Laser Surface Texturing and Electropolishing of CoCr and Ti6Al4V-ELI Alloys for Biomedical Applications

Abstract

The interplay between a prosthetic and tissue represents an important factor for the fixation of orthopedic implants. Laser texturing tests and electropolishing were performed on two materials used in the fabrication of medical devices, i.e., CoCr and Ti6Al4V-ELI alloys. The material surface was textured with a diode-pumped solid state (DPSS) laser and its effect on the surface quality and material modification, under different combinations of laser power and marking speed, were investigated. Our results indicate that an increment of energy per unit length causes an incremental trend in surface roughness parameters. Additionally, phase transformation on the surface of both alloys was achieved. Chemical analysis by energy dispersive X-ray spectrometer (EDX) shows the formation of (Co(Cr,Mo)) phase and the M23C6 precipitate on the CoCr surface; while quantitative analysis of the X-ray diffractometer (XRD) results demonstrates the oxidation of the Ti alloy with the formation of Ti2O and Ti6O from the reduction of the α-Ti phase. The behaviors were both related with an increase of the energy per unit length. Control of the final surface roughness was achieved by an electropolishing post-treatment, minimizing the as-treated values. After polishing, a reduction of surface roughness parameters was obtained in a range between 3% and 44%, while no changes in chemical composition or present phases were observed.

Surface characteristics of additively manufactured CoCr and Ti6Al4V dental alloys: The effects of carbon and gold thin film coatings, and alkali‐heat treatment

“…Various physical surface modification techniques applied on these alloys including airborne‐particle abrasion (Antanasova et al, 2020) and Nd:YAG laser texturing (Sandoval‐Robles et al, 2020) involve subtractive processes. On the other hand, a range of treatments, including plasma (Kang et al, 2020), acid (De Moura et al, 2022), alkali, both alkali‐acid (Costa Valente et al, 2021) treatments and heat treatment in nitrogen atmosphere (gas nitriding) (Zhao et al, 2021) are employed not only to alter the surface roughness but also to modify the surface composition and enhance wettability or surface energy (Jemat et al, 2015) through chemical means.…”

Electropolishing with Low Mass Loss for Additive Manufacturing of Ti6Al4V in Zinc Chloride-Urea Deep-Eutectic Solvent

“…Titanium alloys such as Ti6Al4V have been widely used in biomedical, aerospace and other fields due to their excellent corrosion resistance, high specific strength, good biocompatibility and other properties. [1][2][3] On one hand, titanium has poor thermal conductivity and readily adheres to tools during processing, hence traditional melt-casted titanium alloys tend to have poor surface quality after machining, and they are typically considered difficult materials to machine. 4 On the other hand, with increasing complexity of parts, although new additive manufacturing (AM) methods can achieve a "higher degree of freedom in the design" and rapid production, it is difficult to avoid the inherent shortcomings of "print" surface roughening, 5 which is ascribed to the formation of sticky powder remnants, the spheroidisation phenomenon, the surface step effect, and other complex influences on the solidification surface.…”