Effect of laser texturing pattern on Ti6Al4V tribocorrosion in a physiological solution

Marjetka Conradi,Damjan Klobčar,Aleksandra Kocijan,Tadeja Kosec,Bojan Podgornik,Janez Kovač

doi:10.1680/jsuin.21.00048

Abstract

Laser texturing is a process that alters a material’s surface properties by modifying its morphology, which can improve properties like adherence, wettability, thermal and electrical conductivity and friction. Here, the effect of laser texturing was studied on an alpha-beta titanium alloy (Ti6Al4V) biomedical material. Two types of patterned surfaces, cross-hatch with varying scan-line separations, Δx = 100, 180 and 280 µm and dimples of 200 µm size, were prepared on the surface of alpha-beta titanium alloy by laser technology. Prepared samples were characterised for their surface properties, such as corrosion, wear-induced corrosion, friction and wettability. Electrochemical and tribocorrosion properties in a physiological solution were studied on the samples with different texture densities of cross-hatch pattern and dimples and compared to the as-received alpha-beta titanium alloy surface. Corrosion rate decreased for laser-textured samples, especially for cross-hatch texture (down to 1 µm/year for Δx = 180 µm) when compared to the as-received alpha-beta titanium alloy surface due to the changed laser-induced surface film and wetting properties. Friction coefficient slightly decreased for all laser-textured surfaces, most noticeably for cross-hatch patterns, from 0.38 (as-received) down to 0.34 (Δx = 180 and 280 µm). The main contribution to total wear in physiological solution increased due to the mechanical wear, which is governed by the removal of the surface oxide layer induced by laser texturing.

Highlights

Titanium-based alloys are well-established materials in a variety of applications.[1]
As the durability of materials is mostly governed by the material surface rather than its bulk properties, surface modification technologies serve as suitable approaches to enhance the performance of alpha-beta titanium alloy in biomedical applications.[8,9,10,11]
An evaluation was done on the impact of surface morphology on the synergistic effect between the corrosion and the mechanical properties of the patterned alpha-beta titanium alloy in human body conditions

Summary

Introduction

Titanium-based alloys are well-established materials in a variety of applications.[1]. As the durability of materials is mostly governed by the material surface rather than its bulk properties, surface modification technologies serve as suitable approaches to enhance the performance of alpha-beta titanium alloy in biomedical applications.[8,9,10,11] Researchers have focused on improving the tribocorrosion properties by morphological modifications by way of mechanical,[12] chemical and physical paths,[8,9,12] or by the application of organic/inorganic coatings.[13,14,15] Of the abovementioned approaches, laser texturing has been acknowledged as a promising technique for surface (nano) structuring owing to its high accuracy and flexibility, short processing times, good processing control and environmentfriendly approach.[16,17] Laser texturing induces changes in the materials’ microstructures, resulting in an increased hardness and corrosion resistance.[7,18] it produces controllable periodic surface structures and thicker oxide layers.[19] The synergy of simultaneous surface pattern formation and oxidation enables preparation of surfaces with specific target properties with desirable roughness, wettability, topography manipulation from micro- to nanoscale, hardness and corrosion properties.[18,20] Such modified surface characteristics lead to the minimisation of the contact area, continuous lubrication due to the lubricant’s storage on the textured surface and the reduction of the abrasive wear due to the entrapment of wear debris.[4]

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Conclusion