In this research, the influence of the N+ ion implantation process on the microstructure of a biodegradable Zn0.8Mg-0.2Sr alloy was investigated using various experimental techniques. Microscopic analysis revealed that a fluence of 17 & sdot;1017 ions/cm2 resulted in the oversaturation of pure Zn and Mg2Zn11 surfaces, leading to the formation of nano/micro-porous layers up to 400 nm thick. The behavior of the Zn-0.8Mg-0.2Sr alloy was observed to be similar to that of the individual pure phases, albeit without the creation of open pore structures. A limited formation of MgO and Mg3N2 was observed on the alloy surface, although the overall surface presence of Mg significantly increased from 0.8 to 15 wt. %. This increase was caused by the decomposition of the Mg2Zn11 phase during the process and the subsequent diffusion of Mg toward the surface. The absence of Zn3N2 within the samples could be explained by the thermodynamic instability and low Zn-N affinity. Despite the absence of zinc nitride, GD-OES confirmed 10 at. % of nitrogen in the pure zinc, suggesting a possible accommodation of N atoms in the interstitial positions. This study points to the complex nature of the process and highlights other promising directions for future research.

Titanium layers doped with biogenic elements attract much attention due to their ability to enhance the biological integration of implant materials.However, the addition of biogenic elements to the coating/layer changes its composition, structure, properties, and surface morphology, which affects their application possibilities.Therefore, the research and surface characterization of such layers is needed.In the present work, the mixed titanium layers with calcium and phosphorus have been synthesized by a dual electron beam evaporation method.The effect of doping in these mixed-titanium layers on their surface morphology and mechanical properties has been investigated.Atomic force microscopy was used for morphological characterization and nanoindentation was used to measure the mechanical properties (indentation hardness and reduced modulus).The surface layers are characterized in connection by tuning the deposition conditions and increasing dopant content.

The effect of adding calcium on the microstructural evolution and properties of the Ti-Ca-O system has been investigated. Calcium-doped titanium (Ti-Ca) thin films were prepared by dual electron beam deposition with the assistance of an oxygen ion beam. The films were characterized by glow discharge optical emission spectroscopy (GD-OES), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), to determine the elemental composition, chemical bonds and crystallinity. Oxygen ion assistance produces non-completely oxidized Ti-Ca films. The addition of calcium led to increased formation and stabilization of titanium oxides in the titanium matrix under conditions of oxygen deficiency. Replacement of Ti by Ca in TiO and TiO2 was observed, rather than the formation of a CaO and TiCaO mixture. Compound formation, crystallite growth and lattice expansion with rising Ca concentration induced an increase in mechanical properties (hardness and reduced elastic modulus) and surface roughness. High Ca concentration (5 at%) led to a significant reduction in mechanical properties, and above 1 at% led to a significant reduction in adhesion strength. The Ti-Ca films showed hydrophobic behaviour. The water contact angle followed the increasing trend of Ca concentration and surface roughness. There is a discussion of the changes in the studied properties.

An in situ investigation has been carried out by X-ray diffraction of the evolution of the crystallite size and the microstrain of low-temperature annealed commercially pure titanium grade 2 in the state after machining and polishing. Annealing was performed in vacuum at a temperature of 300, 400 and 500 degrees C, with various dwell times. The results presented here demonstrate that annealing temperatures lead to a significant reduction in microstrain and enhanced crystallite growth. The effect of the dwell time is more pronounced at temperatures above 400 degrees C. The dwell time at a temperature of 300 degrees C affects the crystallite growth but produces no microstrain relaxation. The presented results can be very useful for optimizing the working cycle and cooling during surface modification of titanium or exposed machines parts in order to improve the stability of the microstructure and extend the lifetime of components.

The impact of four pre-treatment techniques on the surface morphology and chemistry, residual stress, mechanical properties, corrosion resistance in a physiological saline solution and cell colonization of commercially pure titanium is examined in detail. Mechanical polishing, electrochemical etching, chemical etching in Kroll's reagent, and ion sputter etching with argon ions were applied. Surface morphologies reflect the nature of surface layer removal. Significant roughening of the surface and a characteristic microtopology become apparent as a result of the sensitivity of chemical and ion sputter etching to the grain orientation. The hardness in the near surface region was controlled by the amount of residual stress. Etching of the stressed surface layer led to a reduction in residual stress and surface hardness. A compact passivation layer composed of TiO, TiO2 and Ti2O3 native oxides imparted high corrosion resistance to the surface after mechanical polishing, chemical and electrochemical etching. The ion sputter etched surface showed substantially reduced corrosion resistance, where the corrosion process was controlled by electron transfer. The specific topology affected the adhesion of the cell to the surface rather than the cell area coverage. The cell area coverage increased with the corrosion stability of the surface.

Surface integrity plays a key role in the surface modifications and coating processes that provide high and long-term performance of the treated components. Argon ion bombardment is widely used in many surface modification processes and for surface pre-treatment. The effect of argon sputter cleaning on the residual stress, hardness and surface morphology of commercially pure titanium is investigated in this work. Titanium samples were mechanically polished and then etched by argon ions. The thickness of the sputtered layer was measured by a quartz thickness monitor. The hardness was investigated by nanoindentation, the residual stress was measured by X-ray diffraction, and the surface morphology was monitored by atomic force microscopy. Removal of the surface layer by argon ion bombardment caused a decrease in residual stress and a decrease in hardness. Uneven sputtering of grains resulted in increased surface roughness. The observed changes in surface properties increased with increasing thickness of the removed layer.

Nitrogen implantation into titanium and its alloys significantly improves their surface hardness, sliding behaviour, wear and corrosion resistance. A thin surface nanolayer originating, e.g., from air exposure or from condensation of oil vapours modifies the ion energy distribution and causes a difference in the ion range. The effect of the thickness of the contaminant carbon layer on the nitrogen distribution was investigated. Titanium samples with a carbon nanolayer were implanted with nitrogen ions. An almost Gaussian experimental concentration profile was observed. The maximum of nitrogen concentration moves into the specimen with increasing thickness of the nanolayer. The experimental findings are in agreement with the theoretical calculations. These results can be useful for optimizing surface modifications of titanium materials by ion implantation.

This paper presents the tribomechanical test results of Ti6Al4V alloy modified by carbon-based nanolayers with a thickness of 20 nm and 40 nm, prepared by nitrogen ion beam assisted deposition. The presence of carbon and nitrogen compounds was observed in the modified surface after ion bombardment. Nonstoichiometric TiNx was mainly detected near the interface nanolayer/titanium substrate and in the substrate itself. Ion bombardment led to an improved surface hardness of ~13 GPa in comparison to unmodified Ti6Al4V titanium alloy (~5.5 GPa) and alloy coated by carbon nanolayer without nitrogen ion assistance (~7 GPa). The decreasing of friction coefficient was achieved from 0.5–0.6 for untreated Ti6Al4V alloy to 0.1 for treated Ti6Al4V alloy. Wear testing using a joint wear simulator proved that the modified Ti6Al4V alloy has a higher resistance compared to the unmodified Ti6Al4V alloy. The primary local wear fault of the treated surface was observed after 240,000 cycles in comparison to enormous wear on the untreated surface after just 10,000 cycles. Treating the Ti6Al4V load-bearing components of implants with carbon-based nanolayers assisted by nitrogen ions is very promising in terms of extending the lifetime of implants and thereby reduces patient burden.

Carbon-based nanolayers have been attracting much attention due to their excellent low-friction properties, their high hardness and their good wear resistance. In this work we present the results of material research aimed at reducing the friction of the functional surfaces of titanium implants, and thus extending their lifetime to reoperation. Nitrogen ion beam assisted deposition of a carbon-based nanolayer was applied to modify the surface properties (i. e. sliding and wear) of Ti6Al4V biomedical titanium alloy. Ion bombardment caused structural changes, which led to an increase in surface hardness by a factor of 1.86 in comparison with a surface modified by a carbon nanolayer without nitrogen ion bombardment. An analysis of the chemical composition showed that the modified surface is composed of a carbon-based nanolayer, a mixed interface, and a nitrogen-enriched sublayer. Raman spectroscopy showed the DLC character of the carbon-based nanolayer with sp2 rich bonds. A TiN compound was detected by X-ray diffraction in the modified surface area. A very low friction coefficient below 0.1 was maintained for a normal load of 2N. The sliding behavior of the head (Ti6Al4V) and the shell (PEEK) tested on a joint wear simulator showed that surface modification of the head of the implant under optimized deposition conditions provides protection for the functional surfaces, leading to a reduction in wear and a substantial increase in lifetime.

Titanium and its alloys attract much attention due to their low specific weight, good corrosion resistance, high toughness, high yield strength and efficient biocompatibility. However, these materials have poor wear resistance, high friction and low hardness. Therefore, the surface properties often need to be modified. In the present work, nitrogen ion implantation was used to modify the titanium surface. Nitrogen doped layer integrated into the surface of titanium were investigated by several methods aimed primarily at determination of chemical composition, surface microstructure, surface mechanical properties and coefficient of friction. The present study includes results of Secondary Ion Mass Spectrometry, X-ray diffraction and nanoindentation.

The impact of the thickness of the carbon nanolayer on the depth distribution of the implanted nitrogen was examined. Ti6Al4V samples with a carbon nanolayer (20 and 40nm) were implanted with nitrogen with fluence of 1.2·1017cm−2 and an accelerating voltage of 90kV. GD-OES measurements showed an almost Gaussian-like nitrogen depth profile. The nitrogen peak moves deeper into the sample with increasing thickness of the nanolayer. The experimental depth profiles are in good agreement with the calculated results from the analytical model and from the SRIM2013 code.

A functionalized surface nanolayer less than 200 nm in thickness was prepared by nitrogen ion implantation at fluences of 2·1017, 4·1017, and 6·1017 cm-2 and at an accelerating voltage of 90 kV on the Ti6Al4V alloy. The evolution of the surface mechanical properties and the structural mechanism of the hardening were investigated. X-ray diffraction showed a great number of αTi+N interstitial nitrogen atoms and finely dispersed TiN precipitates in the modified surface nanolayer. The functionalized surface nanolayer on the sample with applied fluence of 2·1017 cm-2 had a predominant amount of αTi+N of about 45 wt% with minority TiN compound up to 20 wt%. The TiN content increased dramatically with increasing fluence of the implanted nitrogen. Nanoindentation investigations found that the indentation hardness improved up to 408% and that the reduced elastic modulus was increased up to 140%. The main hardening mechanism varied with the nitrogen concentration. Nitrogen ion implantation at low fluence of 2·1017 cm-2 led to a functionalized surface nanolayer in which the hardening was mainly caused by the microstrain due to the large amount of interstitially located nitrogen. Applied fluences of 4·1017 and 6·1017 cm-2 increased the content of TiN compounds, which became the predominant hardening mechanism.

It is well known that carbon-based materials have large variance in hardness. There are several methods for modifying the properties and improving the hardness of carbon-based layers. We applied ion beam assisted deposition for preparing a-C:N nanolayers on Ti6Al4V alloy. A Hysitron TI 950 TriboIndenter (TM) nanomechanical test instrument was used to assess the depth profiles of the mechanical properties on modified titanium substrates. Two methods were employed in the measurements: a) quasistatic partial unload, and b) dynamic Continuous Measurement of X (CMX). We obtained comparable results from both methods. The average nanoindentation hardness increased from HIT similar to 5GPa for a reference sample to HIT similar to 8.6 GPa for a sample coated by an a-C nanolayer, and to HIT similar to 11.5 GPa for a sample coated by an a-C:N nanolayer. The average storage modulus of the sample coated by a-C:N increased from E' similar to 130 GPa (reference sample) to E' similar to 155 GPa. The storage modulus of the sample coated by the a-C nanolayer was less than the storage modulus of the titanium substrate.