Assessment of the Functional Properties of 316L Steel Alloy Subjected to Ion Implantation Used in Biotribological Systems

Abstract

Clinical trials conducted in many centres worldwide indicate that, despite advances made in the use of biomaterials for medical applications, tribocorrosive wear remains a significant issue. The release of wear residue into body fluids can cause inflammation and, as a result, implant failure. Surface modification is one of the methods used to improve the mechanical, tribological, and fatigue properties of biomaterials. In this article, the authors investigated the impact of ion implantation on improving the functional properties of implant surfaces. This paper presents morphology, geometric surface structure, hardness, and tribological test results for layers obtained by ion implantation with nitrogen and oxygen ions on alloy 316L. The surface morphology and thickness of the implanted layer were examined using scanning microscopy. Atomic force microscopy was used to evaluate the geometric structure of the surface. Instrumented indentation was used to measure nanohardness. Model tribo tests were carried out for reciprocating motion under conditions of dry friction and lubricated friction with Ringer’s solution. The tribological tests showed that the implanted samples had a lower wear than the reference samples. Nitrogen ion implantation increased the hardness of 316L steel by about 45% and increased it by about 15% when oxygen ions were used.

Surface Characterization and Performance Evaluation of Nitrogen Implanted Coinage Dies

“…The Monte Carlo code SRIM2013 [17] was used to simulate the transport of 14 N in steel. The simulation outputs included the 14 N projected range (R p ) and corresponding straggling (∆R p ), the sputtering yield (S), and the fraction of backscattered 14 N ions (BS). These values were used to calculate the implanted profile according to the implanted versus sputtered balance equation [18]:…”

“…High fluence ion implantation of nitrogen ions is a well known and effective solution for enhancing the lifetime and improving the performance of many types of tools for which wear, friction, fatigue and corrosion problems are present [3][4][5][6][7][8][9][10][11][12][13][14][15]. For instance, Iwaki [3] implanted 14 N + ions (implantation energy = 75 keV, nominal fluences = 3.0 × 10 17 , 5.0 × 10 17 and 1.0 × 10 18 at/cm 2 ) on AISI H13 and AISI H13 prehardened steel samples.…”

“…After the nitrogen implantations, the friction coefficient decreased and the wear resistance improved. Wang et al [4] implanted 9Cr18 steel samples at room temperature (RT) with 14 N + ions (implantation energy = 100 keV, nominal fluence = 3.0 × 10 17 at/cm 2 ), which led to enhanced abrasion wear properties and improved chemical corrosion resistance after nitrogen implantation. Dryzek et al [5] observed that austenitic stainless steel (X10CrNiTi189) after 14 N + implantations (implantation energy = 100 keV, nominal fluences = 3.0 × 10 17 and 8.0 × 10 17 at/cm 2 ) followed by annealing (T < 320 • C) presented beneficial effects on microhardness and wear resistance, but no reduction of the friction coefficient was observed.…”

“…Dryzek et al [5] observed that austenitic stainless steel (X10CrNiTi189) after 14 N + implantations (implantation energy = 100 keV, nominal fluences = 3.0 × 10 17 and 8.0 × 10 17 at/cm 2 ) followed by annealing (T < 320 • C) presented beneficial effects on microhardness and wear resistance, but no reduction of the friction coefficient was observed. In turn, Bredell and Malherbe [6] studied tool steel samples implanted with 100 keV 14 N + ions at liquid nitrogen (LN2) temperature to nominal fluences of 3.0 × 10 17 and 1.0 × 10 18 at/cm 2 . The thickness of the implanted layer was determined from several depth profiles obtained using Auger electron spectroscopy (AES) combined with argon sputtering.…”

“…Two very recent papers also address nitrogen implantation in steel. Piotrowska et al [14] studied RT 14 N + ion implantation (implantation energy = 35 keV, nominal fluence = 5.0 × 10 17 at/cm 2 ) on 3162 steel alloy. The authors observed a 45% increase in hardness after nitrogen implantation and a 17% drop in the friction coefficient.…”