Field Unbalanced Magnetron Sputtering Research Articles

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).

Influence of substrate bias on the scratch, wear and indentation response of TiSiN nanocomposite coatings

TiSiN coatings were synthesised onto AISI M42 tool steel substrates via closed field unbalanced magnetron sputtering ion plating , using bias voltages of −40 and −50 V. The aim of this study is to investigate the underlying deformation mechanisms of TiSiN coatings, prepared at two different substrate bias voltages, following scratching, wear and indentation tests . A graded columnar microstructure evolved in these coatings. A hardness value of ~30.2 GPa was determined in the coating prepared at the lower bias voltage (i.e., −40 V), which was correlated to the fine nanocomposite structure and the presence of a high compressive residual stress. Of note, for the coating deposited at −40 V enhanced scratch adhesion strength , i.e., higher critical loads (L c1 and L c2 ) against cohesive and adhesive failure were determined with the higher H/E r and H 3 /E r 2 values. The improved scratch resistance was ascribed to the hierarchical structure that hindered crack propagation in the TiSiN coatings during progressive loading. An approximately 21% decrease in wear rate was obtained at the lower bias voltage, which was attributed to the slightly lower Si concentration (~8.3 at.%) and, in turn, higher hardness. Deformation behaviour under indentation loading was dominated by shear sliding along the columnar grain boundaries. • ~20% increase in L c1 was found in the TiSiN coating with the lower Si content. • The scratch resistance was enhanced by the coating's hierarchical structure. • ~21% reduction in wear rate was achieved in the coating with the lower Si content. • Indentation deformation was governed by columnar shear sliding.

Investigation of high potential corrosion protection with titanium carbonitride coating on 316L stainless steel bipolar plates

In order to improve the durability of stainless steel bipolar plates at high potential during the start-up/shut-down process of proton exchange membrane fuel cell (PEMFC), TiN and TiCN coatings with different C element contents are deposited on the 316L stainless steel substrates by using Closed Field Unbalanced Magnetron Sputter Ion Plating. The electrochemical test results show that the TiCN-2sccm sample possesses excellent corrosion resistance compared to other samples. The results of interfacial contact resistance (ICR) measurements show that the minimum ICR value of the TiCN-2sccm sample is 10 mΩ cm2, which meets the Department of Energy targets.

TiN versus TiSiN coatings in indentation, scratch and wear setting

The indentation response, scratch behaviour and wear performance of binary TiN and ternary TiSiN coatings under a variety of loading conditions were comparatively studied. The coatings were fabricated onto M42 steel substrates via closed field unbalanced magnetron sputtering ion plating. A maximum hardness value of ~40 GPa was obtained for one of the TiSiN coatings as compared to ~28 GPa for TiN. This was attributed to the nanocomposite structure, grain refinement, solid solution hardening and the higher compressive residual stress in the ternary coatings. The damage resistance of both the TiN and TiSiN coatings under indentation loading was governed by the dampening effects of sliding or shearing of the columnar grains along the grain boundaries coupled with the coatings’ respective mechanical characteristics. Improved scratch adhesion properties (i.e., higher LC1, LC2 and CPR values) were also observed for the TiSiN coatings that were underlain by their superior mechanical properties along with the graded structure, promoting the capacity to resist crack formation and delamination. Lower wear rates for the TiSiN coatings during dry sliding were found to be consistent with their higher H/Er, H3/Er2 and We values.

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.

Effect of Al content on the corrosion resistance and conductivity of metal nitride coating in the cathode environment of PEMFCs

In this paper, TiN coatings doped with various Al contents are settled on stainless steel 316L (SS316L) as bipolar plates of proton exchange membrane fuel cells (PEMFCs) through closed field unbalanced magnetron sputter ion planting. The influence of Al doping on the phase structure, surface morphology, corrosion resistance, passive film, interfacial contact resistance (ICR) and contact angle are studied. According to results of X-ray diffraction (XRD), the TiAlN coated samples have grain refinement. From the results of scanning electron microscope (SEM), TiAlN coatings are dense and uniform. Based on the potentiodynamic polarization test results, TiAlN-2A coating exhibits the highest corrosion potential of 0.17 VSCE and the lowest corrosion current density of 1.42×10−7 A cm−2 in the simulated PEMFCs cathode environment, which completely meets the DOE 2020 technical targets (<1×10−6 A cm−2), as well as the best stability and the lowest current density in the cathode potentiostatic polarization test. In addition, the electrochemical impedance spectroscopy (EIS) test reveals that TiAlN-2A coating has the highest corrosion resistance than bare SS316L and the rest coatings. Capacitance analysis shows that TiAlN-2A coated sample has lower electron donor concentration, which indicates better corrosion resistance. According to ICR results, at compaction of 1.4 MPa, the ICR value of TiAlN-2A coating is 12.6 mΩ cm2, which is close to satisfy the DOE 2020 technical targets (≤10 mΩ cm2). In addition, the corrosion and conductivity mechanism is also investigated.

Physico-chemical properties of CrMoN coatings - combined experimental and computational studies

In this study, Cr−Mo−N thin films with different Mo contents were synthesised via closed field unbalanced magnetron sputtering ion plating. The effects of Mo content on the microstructure, chemical bonding state, and optical properties of the prepared films were investigated by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy, and ultraviolet-visible spectrophotometry. XRD results determined the face centered cubic (fcc) structure of pure CrN film. The incorporation of molybdenum (Mo) in the CrN matrix was confirmed by both XRD and XPS analyses. The CrMoN coatings demonstrate various polycrystalline phases including CrN, γ-Mo2N, Cr with oxides layers of MoO3, CrO3, and Cr2O3. Microstructural results of the Cr-Mo-N coatings show that the grain size increased with an increase in Mo content due to the formation of MoN phase, in which the Mo atoms interact with N atoms around the grain boundaries of the CrN phase. XPS investigations confirmed the presence of Cr, Mo, N, C and O elements in the studied coatings. The optical results revealed that the synthesised coatings exhibit low reflection magnitudes in the visible region of the solar spectrum indicating good antireflection surfaces. Mo doped thin coatings improve the solar absorptance by ~76% in the wavelength range of 200–800 nm with a low thermal emittance of ~ 20% in the infrared range (up to 4000 nm). Furthermore, by applying density functional theory, the computational simulation provides similar trends as the experimental finding of absorption coefficient in the wavelength range.

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.

Study of the structure, properties, scratch resistance and deformation behaviour of graded Cr-CrN-Cr(1-x)AlxN coatings

An in-depth investigation of the structure, properties, scratch adhesion characteristics of graded Cr-CrN-Cr(1-x)AlxN coatings synthesized onto M42 steel substrates using closed – field unbalanced magnetron sputtering (CFUBMS) was carried out. Advanced microscopy (scanning and transmission electron microscopy), focused ion beam (FIB) imaging, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and micro–scratch tests was used to investigate the microstructure, mechanical properties and scratch performance as a function of Al content. FIB and TEM investigations revealed that the coatings exhibited a distinct structure; i.e., an adhesive Cr layer, a CrN transition layer and a graded CrAlN top layer with a face centered cubic (FCC) B1 structure. A columnar morphology was exhibited by the coatings and the dimensions of the columnar grains decreased with increasing Al content. Residual stress measurements, obtained from the XRD – sin2ψ method, revealed increasing compressive stresses with increasing Al content. Furthermore, nanoindentation tests showed an increase in mechanical properties, fracture toughness index (H/E) and plastic deformation resistance (H3/E2) as the Al content increased, accompanied by a decrease in the critical load, LC, during scratch testing implying a decrease in scratch toughness.

Microstructure, mechanical and tribological characterization of CrN/DLC/Cr-DLC multilayer coating with improved adhesive wear resistance

Adhesive wear is one of the major reasons for the failure of components during various tribological application, especially for rubbing with viscous materials. This study presents CrN/DLC/Cr-DLC multilayer composite coatings prepared on a plasma enhanced chemical vapor deposition (PECVD) device with the close field unbalanced magnetron sputtering ion plating (CFUBMSIP) technique. SEM, XRD and Raman spectroscopy were used to determine the structure of multilayer coatings. It was found that the multilayer coatings are composed by the alternating CrN and DLC layers. Compared with the single CrN coatings, the friction coefficient of the CrN/DLC/Cr-DLC multilayer coating decreases about more than seven times after sliding a distance of 500 m. This helps to reduce the adhesive wear of multilayer coatings. Compared with the single CrN and DLC coating, the wear rate of the CrN/DLC/Cr-DLC multilayer coating is reduced by an order of magnitude to 7.10 × 10−17 (sliding with AISI 440C) and 2.64 × 10−17 (sliding with TC4) m3/(N m). The improved tribological performance of multilayer coatings mainly attributes to the introduction of lubricant DLC and hard support CrN layers, the enhancement of crack propagation inhibition, and the increment of elastic recovery value We (71.49%) by multilayer design method.

The corrosion behavior and mechanical properties of CrN/Ni[sbnd]P multilayer coated mild steel as bipolar plates for proton exchange membrane fuel cells

This research mainly studies on the interfacial conductivity and corrosion resistance of mild steel (MS)/electroless plating nickel (EN)/CrN composite coating. The MS/EN/CrN composite coating is deposited on a mild steel substrate using a combination of electroless nickel plating process and closed field unbalanced magnetron sputter ion plating system. The simulative working environment of proton exchange membrane fuel cell (PEMFC) is implemented to test the electrical and corrosion properties of uncoated mild steel and coated samples. Results show that the performance of the MS/EN/CrN coated samples was greatly improved. The SEM results indicate that the surface of MS/EN/CrN is dense and smooth. CrN (111) and Ni (111) are observed in the MS/EN/CrN coating by XRD. The potentiodynamic polarization and EIS tests show that the incorporation of electroless nickel deposits into the CrN coating can provide better corrosion resistance. Potentiostatic polarization tests reveal that MS/EN/CrN coating has the lowest current density both in anodic and cathodic environment. The Interfacial contact resistance (ICR) results show that the ICR of MS/EN/CrN coated sample reduces to 3.3 mΩ cm2 at a compaction force of 140 N/cm2. Moreover, after potentiostatic polarization, the ICR values of the MS/EN/CrN coating are still less than DOE's 2020 target. In addition, compared with other samples, the hardness and adhesion property of the MS/EN/CrN multilayer coating were greatly improved, which is beneficial for resisting the shock and wear during the assembly process of fuel cell stacks.

Reactive close field unbalance magnetron sputter deposition of titanium dioxides for potential photovoltaic applications

In this paper, crystallised TiO2 thin film was produced by reactive Closed Field UnBalanced Magnetron Sputter Ion Plating. Various deposition conditions were studied, including sputtering power, oxygen partial pressure and elemental doping and their effects on the resulting titania structure were characterised. Rutile or anatase titania can be obtained selectively or in combination by properly controlling the deposition conditions, i.e. rutile structure can be obtained using one titanium target with high oxygen flow (20% OEM) and be enhanced by manganese doping, and fully anatase structure can be formed by preheating the sample with an auxiliary heater and heating the sample in the reactive sputtering process.TiO2 has a wide band gap (3.2 eV for anatase and 3.0 eV for rutile) which limits its ability to absorb the light to the ultraviolet region. N and/or Mn doping in the thin titanium dioxide films was used to narrow the band gap of TiO2 to about 2.0 eV with improved electrical properties.

Mechanisms of growth, properties and degradation of amorphous carbon films by closed field unbalanced magnetron sputtering on stainless steel bipolar plates for PEMFCs

Stainless steel bipolar plates possess good manufacturability, low costs, but inadequate interfacial conductivity and corrosion resistance in proton exchange membrane fuel cells (PEMFCs). Amorphous carbon films have been deposited on stainless steel as a function of bias voltage through closed field unbalanced magnetron sputtering ion plating system (CFUMSIP) to enhance the interfacial conductivity and corrosion resistance. Surface and cross-section morphologies, hybridization, interfacial conductivity, corrosion resistance and degradation mechanisms of a-C films were systemically investigated and results are very sensitive to the substrate bias voltage. The compactness and hybridization sp2/sp3 ratio have parabolic relation with the substrate bias voltage and the a-C film deposited with 120V has the densest cross structure and maximum sp3 percentage. Various electrochemical corrosion tests in the simulated PEMFCs cathode environment confirm the fact corrosion resistance is closely related to the film compactness and hybridization. Then a-C film prepared at bias voltage 120V has the lowest corrosion current density. The initial interfacial contact resistance (ICR) of a-C is a combination result of sp2 percentage and film compactness and the samples deposited with bias voltage 60V and 300V have much lower ICR values than DOE target. Afterwards, the ICR increase mechanism of a-C film after electrochemical corrosion tests is illustrated through Raman and XPS detection, and the results reveal that increased oxygen content adsorbed on the film surface contributes to the increase of ICR value.

Influence of Ti content on the corrosion properties and contact resistance of CrTiN coating in simulated proton exchange membrane fuel cells

CrTiN coatings with different Ti content are deposited on stainless steel 316L (SS316L) substrate as bipolar plates for proton exchange membrane fuel cells (PEMFCs) by close field unbalanced magnetron sputter ion planting (CFUBMSIP). The effect of Ti incorporation on the surface morphology, phase structure, electrochemical properties, interfacial contact resistance (ICR) and contact angle with water are investigated. Scanning electron microscope (SEM) results indicate that Ti doped coatings are compact and dense. X-ray diffraction (XRD) and nanoindentation hardness results show that Ti incorporated coatings have grain refinement and solid solution phase. From electrochemical test results, CrTiN-4A coating has the highest corrosion potential of 0.1825 V in the anodic PEMFCs environment. It also has the most stable and lowest current density both in simulated anodic and cathodic environments after potentiostatic polarization. Furthermore, electrochemical impedance spectroscopy (EIS) studies reveal that the corrosion resistance of CrTiN-4A coating is higher than other coatings and bare SS316L. ICR results show that CrTiN-4A coating has the lowest ICR of 4.57 mΩ cm2 at a compaction of 1.4 MPa before potentiometric polarization. In addition, the contact angles of CrTiN-4A coating before and after potentiostatic polarization are 109.0° and 99.5°, respectively.

Effect of Ni content on the electrical and corrosion properties of CrNiN coating in simulated proton exchange membrane fuel cell

In this paper, CrNiN coatings with various Ni content are deposited on 304ss bipolar plates by closed field unbalanced magnetron sputter ion plating from CrNi alloy targets. Simulative working environment of proton exchange membrane fuel cell (PEMFC) is applied to test the electrical and corrosion properties of uncoated 304ss and CrNiN-coated samples. The influence of Ni content on microstructure, phase structure, contact angle with water and electrochemical performance is investigated. Results show that all the coated samples significantly enhanced the corrosion resistance of the 304ss, and the CrN-coated 304ss sample without Ni has the best corrosion resistance of 153.8 and −141.9 mV in the simulated anodic and cathodic environments, respectively. Electrochemical impedance spectroscopy (EIS) studies reveal that the resistance of CrN coating is higher than that of other coated samples and 304ss in the cathodic environment. Furthermore, Interfacial contact resistance (ICR) studies revealed that CrN coating has a superior ICR of 11 mΩ cm2 at a compaction force of 160 N cm−2. In addition, the contact angle of the CrNiN coatings with water is approximately 114°, which is beneficial for water management in PEMFC. Analysis result indicates that the enhanced performance of the coated 304ss bipolar plates is related to the high film density determined by closed field unbalanced magnetron sputter ion plating, and the synergistic function of the CrNiN layered structure.