Effect of electrochemical polishing on surface quality and corrosion resistance of Ti6Al4V crowns fabricated by selective laser melting

Abstract

The effects of electrolyte ratio, voltage, and polishing time on the surface quality and corrosion resistance of the Ti6Al4V crowns fabricated by selective laser melting were analyzed in this paper. The results show that, the surface roughness of the Ti6Al4V crowns is large, and there are a large number of powder particles on the sample surface. At the same time, the undulating molten pool boundary and steps can be observed and the initial roughness is about 30 μm. For the electrochemical polishing performed with the volume ratio of perchloric acid and acetic acid as 1:8, when the voltage is low (10 V), the adhered powder particles are removed, the surface roughness changes little, the polishing effect is not obvious. Meanwhile, when the voltage is high (50 V) or the volume ratio of perchloric acid and acetic acid is high, the surface is locally uneven, the surface roughness increases, the polishing effect is excessive. The surface quality of the Ti6Al4V crowns is significantly optimized by polishing in the electrolyte with the volume ratio of perchloric acid and acetic acid as 1:8 at 30 V for 30 min, the surface roughness is about 1 μm after polishing, satisfying the requirements for application. The corrosion resistance of the Ti6Al4V crowns after electrochemical polishing is greatly improved, which is nearly an order of magnitude compared with the crowns without the surface treatment.

Keywords

• selective laser melting
• titanium alloys
• crown
• electrochemical polishing
• roughness
• corrosion resistance