Atmospheric pressure plasma etching of Ti-6Al-4 V using SF6 etchant

Atmospheric pressure plasma (APP) etching has been developed recently into a manufacturing technique for silicon-based materials used for large optical lenses. However, there are few reports published regarding APP etching of non-silicon-based materials. We report here the development of an APP process using SF₆ for the etching of Ti-6Al-4 V metal alloy. Ti-6Al-4V is extensively used in aerospace and biomedical fields for its excellent properties; however, these properties also make it difficult to machine. Current techniques such as precision grinding and laser polishing can be slow, energy intensive, and cause damages and defects which reduce the lifetime of vital components. The results in this paper demonstrate effective material removal and little surface damage by APP etching of Ti-6Al-4V. Material removal rates between 0.5 and 2 mm³ min⁻¹ were obtained, and the proposed material removal mechanism is through the formation of volatile VF_x and TiF₄. These results show that APP etching is a promising technique for surface finishing of Ti-6Al-4V, particularly for large- and complex-shaped components.

Graphical Abstract