Closed Field Unbalanced Magnetron Sputter Ion Plating Research Articles

Comparative Performance Evaluation of Magnetron Sputtered TiN, AlCrN, and TiAlCrN Coatings

This study presents a comparative performance evaluation of magnetron-sputtered TiN, AlCrN, and TiAlCrN coatings on tool steel substrates. Coatings play a pivotal role in enhancing the durability of engineering components exposed to harsh conditions. TiN is known for outstanding hardness and durability, AlCrN for superior wear resistance, and TiAlCrN for exceptional thermal stability and oxidation resistance. The substrate (EN 1.2363) underwent PVD coating using a closed-field unbalanced magnetron sputter ion plating (CFUBMSIP) process in a water-cooled stainless-steel vacuum chamber with four magnetron ports, operating for 3 hours per batch followed by 12 hours of natural convection cooling, utilizing TiN, AlCrN, and TiAlCrN films deposited for 180 minutes in an Ar and nitrogen atmosphere. X-ray diffraction (XRD) revealed distinctive crystal structures, with all coatings exhibiting a common preferred orientation of the (111) plane and TiAlCrN showing a ternary nitride phase. Scanning electron microscopy (SEM) images displayed the compact nature of TiAlCrN with finer grains, while TiN exhibited a densely compacted with no evidence of delamination and AlCrN showed denseness with smaller grains. Nano-indentation test was conducted to assess the coatings' hardness and elastic modulus. TiAlCrN exhibited the highest hardness (3091±243 HV), highest elastic modulus (369.86±54.19 GPa), and the best wear rate (0.1887 x 10-4 mm3/Nm-1) suggesting potential suitability for applications demanding superior rigidity and wear resistance. The study provides valuable insights for materials scientists and engineers in optimizing coating selection for specific applications.

A comprehensive performance study of NiCrCN coated 316L stainless steel as bipolar plates for proton exchange membrane fuel cell

NiCrCN coatings are deposited on the surfaces of 316 L stainless steel (SS316L) substrates via closed field unbalanced magnetron sputtering ion plating (CFUMSIP) to improve the corrosion resistance and electrical conductivity of proton exchange membrane fuel cell (PEMFC) bipolar plates. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results show that CrN, Cr2N, Ni, and Cr7C3 phases exist in NiCrCN coatings. As the Cr target current grows from 2 A to 6 A, the Cr7C3 content in the carbon compounds increases from 3.39% to 11.46%, and the interfacial contact resistance (ICR) value is reduced from 18.0 mΩ cm2 to 11.2 mΩ cm2. When the Cr target current reaches 4 A, the NiCrCN coating shows the most intensive cross-sectional growth pattern by cold-field scanning electron microscopy (CFSEM) results, and the current density after prolonged polarization (0.11 μA cm−2) is much lower than that of SS316L (1.86 μA cm−2).

Investigation of corrosion protection with conductive chromium-aluminum carbonitride coating on metallic bipolar plates

To further enhance the performance of metal bipolar plates, the CrAlCN coating with high corrosion resistance and conductivity was deposited on the SS316L substrate by using Closed Field Unbalanced Magnetron Sputter Ion Plating (CFUMSIP) technique. Meanwhile, the inexpensive acetylene gas (C2H2) was utilized as a carbon source. XRD and XPS results indicate that the proportion of carbides in the coating increase with increasing carbon contents. Electrochemical measurements show that the C-doped coating significantly improves the corrosion resistance of the SS316L bipolar plates. The C doping enhances the conductivity of the CrAlN coating, and the C-doped sample obtains the lowest ICR value (2.94 mΩ cm2, before corrosion), which is well below the DOE target (≤10 mΩ cm2). The excellent conductivity and hydrophobicity of C-doped coating increase the power density of a single cell. This study demonstrates that the CrAlCN coatings have great application prospects in the bipolar plates field.

Investigation of corrosion properties with Ni–P/TiNO coating on aluminum alloy bipolar plates in proton exchange membrane fuel cell

Aluminum alloy bipolar plates have unique application potential in proton exchange membrane fuel cell (PEMFC) due to the characteristics of lightweight and low cost. However, extreme susceptibility to corrosion in PEMFC operation condition limits the application. To promote the corrosion resistance of aluminum alloy bipolar plates, a Ni–P/TiNO coating was prepared by electroless plating and closed field unbalanced magnetron sputter ion plating (CFUMSIP) technology on the 6061 Al substrate. The research results show that Ni–P interlayer improves the deposition effect of TiNO outer layer and increase the content of TiN and TiOxNy phases. Compared to Ni–P and TiNO single-layer coatings, the Ni–P/TiNO coating samples exhibited the lowest current density value of (1.10 ± 0.02) × 10−6 A·cm−2 in simulated PEMFC cathode environment. Additionally, potential cyclic polarization measurements were carried out aiming to evaluate the durability of the aluminum alloy bipolar plate during the PEMFC start-up/shut-up process. The results illustrate that the Ni–P/TiNO coating samples exhibit excellent stability and corrosion resistance.

Study on Corrosion Resistance and Conductivity of TiMoN Coatings with Different Mo Contents under Simulated PEMFC Cathode Environment.

TiMoN coatings with different Mo contents on a SS316L substrate are deposited by using closed field unbalanced magnetron sputtering ion plating (CFUMSIP) technology to enhance the corrosion resistance and durability of stainless steel (SS) bipolar plates (BPs) in proton exchange membrane fuel cell (PEMFC) during the start-up/shut-down process. The electrochemical test results illustrate that TiMoN-4A coating has extremely good corrosion resistance compared to other coatings. The potentiostat polarization (+0.6 VSCE) tests indicate that the corrosion current density (Icorr) of TiMoN-4A coating is 5.22 × 10−7A cm−2, which meets the department of energy 2020 targets (DOE, ≤1 × 10−6 A cm−2). Otherwise, TiMoN-4A coating also exhibits the best corrosion resistance and stability in potentiostatic polarization, electrochemical impedance spectroscopy (EIS), and high potential (+1.2VSCE) polarization tests. The interfacial contact resistance (ICR) measurement results show that TiMoN-4A coating has the minimum ICR of 9.19 mΩ·cm2, which meets the DOE 2020 targets (≤10 mΩ·cm2).

Сравнительная оценка триботехнических характеристик твердосмазочных покрытий, нанесенных методом замкнутого поля несбалансированного магнетронно-ионного распыления, для различных условий функционирования

This paper presents a comparative assessment of the tribotechnical characteristics of friction pairs with solid lubricant coatings (SLC) based on the MoS2 suspension application of VNII NP 212 and SLCCFUBMSIP deposited by the closed field unbalanced magnetron sputter ion plating (CFUBMSIP) of combined compositions MoS2+Ti, MoS2+Zr, MoS2+Cr , MoS2+W. It was established that under normal atmospheric conditions in the friction modes corresponding to the contact friction temperature of 157 °С, the life of SLCCFUBMSIP was 42.1% higher, and the coefficient of friction (ffr) was on average 2 times lower than that of SLC VNII NP 212. The average value of the life reduction coefficient for SLCCFUBMSIP during the transition from normal atmospheric conditions to water was 2.98. Under normal atmospheric conditions and in water, the SLCCFUBMSIP coefficient of friction was in the range of 0.02–0.04, and in an oil environment it ranged from 0.03 to 0.08. SLCCFUBMSIP based on pure MoS2 in normal atmospheric conditions, in water and oil was practically unusable.

Enhancing the adhesion strength and wear resistance of nanostructured NiCrN coatings

NiCrN coatings, with varying Ni contents, were deposited on AISI M2 tool steel substrates using closed field unbalanced magnetron sputtering ion plating (CFUMSIP) where the NiCr target current (INiCr) was varied. An evolution of the graded columnar structures was found in these coatings, where increased incorporation of nickel induced grain refinement, as well as a reduction in values of both hardness (H), elastic modulus (Er) and elastic recovery (We). The influence of variations in the microstructure and mechanical properties on the adhesion behaviour and tribological performance of these NiCrN coatings was investigated. Scratch test results demonstrated that higher critical loads (Lc1 and Lc2) suppressed both cohesive and adhesive failure in coatings which exhibited higher values of H/Er, H3/Er2 and We. The failure mode under progressive scratch loading was controlled by the hierarchical design of the NiCrN coatings that enhanced adhesion and prevented crack propagation through the coating. For the coatings with lower Ni contents improved wear resistance was ascribed to not only higher H/Er, H3/Er2 and We values of these coatings, but also the graded interlayers that delocalised the stress distribution during dry sliding.

Harmonizing mechanical responses of nanostructured CrN coatings via Ni additions

CrN coatings are often brittle and prone to abrupt failure. Incorporation of Ni is known to have significant effects on the chemical composition, microstructure and mechanical behaviour of chromium nitride coatings synthesised by PVD, and thus imparting toughness. In this study, a series of NiCrN coatings, with varying Ni concentrations, were deposited onto AISI M2 tool steel substrates through closed-field unbalanced magnetron sputtering ion plating (CFUMSIP). The phase compositions, microstructure, mechanical properties and deformation behaviour of the coatings were characterised by XRD, AFM, FIB, TEM/EDS and indentation testing. Residual stresses of these as-prepared coatings were measured by the XRD-sin2ψ method. A columnar structure was observed in all coatings, although grain refinement at higher NiCr target currents was noted. High hardness values of ~20 GPa were found in the coatings with the lower Ni (~5–14 at%) contents, associated with the effects of solid solution hardening, high compressive residual stress and grain refinement. Moreover, significant damage-tolerance, coupled with good hardness values (greater than ~12 GPa), was found in the NiCrN coatings deposited at INiCr ≥ 2 A. The presence of a metallic nickel-rich phase, together with nanoscale porosity, may contribute to stress dissipation and help maintain structural integrity.

Durability and degradation of CrMoN coated SS316L in simulated PEMFCs environment: High potential polarization and electrochemical impedance spectroscopy (EIS)

The high potential on the cathode side originated from the start-up/shut-down processes is the one that cannot be ignored, which will accelerate degradation of the bipolar plates and increase the interfacial contact resistance (ICR) eventually degrade the performance of PEMFCs. Therefore, the coating with corrosion resistance and conductivity is in urgent need of development. CrMoN coating is deposited on SS316L by closed field unbalanced magnetron sputter ion plating (CFUMSIP) with an aim to improve corrosion resistance and conductivity of SS316L under PEMFCs at shut-up/shut-down stages. In terms of high potential polarization test, the corrosion current density and ICR values are found to increase as the applied potential increases. The electrochemical degradation of CrMoN coated SS316L is investigated by electrochemical impedance spectroscopy (EIS). After 40 days of immersion, the charge transfer resistance (Rct) of the CrMoN-4A coated SS316L is approximately 14 times greater than that of the uncoated SS316L and the ICR values are 11.2 mΩ cm2, indicating that the CrMoN-4A coating still has high corrosion resistance and well conductivity after long time immersion.

Niobium doped amorphous carbon film on metallic bipolar plates for PEMFCs: First principle calculation, microstructure and performance

Metallic bipolar plates (BPPs) are a promising candidate to replace conventional graphite BPPs due to higher power density and lower cost in proton exchange membrane fuel cells (PEMFCs). Surface coating is essential to enhance interfacial conductivity and corrosion resistance. Amorphous carbon (a-C) films have attracted broad attention from both academia and industry. This study incorporated Niobium (Nb) into a-C to further enhance its performance. First principle calculation was introduced to investigate the evolution mechanism of bond and phase by Nb doping and instruct the coating design. Then, a series of Nb-doped a-C samples were deposited by closed field unbalanced magnetron sputtering ion plating (CFUBMSIP) method. The microstructure was systematically characterized by SEM, XRD, Raman spectrum, and XPS. Interfacial contact resistance (ICR) and electrochemical corrosion were also tested to evaluate the effect of Nb doping. A higher C-sp2/C-sp3 ratio was observed in a-C film with moderate Nb doping. As a result, the ICR decreased to 1.22 mΩ•cm2 from initial value of 4.41 mΩ•cm2. Besides, the doped Nb also refined grain size and increased the film compactness, which was beneficial for corrosion resistance. Rct, which reflects the relative anti-corrosive property, was increased from 1.8 × 106 Ω•cm2 to 3.29 × 106 Ω•cm2. Moreover, the current density in 0.84 V (vs. SHE) potentiodynamic polarization is 3.59 × 10−7 A/cm2, lower than 4.59 × 10−7 A/cm2 of a-C films. Besides, the current density in 0.84 V (vs. SHE) potentiostatic polarization shows the same tendency. The enhanced performance of Nb-doped a-C coatings would advance the commercialization of metallic BPPs for PEMFCs.

The influence of plasma nitriding on microstructure and properties of CrN and CrNiN coatings on Ti6Al4V by magnetron sputtering

In this paper, the CrN and CrNiN coatings were deposited on the non-nitrided and nitrided Ti6Al4V alloys with the method of closed-field unbalanced magnetron sputter ion plating (CFUBMSIP). The influence of plasma nitriding treatment on microstructure, mechanical and tribological properties of Physical Vapor Deposition (PVD) films was evacuated by means of SEM (EDS), XRD, Rockwell-C indentation testing, nanoindentation testing, and ball-on disc tribotesting. With the addition of Ni, the preferred orientation changes to CrN (200) and the grain is refined. The indentation tests indicated that the duplex treated samples exhibited the best combined properties. The nanoindentation testing results showed that the hardness of the coatings increased, the plastic deformation reduced and they had higher H3/E2 values than PVD coatings with the plasma nitriding before PVD treatment due to the increase of substrate's load bear capacity after plasma nitriding process. The friction and wear tests demonstrated that the tribological performance of the PVD coatings improved after plasma nitriding which is attributed to the enhanced the mechanical compatibility between the hard PVD coating and soft substrate and the resistance of CrN coating is better than that of CrNiN coating because of the transfer layer (constituted of TiN and Ti2N) deposited by nitriding.

EFFECTS OF Mo CONTENT ON THE MICRO-STRUCTURE AND TRIBOLOGICAL PROPERTIES OF CrMoAlN FILMS

In recent decades, CrAlN coatings have been widely used for cutting tools due to their high hardness, good wear resistance, especially excellent thermal stability and oxidation resistance. However, the rapid development in high speeds and dry cutting applications demands further improvement in hardness and wear properties of CrAlN coatings. Mo nitrides coatings are commonly used as protective surface layers against wear and corrosion. The combination of CrAlN and Mo may lead to the development of new composite coatings with superior wear properties. In this study, the CrMoAlN multilayer coatings with different Mo contents were deposited on M2 tool steel and silicon wafers substrates by closedfield unbalanced magnetron sputtering ion plating (CFUMSIP) technique in a gas mixture of Ar+N2. The chemical composition, surface and cross sectional morphologies, microstructure, mechanical and tribological properties of coatings were studied by EDS, SEM, XRD, XPS, nano-indentation and pin-on-disk tribometer, respectively. The results indicate that the CrMoAlN coatings exhibit fcc structure. Mo atoms substitute Cr and/or Al atoms in CrAlN lattice forming the solid solution CrMoAlN coatings. The surface and cross-sectional morphologies of the CrMoAlN coatings show that the grain size and the column width decrease with the increasing of Mo content. Nano-indentation result reveals a promoted hardness and elastic modulus *浙江省自然科学基金资助项目Y15E050060 收到初稿日期: 2015-09-21,收到修改稿日期: 2016-03-09 作者简介:楼白杨,女, 1958年生,教授,博士 DOI: 10.11900/0412.1961.2015.00493 第727-733页 pp.727-733

Influence of Cr-C film composition on electrical and corrosion properties of 316L stainless steel as bipolar plates for PEMFCs

Stainless steel (SS) has received much attention in recent years as an alternative material for bipolar plates (BPPs) in proton exchange membrane fuel cells (PEMFCs). However, stainless steel BPPs are still required to combat corrosion in the acid environment without forming oxidants, passive layers and metal ions. In this study, multilayered chromium-carbon (Cr-C) film is deposited on SS316L sheet as BPPs using closed field unbalanced magnetron sputter ion plating (CFUBMSIP). Five films with different composition are deposited and the influence of chromium content adjusted by sputtering current is characterized by X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Interfacial contact resistance (ICR) between coated SS316L sheets and gas diffusion layer (GDL) is measured. Potentiodynamic and potentiostatic tests are conducted to evaluate the corrosion resistance of the coated samples. Experimental results show that Cr-C film with content of Cr0.75C5 presents the optimal performance, i.e. the interfacial contact resistance(ICR) reduces to 1.4 mΩ cm2 under a compaction pressure of 1.4 MPa, and the corrosion current density reaches 1.046 μA cm−2 in the PEMFCs cathodic environment (0.5 M H2SO4 + 5 ppm HF solution at 70 °C, 0.6 V vs. SCE). The performance variation of five films can be preliminarily explained by the crystallographic structure and chemical composition analysis.

Multilayered TiAlN films on Ti6Al4V alloy for biomedical applications by closed field unbalanced magnetron sputter ion plating process

Ti6Al4V alloy has been widely used as a suitable material for surgical implants such as artificial hip joints. In this study, a series of multilayered gradient TiAlN coatings were deposited on Ti6Al4V substrate using closed field unbalanced magnetron sputter ion plating (CFUBMSIP) process. Taguchi design of experiment approach was used to reveal the influence of depositing parameters to the film composition and performance of TiAlN coatings. The phase structure and chemical composition of the TiAlN films were characterized by X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Mechanical properties, including hardness, Young's modulus, friction coefficient, wear rate and adhesion strength were systematically evaluated. Potentiodynamic tests were conducted to evaluate the corrosion resistance of the coated samples in Ringer's solution at 37°C to simulate human body environment. Comprehensive performance of TiAlN films was evaluated by assigning different weight according to the application environment. S8, deposited by Ti target current of 8A, Al target current of 6A, bias voltage of −60V and nitrogen content with OEM (optical emission monitor) value of 45%, was found to achieve best performance in orthogonal experiments. Depositing parameters of S8 might be practically applied for commercialization of surgical implants.

Amorphous Zr-based thin films fabricated by magnetron sputtering for potential application in hydrogen purification

Amorphous hydrogen separation membranes are under development because of their resistance to hydrogen embrittlement, improved mechanical properties, resistance to corrosion and most importantly lower intrinsic cost. The Closed Field Unbalanced Magnetron Sputter Ion Plating (CFUBMSIP) is a versatile technique for deposition of high quality thin-films of almost any composition, while enabling the control of film size, thickness and shape. In this work, it was demonstrated that thin-films (∼3–6μm) of amorphous Zr40.5Ni59.5, Zr54Cu46 and Zr30Cu57.5Y12.5 could be deposited onto glass substrates by the CFUBMSIP technique. XRD measurements only showed one broad peak for each alloy, with a peak centred between 36° and 42° 2θ, indicating that the films were amorphous. Surface analysis by SEM and confocal microscopy suggest deposition of continuous films. The thermal stability of the films appears to be mainly governed by the alloying elements and their compositions. However, the measured activation energies indicated that the nucleation and growth mechanism in the magnetron sputtered films may be different from that reported for melt-spun amorphous alloys with similar compositions.

The deposition of crystallized TiO2 coatings by closed field unbalanced magnetron sputter ion plating

Metallic oxide coatings, for example TiO2, are of increasing technological importance in a wide range of industrially relevant functional surfaces on components for renewable energy sector, self-cleaning, antimicrobial surfaces etc.Reactive closed field unbalanced magnetron sputter ion plating (CFUBMSIP) provides an effective, industrially-compatible processing route for the deposition of metallic oxides, with controlled composition, structure, mechanical, electronic and optical properties. The production of crystallized as-deposited TiO2 thin coatings by reactive CFUBMSIP process is described. The arrangement of the deposition system; deposition parameters, including: working gases, deposition pressure, the sputtering power; and the influence of interlayer on the nucleation and the crystalline structure of TiO2 coatings are investigated.

Research on Microstructure and Tribological Properties of Cr-Based Hard Coatings

In this paper, three kinds of Cr-based hard coatings have been studied for its structural, mechanical and tribological properties at room temperature. By the technology of closed field unbalanced magnetron sputter ion plating (CFUMSIP), CrN CrAlN and CrTiAlN hard coatings were deposited onto DC53 cold die steel and silicon (100) substrate. The coatings were characterized by means of field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), microhardness tester, optical microscope and ball-on-disc tribometer, in order to check their structural, as well as to determine the mechanical and tribological properties. The experimental results showed that the CrTiAlN coating performed better than the CrN coating and the CrAlN coating in terms of mechanical and tribological properties. The wear resistances of CrN, CrAlN and CrTiAlN coatings have been significantly improved compared with DC53 steel substrate.

Raman analysis of DLC and Si-DLC films deposited on nitrile rubber

In this study a hybrid diamond-like carbon (DLC) and silicon doped diamond-like carbon (Si-DLC), with and without Si–C interlayers, were deposited onto nitrile rubber substrates. The deposition was done in a closed field unbalanced magnetron sputtering ion plating (CFUBMSIP) rig in Ar/C4H10 plasma. A combination of visible (488nm) and ultra-violet (UV; 325nm) Raman analysis was used to determine the G-peak dispersion of the films. Raman analysis was also used to estimate the hydrogen concentration and residual stress in the films. Calculated hydrogen values for all of the films were between 26 and 31%. The residual stress estimates of the films indicated that the inclusion of Si dopant and Si–C interlayers reduced compressive stress in these films. Raman analysis of the wear tracks indicated an increase in the G-peak position which could indicate that graphitization occurred during pin-on-disc experiments.

Effect of CrTiAlN Coatings on High-Temperature Oxidation Behavior of H13 Steel

CrTiAlN hard coatings have been deposited on H13 steel for improving the oxidation resistance by Closed Field Unbalanced Magnetron Sputter Ion Plating (CFUMSIP). The phase components, surface and section morphology of H13 steel before and after oxidation were analyzed by XRD and SEM. The results showed that the columnar crystal film possesses three major parts, i.e., the internal Cr bonding layer, the intermediate CrN transition layer, the external CrTiAlN gradient coating. The selective oxidation of Cr element was found on the surface of uncoated H13 steel while oxidation, but a continuous protective layer was not formed because of low Cr content, finally a lot of alpha Fe2O3 particles took place on the surface of H13 steel owing to the oxidation of the matrix element. O element can diffuse much more easily through the coating and oxide scales at 800 °C, and spallation and cracks were not found during the oxidation. These results indicated that the CrTiAlN coating have excellent high-temperature oxidation resistance at 800 °C.

Composition optimization of multilayered chromium-nitride–carbon film on 316L stainless steel as bipolar plates for proton exchange membrane fuel cells

The composition of multilayered chromium-nitride-carbon (Cr-N-C) film has great influence on the performance of coated 316L stainless steel (SS316L) as bipolar plates for proton exchange membrane fuel cells (PEMFCs). In this study, five films with different composition are deposited by closed field unbalanced magnetron sputter ion plating (CFUBMSIP) and the influence of nitrogen content adjusted by a closed-loop optical emission monitor (OEM) is evaluated. The phase structure and chemical composition of the films are characterized by X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Interfacial contact resistance (ICR) between coated samples and gas diffusion layer (GDL) is measured. Potentiodynamic and potentiostatic tests are conducted to evaluate the corrosion resistance of coated samples. Experimental results show that Cr-N-C film with OEM setting of 60% presents the best performance, i.e. the ICR reduces to 2.11 mΩ cm2 under a compaction pressure of 1.4 MPa, and the corrosion current density reaches 0.308 μA cm−2 in the PEMFCs cathodic environment (0.5 M H2SO4 + 5 ppm HF solution at 70 °C, 0.6 V vs. SCE). Therefore, this study indicates that Cr-N-C film with OEM setting of 60% achieves optimal film composition and may be practically applied for commercialization of PEMFCs technology.