Dual Ion Implantation Research Articles

Ion Implantation Combined with Heat Treatment Enables Excellent Conductivity and Corrosion Resistance of Stainless Steel Bipolar Plates for Hydrogen Fuel Cells.

316 L stainless steel is an ideal bipolar plate material for a proton exchange membrane fuel cell (PEMFC). However, the thickening of the passivation film on the stainless steel surface and the dissolution of corrosive ions during operation will affect the durability of the PEMFC. Herein, a heterogeneous layer is prepared on the surface of 316 L stainless steel through dual ion implantation of molybdenum ion and carbon ion combined with heat treatment to promote the corrosion resistance and conductivity of the bipolar plate. The ion implantation technique resulted in a uniform distribution of Mo and C elements on the surface of 316 L stainless steel, with a modified layer depth of about 70-80 nm. The electrical conductivity of the ion implanted samples was significantly improved, and the interfacial contact resistance was reduced from 464.25 mΩ × cm2 to 42.49 mΩ × cm2. Heat treatment enhances the surface homogenization, repairs the defects of irradiation damage, and improves the corrosion resistance of stainless steel. The corrosion current density of (Mo+C)-600 samples decreased from 1.21 × 10-8 A/cm2 to 2.95 × 10-9 A/cm2 under the long-term corrosion condition of 4 h. These results can provide guidance for the modification of stainless steel bipolar plates.

Influence of dual Mo and Ru ion implantation on the characteristics of commercial TiN-TiAlN-coated WC-10wt%Co-0.5wt%Cr3C2 face milling inserts

The influence of simultaneous dual Mo + Ru ion implantation into commercial TiN and TiAlN hard metal coated WC-10wt%Co-0.5wt%Cr3C2 face milling inserts were investigated at dosages from 5 × 1015 to 1 × 1017 ions/cm2 at 100 keV acceleration voltage. Various characterisation techniques such as field emission scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy, glancing incident X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterise the microstructure and topography of the as-received and ion implanted samples. The micro-hardness and residual stresses were also determined. Face milling tests were conducted to determine the effect of ion implantation on the wear rate. It has been observed that the dual Mo + Ru ion implantation with a biased Mo content extended 1000 nm into the dual TiN/TiAlN layer with significantly improved microhardness and increased anisotropy between the σ11 and σ22 stress components of the substrate, indicative of related effects in the coatings. The strengthening effect of Ru was observed at all ion implantation dosages even though wt% of Ru was significantly lower than the wt% of Mo. There were no visible changes to the microstructure of the substrate, but the presence of Mo and MoO2 chemical phase contents were observed through XPS. All the ion implantation dosages improved machining performance as the wear rate of the ion implanted face milling inserts was lower than that of as-received TiN and TiAlN coated WC-10wt%Co-0.5wt%Cr3C2 face milling inserts.

Divacancy and silicon vacancy color centers in 4H-SiC fabricated by hydrogen and dual ions implantation and annealing

Silicon carbide (SiC), as a wide-band gap semiconductor, plays an important role in high temperature and high-power devices, and the spin defect has great application prospect in quantum technology. Divacancy in SiC (VCVSi, VV) has attracted more and more attention. There are a lot of experimental studies on color center preparation by ion implantation, but the mechanism of atomic scale defects in the experimental preparation process is not fully understood. EPI epitaxial 4H–SiC was implanted with 250 keV proton at room temperature under three fluence of 1E14 cm−2, 1E15 cm−2, 1E16 cm−2. Defects of implanted 4H–SiC samples were characterized by photoluminescence spectrum and electron paramagnetic resonance (EPR). The existence of the optimal implantation fluence for VSi and VCVSi (VV) color centers by hydrogen ion implantation was found. Molecular dynamics (MD) simulation by considering the ionization energy loss for swift ion implantation were used to study the defect distribution and transformation at atomic-scale during hydrogen ion implantation and post-annealing. The optimal implantation fluence was found and confirmed by comparing the atomic-scale implantation simulation with the experimental results. In the annealing simulation, the optimal annealing temperature for the color centers in 4H–SiC was verified, and its formation mechanism was analyzed by accurately calculating the defect transformation during the annealing process. Finally, in order to accurately control the depth of color center in 4H–SiC, dual ions implantation of carbon and proton has been studied to realize the optimal divacancy yield by SRIM and MD simulations. Molecular dynamics simulation results showed that low-fluence C pre-implantation is helpful to improve the color center yield for the dual ions implantation.

Molecular dynamics simulation of color centers in silicon carbide by helium and dual ion implantation and subsequent annealing

Atomic and close-to-atomic scale fabrication with high yield for the color centers in silicon carbide is critical in developing its applications. Combined with Wigner-Seitz method and identify diamond structure method to consider the structure around the silicon vacancy (VSi), it is found that He ion implantation is more likely to fabricate a small number of silicon vacancies with complete structure but locating deep, while Si ion implantation is more likely to introduce more silicon vacancies with incomplete structure but a large number and closer to the near surface. Therefore, a method of dual ion implantation is proposed in this paper. By adjusting the ratio of He to Si ion concentration for dual ion implantation, the fabrication yield of color centers with depth below 5 nm can be increased compared with that of He implantation after high temperature annealing. Molecular dynamics (MD) simulation is employed to discover the underlying mechanism of VSi color center and damage evolution by helium ion and dual ion implantation into four-hexagonal silicon carbide (4H–SiC) with subsequent annealing. Density-functional theory (DFT) calculation proves that magnetic-spin polarization enhances the stability of carbon anti-vacancy pair (CSiVC) defect, which indicates CSiVC defects are more stable than VSi defects. The evolution of the VSi color centers of different defect models are also calculated at various temperatures by MD, and the dynamic process of VSi defects to CSiVC defects is demonstrated. It is revealed that the decrease of the VSi color center at high temperature annealing is partly due to the transformation of some silicon vacancies to CSiVC defects.

A comprehensive study of the nonlinear optical response exhibited by ion-implanted silica plates with Au and Pt nanostructures

Third-order nonlinear optical properties exhibited by Platinum nanoclusters and Gold nanoparticles integrated in a two-stage configuration are reported. Comparative nanostructures were nucleated in a monolithic complex platform form based on a single matrix by a dual ion-implantation process and a reduction in the ablation threshold from 2.2 J/cm2 to 1.2 J/cm2 was obtained. This modification in the photothermal response exhibited by the nanoparticles seems to derive from a fractional transfer of energy. Femtosecond z-scan measurements at 800 nm revealed a strong two-photon absorption in the dual-implanted sample together to an ultrafast electronic nonlinearity responsible for a self-defocusing effect. These findings highlight the potential for tailoring quantum systems by integration of hybrid photonic circuits using multi-implantation processes.

Luminescence of ZnO nanocrystals in silica synthesized by dual (Zn, O) implantation and thermal annealing

Zinc blende ZnO nanocrystals (NCs) were synthesised in amorphous silica by high-fluence dual (Zn, O) ion implantation and subsequent thermal annealing in air. We observed the formation of core/shell nanoparticles at the depth of maximum Zn concentration as a result of an incomplete oxidation process. The silica matrix with ZnO NCs exhibits an intense white-greenish emission. Low-temperature photoluminescence spectroscopy revealed various radiative recombination mechanisms in the zinc blende ZnO NCs involving intrinsic defects that act as donors and acceptors.

Mo-doped, Cr-Doped, and Mo–Cr codoped TiO2 thin-film photocatalysts by comparative sol-gel spin coating and ion implantation

Uniformly codoped anatase TiO2 thin films of varying (equal) Mo and Cr concentrations (≤1.00 mol% for each dopant) were fabricated using sol-gel spin coating and deposited on fused silica substrates. All films were annealed at 450 °C for 2 h to recrystallise anatase. Undoped anatase films have been subjected to dual ion implantation for the first time, using Mo, Cr, and sequential Mo + Cr at 1 × 1014 atoms/cm2. The films were characterised by GAXRD, AFM, SIMS, XPS, and UV–Vis and the performance was assessed by dye degradation. Despite the volumetric doping by sol-gel and the directional doping by ion implantation, neither method resulted in homogeneous dopant distributions. Both methods caused decreasing crystallinities and associated partial amorphisation. The XPS signal of the uniformly codoped films is dominated by undissolved dopant ions, which is not the case for the ion-implanted films. Increasing Ti valences are attributed to the fully oxidised condition of the Ti4+ ions that diffuse to the surface from Ti vacancy formation compared to the Ti valence of the bulk lattice, which contains Ti3+. Increasing O valence is attributed to the electronegativity of O2−, which is higher than that of Ti4+. Detailed structural mechanisms for the solubility and energetics mechanisms involve the initial formation of Mo and Cr interstitials that fill the two voids adjacent to the central Ti ion in the TiO6 octahedron, followed by integrated solid solubility (ISS) and intervalence/multivalence charge transfer (IVCT/MVCT). The sequential order of the last two is reversed for the two different doping methods. These two effects are likely to be the source of synergy, if any, between the two dopant ions. The photocatalytic performances of the uniformly codoped films are relatively poor and correlate well with the band gap (Eg). The performances of the ion-implanted films do not correlate with the Eg, where TiO2–Mo performs poorly but TiO2–Cr and TiO2–Mo–Cr outperform the undoped film. These results are interpreted in terms of the competition between the effects of Mo doping, which causes partial amorphisation and/or blockage of active sites, and Cr doping, which may cause Mo–Cr synergism, Cr-based heterojunction formation, and/or improved charge-carrier separation owing to the surface-deposition nature of ion implantation.

In situ transmission electron microscopy with dual ion beam irradiation and implantation

To study the helium effects and their interactions with displacement damage in irradiated materials, an in situ dual-ion beam irradiation capability with transmission electron microscopy was recently established at the IVEM-Tandem Facility at Argonne National Laboratory. Pure nickel was irradiated in situ individually with 1 MeV Kr ions for displacement damage study, 16 keV He ions for helium implantation, and simultaneously with 1 MeV Kr ions and 16 keV He ions at the rate of 1 at.% He/dpa to study the interaction of helium and displacement damage at 500 °C. Helium bubbles were formed and segregated within dislocation loops during the He implantation experiment and no bubbles were observed outside the loops. The loop size increased with increasing helium concentration. In contrast, helium bubbles were formed uniformly in the matrix when nickel was irradiated simultaneously with 1 MeV Kr ions and 16 keV He ions. It is suggested that the uniformly-distributed defect clusters formed under 1 MeV Kr ion irradiation serve as trapping sites of helium atoms resulting in homogeneous nucleation of helium bubbles under the dual-ion beam irradiation in nickel.

Nanograins on Ti-25Nb-3Mo-2Sn-3Zr alloy facilitate fabricating biological surface through dual-ion implantation to concurrently modulate the osteogenic functions of mesenchymal stem cells and kill bacteria

Surface mechanical attrition treatment (SMAT) method is an effective way to generate nanograined (NG) surface on Ti-25Nb-3Mo-2Sn-3Zr (wt.%) (named as TLM), a kind of β-type titanium alloy, and the achieved nanocrystalline surface was proved to promote positive functions of osteoblastic cells. In this work, to further endow the NG TLM alloy with both good osteogenic and antibacterial properties, magnesium (Mg), silver (Ag) ion or both were introduced onto the NG TLM surface by ion implantation process, as a comparison, the Mg and Ag ions were also co-implanted onto coarsegrained (CG) TLM surface. The obtained results show that subsequent ion implantation does not remarkably induce the surface roughness and topography alteration of the SMAT-treated layers, and it also has little impact on the microstructure of the SMAT-derived β-Ti nanograins. In addition, the implanted Mg and Ag ions are observed to exist as MgO and metallic Ag nanoparticles (NPs) embedding tightly in the β-Ti matrix with grain size of about 15 and 7 nm, respectively. Initial cell adhesion and functions (including proliferation, osteo-differentiation and extracellular matrix mineralization) of rabbit bone marrow mesenchymal stem cells (rBMMSCs) and the bacterial colonization of Staphylococcus aureus (S. aureus) on the different surfaces were investigated. The in-vitro experimental results reveal that the Mg and Ag single-ion implanted NG surface either significantly promotes the rBMMSCs response or inhibits the growth of S. aureus, whereas the Mg/Ag co-implanted NG surface could concurrently enhance the rBMMSCs functions as well as inhibit the bacterial growth compared to the NG surface, and this efficacy is more pronounced as compared to the Mg/Ag co-implantation in the CG surface. The SMAT-achieved nanograins in the TLM surface layer are identified to not only play a leading role in determining the fate of rBMMSCs but also facilitate fabricating dual-functional surface with both good osteogenic and antibacterial activities through co-implantation of Mg and Ag ions. Our investigation provides a new strategy to develop high-performance Ti-based implants for clinical application.

Optical Properties of Silicon Nano-Structures: Metal Assisted Chemical Etching and a Two-Stage Ion Implantation

Two different methods of dual metal ion implantation technique and metal-assisted chemical etching are used to fabricate silicon nanostructures. Raman scattering and photoluminescence techniques have been employed to study the optical properties of formed Si nanostructures. Scanning Electron Microscopy images indicate the change in the surface morphology of Si nanowires with respect to the etching time. Dual ion implantation sample and metal-assisted chemical etching, prepared for 45 min exhibit similar optical properties. With a possible mechanism of their formation at room temperature, synthesizability of Si NWs in large scale for commercial purposes is discussed. It is expected that these Si NWs have got potential applications in optoelectronics, photonics and sensors.

Co-effects of C/Ag dual ion implantation on enhancing antibacterial ability and biocompatibility of silicone rubber

Although silicone implants are the most popular choice around the world for breast augmentation, reconstruction, and revision, due to the poor antibacterial properties and limited biocompatibility of silicone rubber (SR), one of the major complications, capsule contracture, is a lingering problem. To overcome the two main shortcomings, a dual ion implantation technique was applied to modify the surface of SR with the basic skeleton element of organic matter, carbon (C) and the broad-spectrum bactericide, silver (Ag). We present surface characterization, toxicological effects, and evaluation of the mechanical, antibacterial and biocompatible properties of C and Ag co-implanted SR (C/Ag−SRs). After ion implantation, surface roughness and tensile strength of these new materials increased. Biotoxicity was fully assessed by in vitro experiments on human fibroblasts and in vivo experiments on rats, showing that the low-Ag groups met safety standards. Both the anti-bacterial adhesion and bactericidal abilities of C/Ag−SRs were superior to those of SR, which had few antibacterial activities, especially against Staphylococcus epidermidis. With respect to biocompatibility, the adhesion of fibroblasts was promoted, while their proliferation was moderately inhibited on ion-implanted surfaces. After subcutaneous implantation in rats for 7, 30, 90 and 180 d, the capsular thickness around C/Ag−SRs was significantly lower than that around the SR. Additionally, there was no difference in the inflammatory reaction after 7 d of retention in vivo between C/Ag−SRs and SR. The results demonstrate that C/Ag−SRs are desirable shell materials for breast implants.

Periodic Surface Morphology Characteristics of Tungsten Under Simultaneous Helium and Deuterium Bombardment at 30 keV

The ITER divertor will feature tungsten monoblocks as the plasma-facing component (PFC) that will be subject to extreme temperature and radiation environments. This paper reports the development of surface morphologies on tungsten under helium bombardment at high temperatures, which has important implications for safety, retention, and PFC erosion. Polycrystalline tungsten samples were implanted in the Dual Advanced Ion Simultaneous Implantation Experiment dual-beam ion implantation experiment at the University of Wisconsin-Madison with He-only and simultaneous He-D implantation at incidence angles of 55 deg, ion energies of 30 keV, and surface temperatures of 900°C to 1100°C. Morphologies resulting from angled incidence conditions differed from those produced under normal incidence bombardment at similar energy and temperature conditions in previous work. A variety of ordered and disordered morphologies dependent on grain orientation were observed for fluences up to 6 × 1018 He cm−2. These morphologies displayed dependencies on crystal orientation at low fluences and incident beam directions at higher fluences. These structures appeared, with variation, under both single-species He and mixed He-D implantations.

The effect of different Fe concentrations on the structural and magnetic properties of near surface superparamagnetic Ni1−Fe nanoparticles in SiO2 made by dual low energy ion implantation

Abstract Structural and magnetic measurements were performed on SiO2 films containing near-surface Ni1−xFex superparamagnetic nanoparticles made by low energy ion implantation into SiO2 with the same Ni fluences of 2 × 1016 at./cm2 and two different Fe fluences so that x = 0.47 and x = 0.20. The x = 0.47 films had larger nanoparticles, a higher fraction of ordered moments in the nanoparticle cores, and thinner spin-disordered shells. The nanoparticle core spin-stiffnesses were slightly higher for x = 0.20 and smaller than that expected for bulk Ni1−xFex for both Fe concentrations. There was no evidence for magnetic dipole interactions between the nanoparticles that have been reported in compressed superparamagnetic ferromagnetic nanoparticles. dM/dH was estimated and found to be highest for x = 0.47 where it reached 15 at 300 K and 56 at 100 K. The measured dM/dH is consistent with that expected from a derivative of the Langevin function with negligible demagnetization where larger nanoparticles are expected to have a higher dM/dH.

Synergistic Effects of N/Cu Dual Ions Implantation on Stimulating Antibacterial Ability and Angiogenic Activity of Titanium.

Titanium and its alloys have been commonly used as implant materials. However, the inherent bioinert nature hinders its good osseointegration which limits its permanent clinical applications. In this work, nitrogen (N) and copper (Cu) dual ions were implanted into titanium by plasma immersion ion implantation and deposition (PIII&D) technology. The corrosion resistance, mechanical property, antibacterial ability, and angiogenic activity of the modified titanium surfaces were investigated. Experimental results show that titanium nitride (TiN) film embedded with Cu nanoparticles (Cu NPs) forms on the surface of the N/Cu dual ions implanted titanium. The N/Cu dual ions implanted titanium exhibits excellent corrosion resistance and mechanical property. The galvanic corrosion of Cu/TiN can effectively control copper ion release to enhance the antibacterial and angiogenic performances of the Ti surface.

Structural and magnetic properties of near surface superparamagnetic Ni1-xFex nanoparticles in SiO2 formed by low energy dual ion implantation with different fluences

Low energy implantation of Ni and Fe into SiO2 films resulted in the formation of superparamagnetic Ni1-xFex nanoparticles for Ni fluences of 2 × 1016 at./cm2, 4 × 1016 at./cm2, and 6 × 1016 at./cm2 where the Ni:Fe fluence ratios were 47:56, 53:47, and 63:37, respectively. Small ∼5 nm Ni1-xFex nanoparticles were dispersed in the implantation region for the lowest Ni fluence. Increasing the Ni fluence resulted in a different nanoparticle morphology where larger nanoparticles appeared at the surface and small Ni1-xFex segregated regions to a depth of ∼20 nm. The average nanoparticle size in the surface region was ∼8 nm for Ni fluences of 4 × 1016 at./cm2 and 6 × 1016 at./cm2. The highest Ni fluence film also had smaller Ni1-xFex nanoparticles at a depth of ∼11 nm. The largest high field moment per implanted ion was found for the intermediate Ni fluence. The spin-stiffness was similar for all fluences and smaller than that expected for bulk Ni1-xFex. A small spin-disordered region was evident with the same low spin-freezing temperatures that may be due to a similar spin-disordered shells. dM/dH at 300 K was estimated and found to be highest for a Ni fluence of 4 × 1016 at./cm2 where it reached 62.

Multiple ion beam irradiation for the study of radiation damage in materials

Abstract The effects of transmutation produced helium and hydrogen must be included in ion irradiation experiments to emulate the microstructure of reactor irradiated materials. Descriptions of the criteria and systems necessary for multiple ion beam irradiation are presented and validated experimentally. A calculation methodology was developed to quantify the spatial distribution, implantation depth and amount of energy-degraded and implanted light ions when using a thin foil rotating energy degrader during multi-ion beam irradiation. A dual ion implantation using 1.34 MeV Fe + ions and energy-degraded D + ions was conducted on single crystal silicon to benchmark the dosimetry used for multi-ion beam irradiations. Secondary Ion Mass Spectroscopy (SIMS) analysis showed good agreement with calculations of the peak implantation depth and the total amount of iron and deuterium implanted. The results establish the capability to quantify the ion fluence from both heavy ion beams and energy-degraded light ion beams for the purpose of using multi-ion beam irradiations to emulate reactor irradiated microstructures.

Tribological studies comparison between UHMWPE and PEEK for prosthesis application

This work reports on the tribological and surface hardness modifications of ultrahigh molecular weight polyethylene (UHMWPE) and polyether ether ketone (PEEK) after plasma immersion dual ion implantation of nitrogen, oxygen and helium ions at constant energy and fluence. The results show that the hardness and wear rate can be improved in both polymers by an appropriate combination of the bombarding ions. Wear tests were carried out on modified UHMWPE and PEEK against CoCrMo and Al2O3 counter materials, in an adult bovine serum (ABS) medium at 37°C. In particular, the dual bombardment with nitrogen and oxygen in a 3:1 ion fluence ratio provides the highest wear rate reduction on both polymers when sliding against CoCrMo. In the case of the test against Al2O3, the averaged low wear rates were obtained using He/N ion fluencies of 3:1. More specifically, the wear performance of plasma treated PEEK is superior to this shown by UHMWPE.

Synthesis of magnetic nanoparticles by low-energy dual ion implantation of iron and nickel into silicon dioxide followed by electron beam annealing

Magnetic nanoparticles have been made by low-energy dual ion implantation of iron and nickel into SiO2 with a nickel fluence ratio of 82% followed by electron beam annealing for 1800 s at 1000°C. After annealing, there is significant diffusion of iron and nickel into the silicon dioxide layer. Annealing also led to the formation of superparamagnetic nanoparticles with a narrow particle size distribution. The saturation moment at 5 K was 0.7 µB and a similar value was observed at 300 K, which indicates that the Curie temperature is far above room temperature. This moment is lower than that expected for Ni0.82Fe0.18. While the results clearly show the formation of superparamagnetic nanoparticles, it is not possible to determine whether nickel-iron, iron or nickel has formed.

Ni1−xFex nanoparticles made by low energy dual ion implantation into SiO2

Ni1−xFex nanoparticles were made by implanting Ni and Fe at 10 keV into a SiO2 film and electron beam annealing (EBA) with a Ni:Fe fluence ratio of 44:56. The as-implanted nanoparticles were superparamagnetic with average diameters of ∼4 nm. The high field moment followed Bloch’s T3/2 law where T is the temperature and there was a spin-glass component from disordered surface spins that was not previously reported for an implanted film with a Ni:Fe fluence ratio of 82:18 made under similar conditions. EBA led to non-spherical near surface Ni1−xFex nanoparticles with widths ranging from ∼60 nm to ∼220 nm where some of the nanoparticles were surrounded by a Fe1-z1Siz1Oz2 shell. Unlike the previous report on a 82:18 film, we do not find a bimodal particle size distribution with a significant fraction of smaller nanoparticles. The saturation moment is also less than that found in the bulk, which may be due to the Fe1-z1Siz1Oz2 shell that is antiferromagnetic or does not magnetically order. The saturation moment can be fitted to Bloch’s T3/2 law and a thin spin-disordered shell. Our results show that the Fe fraction in the ferromagnetic nanoparticles is less than the expected x = 0.56 and dual ion beam implantation and EBA with a Fe fluence fraction of between 0.56 and 0.18 could result in pure Ni1−xFex nanoparticles without excess Fe or a significant number of smaller nanoparticles.

Dual ions implantation of zirconium and nitrogen into magnesium alloys for enhanced corrosion resistance, antimicrobial activity and biocompatibility

Biodegradable magnesium-based alloys have shown great potential for medical applications due to their superior biological performances and mechanical properties. However, on one hand, some side effects including inferior biocompatibility, a local high-alkaline environment and gas cavities caused by a rapid corrosion rate, hinder their clinical application. On the other hand, it is also necessary to endow Mg alloys with antibacterial properties, which are crucial for clinic orthopedic applications. In this study, Zr and N ions are simultaneously implanted into AZ91 Mg alloys by plasma immersion ion implantation (PIII). A modified layer with a thickness of approximately 80nm is formed on the surface of AZ91 Mg alloys, and the hydrophobicity and roughness of these AZ91 Mg alloys obviously increase after Zr and N implantation. The in vitro evaluations including corrosion resistance tests, antimicrobial tests and cytocompatibility and alkaline phosphatase (ALP) activity tests, revealed that the dual ions implantation of Zr and N not only enhanced the corrosion resistance of the AZ91 Mg alloy but also provided better antimicrobial properties in vitro. Furthermore, the formation of biocompatible metal nitrides and metal oxides layer in the near surface of the Zr-N-implanted AZ91 Mg alloy provided a favorable implantation surface for cell adhesion and growth, which in return further promoted the bone formation in vivo. These promising results suggest that the Zr-N-implanted AZ91 Mg alloy shows potential for future application in the orthopedic field.