Chemical polishing of scaffolds made of Ti-6Al-7Nb alloy by additive manufacturing

The titanium-aluminium-niobium alloy is used in bone, dental and articular prosthetics, where high final surface quality is required. Bone scaffolds for tissue engineering require optimized cellular structures to provide pore diameters allowing the growth of osteoblasts. The aim of the presented paper is to estimate the quality of surface treatment of components with complex spatial structure, made of Ti-6Al-7Nb alloy by powder-bed selective laser melting (SLM), which is one of the additive manufacturing technologies for metal materials. Test pieces were subjected to chemical polishing to improve surface quality and remove loose powder particles trapped in the porous structure. It was found that resulting surface roughness and reduction of the number of non-melted powder particles on the scaffold surface are influenced mostly by chemical composition and concentration of the bath, as well as the method of medium delivery and exchange during the process. Further investigations were aimed at optimizing the process and increasing the number of work-pieces processed in a single lot.