Influence of the Etching Time of Ti6Al4V Titanium Alloy with Selected Acid Solutions on Changes in Physical Parameters of the Element

Chemical surface treatment is one of the methods of finishing metals and their alloys.Chemical etching of surfaces is increasingly used for products manufactured using additive methods, also known as 3D printing.The article presents a method of finishing the surface of titanium alloy Ti6Al4V ELI elements produced traditionally using a bath in HF/HNO3 solutions.The influence of etching solutions on the surface quality and material loss was presented.As the etching time increased, the penetration of solutions into the surface increased, which resulted in an increase in the depth of the lowest profile recess (Rv parameter) relative to the height of the highest profile elevation (Rp parameter).The etching process affected the surface of the tested material, causing its hardness to decrease.The highest parameters of hardness decrease were obtained in a 3-minute etching process for B and C solutions.Extending etching to 15 minutes for individual solutions resulted in a varied effect, and in extreme cases, an increase in the surface hardness of the tested material.The obtained results showed a mass loss that was strictly dependent on time.