Ion-assisted Magnetron Sputtering Research Articles

Thermal, electrical, and mechanical properties of hard nitrogen-alloyed Cr thin films deposited by magnetron sputtering

CrN based materials, including stoichiometric CrN and Cr:N with a wide range of nitrogen contents, are commonly used as hard and corrosion-resistant coatings. Cr-rich films in this materials system can retain the bcc structure of metallic Cr with few percent of dissolved nitrogen, which can be used for tailoring the mechanical, thermal, and electrical properties. Here, we investigated low nitrogen containing Cr thin films deposited by high ion assisted magnetron sputtering with a substrate temperature of 200 °C. With the gas flow ratio maintained at fN2/Ar = 0.02, the substrate bias and the target power allows for control of the film composition (0.03 < N/Cr < 0.34). The films comprise a mixture of bcc-Cr and hexagonal Cr2N1-δ phases. The mechanical properties studied by nanoindentation and Brillouin inelastic light scattering revealed a hardening effect due to the multiphase nanostructure. The mechanical properties of the Cr:N films depend on the residual stress, on the amount of h- Cr2N1-δ phase and on the nanostructuring nature of the coatings. A maximum hardness of 37 GPa was achieved for a dense film with a Young's modulus of 340 GPa, a shear modulus of 118 GPa, and a relatively low thermal conductivity of 7 W/mK.

Fretting fatigue behaviors and surface integrity of Ag-TiN soft solid lubricating films on titanium alloy

Abstract Titanium alloys are widely used in industrial fields because of their superior characteristics, but they also have disadvantages leading to fretting fatigue (FF) damage. The silver-based composite films were deposited on a Ti6Al4V alloy substrate using ion-assisted magnetron sputtering for improving the fretting fatigue (FF) resistance of a Ti6Al4V alloy. The surface morphology was characterized by atomic force microscopy (AFM), and micro-structure was characterized by X-ray photoelectron spectroscopy measurements (XPS), X-ray diffractometry (XRD), and transmission electron microscopy (TEM), respectively. The bonding strength and toughness of films were analyzed using a repeated press–press test system that was manufactured in-house. The FF resistance of titanium alloy with the silver-based composite films was investigated using home-made FF devices. The results showed that the FF resistance of the titanium alloy was improved by the Ag-TiN composite films, which were fabricated with an Ag solid lubricating film doped with a hard TiN phase (60–80 at.% Ag). This is attributed to the fact that the composite films had better comprehensive strength-toughness behavior, friction lubrication property, and high bonding strength. However, when the atomic fraction of Ag in the composite film was larger than 90%, it became difficult to form the TiN phase, and it failed to improve the comprehensive strength-toughness behavior of the composite film.

The Effect of Modulation Ratio of Cu/Ni Multilayer Films on the Fretting Damage Behaviour of Ti-811 Titanium Alloy.

To improve the fretting damage (fretting wear and fretting fatigue) resistance of Ti-811 titanium alloy, three Cu/Ni multilayer films with the same modulation period thickness (200 nm) and different modulation ratios (3:1, 1:1, 1:3) were deposited on the surface of the alloy via ion-assisted magnetron sputtering deposition (IAD). The bonding strength, micro-hardness, and toughness of the films were evaluated, and the effect of the modulation ratio on the room-temperature fretting wear (FW) and fretting fatigue (FF) resistance of the alloy was determined. The results indicated that the IAD technique can be successfully used to prepare Cu/Ni multilayer films, with high bonding strength, low-friction, and good toughness, which yield improved room-temperature FF and FW resistance of the alloy. For the same modulation period (200 nm), the micro-hardness, friction, and FW resistance of the coated alloy increased, decreased, and improved, respectively, with increasing modulation ratio of the Ni-to-Cu layer thickness. However, the FF resistance of the coated alloy increased non-monotonically with the increasing modulation ratio. Among the three Cu/Ni multilayer films, those with a modulation ratio of 1:1 can confer the highest FF resistance to the Ti-811 alloy, owing mainly to their unique combination of good toughness, high strength, and low-friction.

Characterization and mechanical properties investigation of TiN-Ag films onto Ti-6Al-4V

To investigate their effect on fretting fatigue (FF) resistance of a Ti-6Al-4V alloy, hard solid lubricating composite films of TiN with varying silver contents (TiN-Ag) were deposited on a Ti-6Al-4V alloy using ion-assisted magnetron sputtering. The surface morphology and structure were analyzed by atomic force microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, and transmission electron microscopy. The hardness, bonding strength, and toughness of films were tested using a micro-hardness tester, scratch tester, and a repeated press–press test system that was manufactured in-house, respectively. The FF resistance of TiN-Ag composite films was studied using self-developed devices. The results show that the FF resistance of a titanium alloy can be improved by TiN-Ag composite films, which were fabricated using hard TiN coating doped with soft Ag. The FF life of Ag0.5, Ag2, Ag5, Ag10 and Ag20 composite films is 2.41, 3.18, 3.20, 2.94 and 2.87 times as great as that of the titanium alloy, respectively. This is because the composite films have the better toughness, friction lubrication, and high bonding strength. When the atomic fraction of Ag changes from 2% to 5%, the FF resistance of the composite films shows the best performance. This is attributed to the surface integrity of the composite film is sufficiently fine to prevent the initiation and early propagation of FF cracks.

Thick beryllium coatings by ion-assisted magnetron sputtering

Abstract

The structure and properties of VN-VCN-VC coatings deposited by a high energy ion assisted magnetron sputtering method

In the last years the scientific interest for transition metal compounds, used for protective and functional coatings, was extended and included, besides Ti, other elements such as Zr, V, and Hf as potential candidates. Due to their promising mechanical properties, and resistance to high temperature, V compounds received an increasing attention from scientists and end-users.The present work is dedicated to the study of the characteristics and the properties of the vanadium based multilayer hard coatings deposited by a magnetron sputtering process, assisted by a high voltage pulse discharge. Different multilayer coatings (VC/VN, VN/VC, VN/VCN/VC) were obtained and comparatively analyzed relative to vanadium nitride and vanadium carbide monolayers. Coatings with microhardness up to 3700HV 0.05 and thickness up to 20μm have been produced.Elemental and phase composition, as well as tribological characteristics (wear factor and friction coefficient) of the coatings were investigated. The chemical and structural investigations were performed by GDOES (Glow Discharge Optical Emission Spectrometry), EDX (Energy Dispersive X-ray analysis), XRD (X-ray Diffraction) and SEM (Scanning Electron Microscopy), while microhardness measurements and wear test were used to assess the coatings characteristics. The friction coefficient and the wear resistance of the coatings were evaluated by using pin on disc tests in unlubricated conditions.

Improvement of the fretting damage resistance of Ti-811 alloy by Cu/Ni multilayer films

The Cu/Ni multilayer films were prepared on the titanium alloy surface by ion-assisted magnetron sputtering deposition (IAD) technique. The Cu/Ni multilayer films could significantly improve the resistance of fretting wear and fretting fatigue (FF) of Ti-811 alloy at room temperature. The FF resistance of the titanium alloy substrate did not increase monotonically with increase in the modulation period thickness of the Cu/Ni multilayer films. The Cu/Ni multilayer films with modulation period thickness of 200 nm had the highest FF resistance among the prepared Cu/Ni multilayer films for its comprehensive properties with high toughness, high strength and good lubricating action.

Investigation of the physical properties of ion assisted ZrN thin films deposited by RF magnetron sputtering

Ion bombardment during thin film growth is known to cause structural and morphological changes in the deposited films, thus affecting their physical properties. In this work zirconium nitride films have been deposited by the ion assisted magnetron sputtering technique. The ion energy is controlled by varying the voltage applied to the substrate in the range 0–25 V. The deposited ZrN films are characterized for their structure, surface roughness, oxygen contamination, optical reflectance and electrical resistivity. With increasing substrate voltage crystallinity of the films is enhanced with a preferential orientation of the ZrN grains having the (1 1 1) axis perpendicular to the substrate surface. At the same time, a decrease in electrical resistivity and oxygen contamination content is observed up to 20 V. A higher substrate voltage (25 V) causes an inversion in the observed experimental trends. The role of oxygen contamination decrease and generation of nitrogen vacancies due to ionic assistance have been considered as a possible explanation for the experimental results.

Synthesis and Characterization of (C, N)-Alloyed Stainless Steel Coatings by High Energy Ion Assisted Magnetron Sputtering Deposition

In this article, (C, N) alloyed austenitic stainless steel coatings (SSC) (or hybrid S-phase with both carbon and nitrogen) were produced by a magnetron sputtering deposition process combined with ion implantation (CMSII). This technique involves a periodical high energy ion bombardment of the coating during its growth, which has a beneficial effect on the structure and properties of the deposited coating. The influence of the nitrogen and carbon addition to the deposition atmosphere on the structure, chemical composition, and coating morphology was investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and glow discharge optical spectrometry (GDOS) techniques. Wear tests were carried out and the results were compared with low temperature plasma nitrided austenitic stainless steel. Corrosion behavior in Ringer's solution was also evaluated.

Synthesis and Characterization of (C, N)-Alloyed Stainless Steel Coatings by High Energy Ion Assisted Magnetron Sputtering Deposition

In this paper, (C,N) alloyed austenitic stainless steel coatings (or hybrid S-phase with both carbon and nitrogen) were produced by a magnetron sputtering deposition process combined with ion implantation (CMSII). This technique involves a periodical high energy ion bombardment of the coating during its growth, which has a beneficial effect on the structure and properties of the deposited coating. The influence of the nitrogen and carbon addition to the deposition atmosphere on the structure, chemical composition and coating morphology was investigated using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Glow Discharge Optical Spectrometry (GDOS) techniques. Wear tests were carried out and the results were compared with low temperature plasma nitrided austenitic stainless steel.

Tantalum thin films deposited by ion assisted magnetron sputtering

This work investigated the effect of ion bombardment on tantalum thin films deposited by radio frequency magnetron sputtering at ambient temperature on (100) oriented silicon and polycrystalline aluminum. Negative bias voltage, 0 to − 300 V, was applied to the substrate to control the energy of the ions bombarding the growing film. The films were characterized by X-ray diffraction, Rutherford backscattering, scanning electron microscopy, and atomic force microscopy. The desired pure body centered cubic phase Ta films were deposited with − 150 V substrate bias and with comparable atom and ion fluxes, conditions significantly different than reported earlier, and achievable in a relatively simple system that is easy to scale to industrial operation.

Semiconducting cubic boron nitride

Abstract We present new developments in the preparation of semiconducting cubic boron nitride. The thin films were grown on (100) silicon substrates using electron cyclotron resonance (ECR) ion-assisted magnetron sputtering with the kinetic energy of the incident nitrogen ions controlled by a dc substrate bias. Using this technique we have been able to grow thick (up to 2 μm) boron nitride films containing 100% of the cubic phase. We have found that the relatively high nitrogen ion energy (∼ 100 cV), required to nucleate the cubic phase, can be reduced substantially (to ∼ 60 eV) once the cubic phase is formed, leading to reduced film stress, larger grain size (∼ 1000 A) and improved adhesion. The films have p -type conductivity. The carrier activation energy is 60 meV and we have observed Hall mobilities of 500 cm 2 V −1 s −1 at n a ≈ (5 × 10 18 cm −3 ).

Use of adsorption calorimetry in studying the oxidation of hydrogen on silver

To investigate their effect on fretting fatigue (FF) resistance of a Ti-6Al-4V alloy, hard solid lubricating composite films of TiN with varying silver contents (TiN-Ag) were deposited on a Ti-6Al-4V alloy using ion-assisted magnetron sputtering. The surface morphology and structure were analyzed by atomic force microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, and transmission electron microscopy. The hardness, bonding strength, and toughness of films were tested using a micro-hardness tester, scratch tester, and a repeated press–press test system that was manufactured in-house, respectively. The FF resistance of TiN-Ag composite films was studied using self-developed devices. The results show that the FF resistance of a titanium alloy can be improved by TiN-Ag composite films, which were fabricated using hard TiN coating doped with soft Ag. The FF life of Ag0.5, Ag2, Ag5, Ag10 and Ag20 composite films is 2.41, 3.18, 3.20, 2.94 and 2.87 times as great as that of the titanium alloy, respectively. This is because the composite films have the better toughness, friction lubrication, and high bonding strength. When the atomic fraction of Ag changes from 2% to 5%, the FF resistance of the composite films shows the best performance. This is attributed to the surface integrity of the composite film is sufficiently fine to prevent the initiation and early propagation of FF cracks.