High-intensity Ion Implantation Research Articles

High-Intensity Titanium Ion Implantation into Aluminum under Conditions of Repetitively-Pulsed Energy Impact of a Beam on the Surface

High-Intensity Titanium Ion Implantation into Aluminum under Conditions of Repetitively-Pulsed Energy Impact of a Beam on the Surface

Features of titanium ion beams formation taking into account ion-electron emission realizing the synergy of high-intensity ion implantation and pulsed energy impact on the surface

In this work, we show the possibility of forming titanium ion beams of submillisecond durationin the average ion energy range from 20 to 60 keV with a maximum ion current densityof 3.3 A/cm2 at a pulsed power density of 132 kW/cm2 in individual pulses. The dependence of theion-electron emission coefficient on the average energy and current of the arc discharge is presented.It has been established that the ion-electron emission coefficient in the case of irradiation of a stainlesssteel target with a beam of titanium ions reaches a value of 1.6 at an average ion energy of 60 keV.The dependences of the radial distribution of the ion current density on the average ion energy areobtained for different positions of the collector relative to the geometric focus of the ballistic systemfor focusing the ion beam. Taking into account ion-electron emission, it has been experimentallyshown that with an increase in the average ion energy from 20 keV to 40 keV, an increase in the densityof the measured ion current is observed, while in the range from 40 to 60 keV, the ion current densitydecreases. Using nineteen collector sensors, it was shown that due to the influence of the partiallyuncompensated space charge of the ion beam, the best conditions for its focusing are achieved at adistance of 20 mm behind the geometric focus of the system.

Features of thermal processes and the influence of pulsed heating of surface layers of titanium on the diffusion transfer of dopants during high-intensity ion implantation

Methods for modification of surface and near-surface layers of materials and coatings by ion beamshave prospects for application in many fields of science and technology. The method of high-intensityimplantation by high-power density ion beams with submillisecond duration involves significantpulsed heating of the irradiated target’s surface layer, followed by its rapid cooling due to heatremoval into the material due to thermal conductivity and the implementation of repetitively-pulsedradiation-enhanced diffusion of atoms to depths significantly exceeding the projective ion range. Thispaper considers features of thermal processes and the effect of pulsed heating of near-surface titaniumlayers on diffusion transfer under conditions of synergy of high-intensity titanium ion implantationand energy impact of a high-power density repetitively-pulsed beam on the surface to increase iondoping depth due to radiation-enhanced diffusion under conditions of limited heating of the entiresample. The paper presents the data of numerical simulation of dynamic changes in temperature fieldsin titanium and titanium self-diffusion under the action of ion beams with a submillisecond durationand a pulse power of tens of kW/cm2 and fluence of ions in a pulse 1.25×1015 ion/cm2.

Study of the synergy effect of high-intensity aluminum ions implantation into titanium and energy impact on the surface

The work studies the synergy effect of high-intensity implantation of aluminum ions and thesubsequent impact of a powerful pulsed ion beam on the microstructure and properties of titanium.Specimens of titanium were implanted for one hour at a temperature of 1170 K with an ion fluenceof 1021 ions/cm2. Layers with a thickness of about 150 μm were obtained. The energy impact wascarried out by a powerful nanosecond pulsed ion beam with an ion current density on the targetof 100 A/cm2. The paper presents data on changes in the elemental composition, surface morphology,and microstructure of ion-doped and energy-modified layers. It has been established that the additionalenergy impact on the ion-doped layer of a powerful pulsed beam improves microstructure at depthsgreater than 3.4 μm. The synergistic of high-intensity ion implantation of aluminum and the energyimpact of a pulsed ion beam improves the wear resistance of titanium by eighteen folds.

Influence of Surface Sputtering during High-Intensity, Hot Ion Implantation on Deep Alloying of Martensitic Stainless Steel

This article is devoted to the study of the effect of ion sputtering on the alloy surface, using the example of martensitic stainless steel AISI 420 with ultrahigh-dose, high-intensity nitrogen ion implantation on the efficiency of accumulation and transformation of the depth distribution of dopants. Some patterns of change in the depth of ion doping depending on the target temperature in the range from 400 to 650 °C, current density from 55 to 250 mA/cm2, and ion fluence up to 4.5 × 1021 ion/cm2 are studied. It has been experimentally established that a decrease in the ion sputtering coefficient of the surface due to a decrease in the energy of nitrogen ions from 1600 to 350 eV, while maintaining the ion current density, ion irradiation fluence and temperature mode of target irradiation increases the ion-doped layer depth by more than three times from 25 μm to 65 µm. The efficient diffusion coefficient at an ion doping depth of 65 μm is many times greater than the data obtained when stainless steel is nitrided with an ion flux with a current density of about 2 mA/cm2.

Study of the influence of a powerful pulsed ion beam on titanium deeply-doped with aluminum

The work studies the synergy effect of high-intensity implantation of aluminum ions and the subsequent impact of a powerful pulsed ion beam on the microstructure and properties of titanium. Specimens of titanium were implanted for 1 h at a temperature of 1170 K with an ion fluence of 1021 ions/cm2. Layers with a thickness of about 150 μm were obtained. The energy impact was carried out by a powerful nanosecond pulsed ion beams with an ion current density on the target of 100 A/cm2. The paper presents data on changes in the elemental composition, and microstructure of ion-doped and energy-modified layers. It has been established that the additional energy impact on the ion-doped layer of a powerful pulsed beam improves microstructure at depths of about 4.31 μm. The synergistic of high-intensity ion implantation of aluminum and the energy impact of a pulsed ion beam improves the wear resistance of titanium by eighteen folds.

Numerical Simulation of Temperature Field Dynamics in Single-Crystal Silicon at Repetitively-Pulsed High-Intensity Ion Implantation and Energy Impact on the Surface Layer

Numerical Simulation of Temperature Field Dynamics in Single-Crystal Silicon at Repetitively-Pulsed High-Intensity Ion Implantation and Energy Impact on the Surface Layer

Simulation and experimental studies on the formation of high-power titanium ion beams for the synergy of ion implantation and energy impact on the surface

The development of a material modification method based on synergy of high-intensity ion implantation and simultaneous energy impact on the surface is aimed at creating deep ion-doped layers. To implement this method, the high power density of pulsed and repetitively-pulsed beams of metal and gas ions with micro-submillisecond duration are required. The paper presents the results of numerical simulation and experimental studies on the formation of pulsed high-intensity metal ion beams from vacuum arc plasma. The ballistic focusing of heavy ions at injection currents from 0.1 to 1 A has been studied. The influence of the ion current density, accelerating voltage, and conditions for neutralizing the beam space charge on the transport and focusing of a high power density ion beam has been studied. The possibility of ballistic formation of submillisecond titanium ion beams with a pulse power density of a hundred kilowatts per square centimeter has been experimentally shown.

Формирование мощных импульсных пучков ионов титана субмиллисекундной длительности из плазмы вакуумной дуги

The development of a method to improve performance properties of various materials, based on the synergy of high-intensity ion implantation and simultaneous energy impact on the surface, is aimed at creating deep ion-doped layers. Repetitively-pulsed high-power density beams of metal and gas ions with submillisecond duration are required to implement this method. This article presents the results of experimental studies on the forming pulsed high-intensity titanium ion beams from vacuum arc plasma. The effect on focusing and transport efficiency of the cell sizes of the grid focusing electrode in the form of a part of a sphere has been studied. The possibility of ballistic focusing of a titanium ion beam with a pulse duration from 150 to 500 μs with a power density of up to 100 kW/cm2 has been experimentally shown.

Modification of stainless steel based on synergistic of low-energy high-intensity ion implantation and high-current electron beam impact on the surface layer

The results of experiments on low-energy implantation of AISI 321 stainless steel by nitrogen ions are presented. The treatment was carried out by a pulsed beam of nitrogen ions obtained using a ballistic ion focusing system. The surface modification occurs with the formation of a two-layer structure, which is typical for ion-plasma nitriding processes of stainless steels. The thickness of the modified layer can reach 27 μm after 1 hour of ion-plasma treatment. The influence of subsequent modification of the ion-doped layer by the action on the surface of the pulsed high-current electron beam of microsecond duration is studied. The work presents the results of the studying the regularities of changes in the depth distribution of dopants, microstructure and phase composition of the modified and matrix layers by optical metallography, diffraction analysis and transmission electron microscopy.

Features of the Formation of Ultralow Energy High-Intensity Metal and Gaseous Ion Beams

This article studies the features and patterns of the formation of high-intensity beams of metal and gaseous ions of low and ultralow energy from dc vacuum arc and gas-discharge plasma. It presents the results of repetitively pulsed plasma immersion extraction of aluminum, titanium, and nitrogen ions from the plasma followed by the formation and transport of ion beam under conditions of its ballistic focusing. This article presents the experimental data on the influence of the grid focusing electrode cell sizes of 150 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$500~\mu \text{m}$ </tex-math></inline-formula> , the bias potential amplitude from 0.1 to 2 kV, the conditions for neutralizing the space charge of the beam during preliminary plasma injection into drift space and when using an additional thermoelectron source on the transport and focusing of ion beams. Here, it discusses the effect of the characteristic dimensions of the fine-structured grid and plasma parameters at ultralow bias potential amplitudes and the presence of significant initial energy in ions on the ion beam focusing. It was found that at bias potential amplitudes of 0.6 kV, it is possible to form repetitively pulsed ion beams with high current density reaching 170 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The obtaining of such beams opens up the possibility of implementing the method of high-intensity ion implantation under conditions of multiple decreases in the irradiated surface sputtering.

Special Aspects of High-Intensity Low-Energy Ion Implantation

Numerical simulations and experimental studies of surface and subsurface layers of different materials are performed in order to determine their real temperatures as a function of the regimes of high-intensity ion irradiation. The integral temperature of the target is measured using an electrically insulated thermocouple. A KLEIBER 740-LO high-temperature pulsed pyrometer is used to measure the dynamic variation of the local temperature. A contribution from the shock-wave mechanism into the mass transfer of the implanted impurity is studied during hot high-intensity ion implantation.

Microstructure of titanium alloy modified by high-intensity implantation of low- and high-energy aluminium ions

This study focuses on the analysis of microstructural, elemental and phase compositions of surface and near-surface layers of titanium after the implantation of aluminium. A titanium alloy with a chemical composition close to commercially pure titanium (grade 2) was used as the target material. Ion implantation was performed using two modes of irradiation: 1. repetitively pulsed ion beams with a mean ion energy of 35 keV; 2. low-energy-focused ion beams of high intensity with a mean ion energy of 2.6 keV. The irradiation fluence reached 1.1 × 1018 ion/cm2 using the first mode and 1.6 × 1021 ion/cm2 using the second mode. In both cases, the beam itself heated the targets. The peak concentration of aluminium after the implantation of medium-energy ions was ~65 at.%, and the maximum depth of dopant penetration was 2.6 μm. On the contrary, in the case of high-intensity low-energy ion implantation, the surface concentration of dopant reached a maximum of 25 at.%, but the depth of penetration increased significantly and achieved 50 μm. The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that fine-grained intermetallic phases, Ti3Al and TiAl, and solid solutions of various compositions were possibly formed after the medium-energy ion implantation. The mean grain size of the intermetallic phases was ~50 nm. XRD and TEM analyses in the case of low-energy high-intensity ion implantation demonstrated the formation of the ion-alloyed layer, which comprised intermetallic phase Ti3Al and solid solutions of aluminium in titanium. The grain size of Ti3Al phase can be 5 μm and more.

Temperature gradients in targets at low energy high-intensity ion implantation

This paper is devoted to the study of the gradient temperature field dynamics and distribution in the metal targets irradiated with high-intensity beams of gas ions. The investigations concerned ion implantation modes with the ion beam current density from several tens of mA/cm2 up to A/cm2 were presented. The ion beam power was varied due to the change of ion energy in the range from 0.6 to several keV and the pulse duty factor in the range of 0.2–0.8. The integral temperature of the target was measured with an electrically isolated thermocouple. To measure the dynamic change in the local temperature on the irradiated surface of target a high-temperature pulsed pyrometer KLEIBER 740-LO was used. Analysis of the experimental data obtained with the use of electrically isolated thermocouple, pulsed pyrometer, and numerical simulation revealed the presence of significant gradient temperature fields both over the surface and along the depth of targets irradiated by high-intensity ion beams.

Progress in low energy high intensity ion implantation method development

New results on the equipment development and advancement of the method of high-intensity ion implantation of metal, gases and low-energy semiconductors providing a long range effect of dopants penetration are presented in the article. The results of the research and development of plasma-immersion systems for the formation of ion beams with a current density of tens and hundreds of mA/cm2, a beam current exceeding 1 A at kilovolt accelerating voltages using ion extraction and beam focusing systems as part of a sphere or cylinder are shown. A comparative analysis of various systems, their advantages and disadvantages depending on the purpose are presented.The concept of low energy high intensity ion implantation (LEHI3) method is described. The features of the method as applied to the problems of deep modification of the microstructure and operational characteristics of metals and alloys are analyzed. The report presents the results of experimental studies of LEHI3 of aluminum, titanium, nitrogen into various structural materials. The possibility of ion doping of materials at depths of several tens and hundreds of micrometers is shown. Data are presented on the changes in the elemental composition, microstructure and properties of various materials depending on the ion current density of 10–500 mA/cm2, ion energy, implantation temperature and irradiation fluence of 1018–1022 ion/cm2.Based on the analysis of the obtained experimental data, the directions of further research are discussed in the framework of the development of the physical and technological foundations of the LEHI3 method of material properties modification at depths that are orders of magnitude greater than the projective ranges of ions.

Modification of the microstructure and properties of martensitic steel during ultra-high dose high-intensity implantation of nitrogen ions

In this work, we report a study of the chemical and phase composition, structural modifications and mechanical properties of martensitic stainless steel surface layers modified by high-intensity nitrogen ion implantation using a high current beam of low-energy nitrogen ions. The effect of ultrahigh-dose implantation of nitrogen ions into steel using a high-intensity repetitively pulsed beam of nitrogen ions with a current of 0.6 A (at an ion energy of 1.2 keV) and a sample temperature of 500 °C is investigated. The fluence of ion irradiation in the range from 6 × 1021 ions/cm2 to 2.25 × 1021 ions/cm2 varied by changing the current density and implantation time. The studies performed using transmission electron microscopy and X-Ray diffraction analysis of the microstructure and phase composition of the implanted samples showed that the surface-doped layer formed up to 75 μm thick and contains ferrite, iron nitride Fe4N, and chromium nitride CrN (α-phase – 70.88 vol.%, γ'-Fe4N – 16.30 vol.%, CrN – 12.82 vol.%). The obtained values of the coherent scattering region size of the formed chromium nitride and iron nitride indicate a very high dispersion of the elements in the ion-doped layer substructure. The data on changes in the surface morphology and microhardness of the near-surface layers are presented.

Improving the performance properties of titanium alloy VT6 after ion implantation with copper and aluminum ions

The objective of this work was to study the processes occurring on the surface of VT6 titanium alloy samples when implanting with copper and aluminum ions. Elemental composition, structural-phase state, mechanical and tribological properties of VT6 titanium alloy surface layers modified by aluminum and copper ions was being researched. As can be seen from the undertaken studies, the mode of high-intensity ion-implantation process makes it possible to obtain ion doped surface layers of VT6 alloy containing finely dispersed intermetallic phases and a solid solution of aluminum and copper in titanium of a composition varying in depth. The thickness of the ion-doped layer, the average grain size of the intermetallic phases and their conglomerates increases with the increase in implantation dose while aluminum implantation is in progress. It has been shown that the implantation of aluminum and copper ions into VT6 alloy leads to a considerable increase in its microhardness and wearability. Based on the research results, a conclusion on the positive effect of a structural-phase state of ion-doped titanium layers on their mechanical and tribological properties of VT6 titanium alloy has been drawn.

VT6 TITANIUM ALLOY WEARABILITY INCREASE VIA IMPLANTATION OF COPPER AND ALUMINUM IONS

The relevance of the article is due to the fact that the use of titanium alloys within friction joints is restrained by their low resistance to wear while traditional methods of increasing their wear resistance are ineffective. The objective of this work was to study the processes occurring on the surface of VT6 titanium alloy samples when implanting with copper and aluminum ions, as well as in friction. Elemental composition, structural-phase state, mechanical and tribological properties of VT6 titanium alloy surface layers modified by aluminum and copper ions during the high-intensity ion-implantation process was being researched. As can be seen from the undertaken studies, the mode of the high-intensity ion-implantation process makes it possible to obtain ion doped surface layers of VT6 alloy containing TiAl, Ti3Al, Ti3Cu, Ti2Cu, TiCu finely dispersed intermetallic phases and a solid solution of aluminum and copper in titanium of composition varying in depth. The thickness of the ion-doped layer, the average grain size of the intermetallic phases (from 18 to 55nm) and their conglomerates (from 45 to 280 nm) increases with the increase in implantation dose from 2⋅1017 to 1.2⋅1019 ion/cm2 while aluminum implantation (from 0.42 to 2.1 μm) is in progress. It has been shown that the implantation of aluminum and copper ions into VT6 alloy leads to a considerable increase in its microhardness and wearability. Based on the research results, a conclusion on the positive effect of a structural-phase state of ion-doped titanium layers on their mechanical and tribological properties of VT6 titanium alloy has been drawn.

Surface modification of Al by high-intensity low-energy Ti-ion implantation: Microstructure, mechanical and tribological properties

A high-intensity metal ribbon ion beam was generated using plasma immersion extraction and the acceleration of the metal ions with their subsequent ballistic focusing using a cylindrical grid electrode under a repetitively pulsed bias. To generate the dense metal plasma flow, two water-cooled vacuum arc evaporators with Ti cathodes were used. The ion current density reached 43 mA/cm2 at the arc discharge current of 130 A. High-intensity ion implantation (HIII) with a low ion energy ribbon beam was used for the surface modification of the aluminium. The irradiation fluence was changed from 1.5 × 1020 ion/cm2 to 4 × 1020 ion/cm2 with a corresponding increase in the implantation temperature from 623 to 823 K. The structure and composition of the Ti-implanted aluminium were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The mechanical properties and wear resistance were measured using nanoindentation and “pin-on-disk” testing, respectively. It was shown that the HIII method can be used to form a deep intermetallic Al3Ti layer. It has been established that a thin (0.4 μm) modified layer with a hcp Ti(Al) structure is only formed on the surface at 623 K, while the formation of the ordered Al3Ti intermetallic phase occurs at the implantation temperatures of 723 and 823 K. Despite the significant ion sputtering of the surface, the thickness of the modified layer increases from ~1 μm to ~6 μm, and the implantation temperature rises from 723 to 823 K. It was found that the homogeneous intermetallic Al3Ti layer with a thickness of up to 5 μm was formed at 823 К. The mechanical and tribological properties of the aluminium were substantially improved after HIII. For the Ti-implanted aluminium, the hardness of the surface layer increases from 0.4 GPa (undoped Al) to 3.5–4 GPa, while the wear resistance increases by more than an order of magnitude.

Modification of 40X13 steel at high-intensity nitrogen ion implantation

This paper presents the results of the formation of deep modified layers in 40X13 steel using a high-intensity repetitively pulsed nitrogen ion beam with a current density up to 0.25 A/cm2. An arc generator with a hot cathode provided the DC nitrogen plasma flow. A plasma immersion approach was used for high-frequency, short-pulse very intense nitrogen ion beam formation. A grid hemisphere with radii of 7.5 cm was immersed in the plasma. Negative bias pulses with an amplitude of 1.2 kV, a pulse duration of 4 μs, and a pulse repetition rate of 105 pulses per second were applied to the grid. The substrates were implanted at the temperature of 500 °C and various processing times ranging from 20 to 120 minutes with 1.2 keV nitrogen ions using a very-high current density up to 0.25 A/cm2 ion beams. The work explores the surface morphology, elemental composition, and mechanical properties of deep-layer modified 40X13 steel after low ion energy, very-high-intensity nitrogen ion beam implantation.