of titanium implants. Through-mask electrochemical micromachining (TMEMM) is a promising approach to generate micro-dimple arrays on metal surfaces. In general, sodium bromide and methanol–sulfuric acid, which could dissolve the passive oxide layer on titanium alloy surfaces, are used as electrolytes to generate micro-dimple arrays. However, these electrolytes are caustic, which can damage the equipment, and are unfavourable for industrial applications. In this paper, an environmentally friendly NaNO₃ electrolyte was employed to generate micro-dimple arrays on titanium alloy surfaces in TMEMM with a reusable mask; this made the process more efficient and safer. Experiments showed that there was serious stray corrosion on the titanium alloy surfaces when the micro-dimple arrays were generated using direct current. To obtain high-quality micro-dimple arrays, a pulsed current was employed in TMEMM. The results showed that machining parameters of applied voltage of 24 V, pulse duty cycle of 10 % and frequency of 100 Hz were appropriate to improve the machining quality. Micro-dimple arrays with no stray corrosion were thus generated. Moreover, the electrolyte temperature also influenced the machining accuracy, and a low electrolyte temperature of 20 °C was useful to reduce the undercutting of micro-dimples and improve machining localization. With the optimized parameters, micro-dimples with a diameter of 110 μm and depth of 20 μm were generated.