Ti/(Ti,Cr)N/CrN multilayer coated 316L stainless steel by arc ion plating as bipolar plates for proton exchange membrane fuel cells

Arc ion plating (AIP) is applied to form Ti/(Ti,Cr)N/CrN multilayer coating on the surface of 316L stainless steel (SS316L) as bipolar plates for proton exchange membrane fuel cells (PEMFCs). The characterizations of the coating are analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Interfacial contact resistance (ICR) between the coated sample and carbon paper is 4.9 m Omega cm(2) under 150 N/cm(2), which is much lower than that of the SS316L substrate. Potentiodynamic and potentiostatic tests are performed in the simulated PEMFC working conditions to investigate the corrosion behaviors of the coated sample. Superior anticorrosion performance is observed for the coated sample, whose corrosion current density is 0.12 mu A/cm(2). Surface morphology results after corrosion tests indicate that the substrate is well protected by the multilayer coating. Performances of the single cell with the multilayer coated SS316L bipolar plate are improved significantly compared with that of the cell with the uncoated SS316L bipolar plate, presenting a great potential for PEMFC application. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Formation of nanocrystalline microstructure in arc ion plated CrN films

Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.

Wave Attenuation Performance and the Influencing Factors of A Lower Arc-Plate Breakwater

Comprehensive experimental and numerical studies have been undertaken to investigate wave energy dissipation performance and main influencing factors of a lower arc-plate breakwater. The numerical model, which considers nonlinear interactions between waves and the arc-plate breakwater, has been constructed by using the velocity wave- generating method, the volume of fluid (VOF) method and the finite volume method. The results show that the relative width, relative height and relative submergence of the breakwater are three main influencing factors and have significant influence on wave energy dissipation of the lower arc-plate open breakwater. The transmission coefficient is found to decrease with the increasing relative width, and the minimum transmission coefficient is 0.15 when the relative width is 0.45. The reflection coefficient is found to vary slightly with the relative width, and the maximum reflection coefficient is 0.53 when the relative width is 0.45. The transmission and reflection coefficients are shown to increase with the relative wave height for approximately 85% of the experimental tests when the relative width is 0.19 0.45. The transmission coefficients at relative submergences of 0.04, 0.02 and 0 are clearly shown to be greater than those at relative submergences of 0.02 and 0.04, while the reflection coefficient exhibits the opposite relationship. After the wave interacts with the lower arc-plate breakwater, the wave energy is mainly converted into transmission, reflection and dissipation energies. The wave attenuation performance is clearly weakened for waves with greater heights and longer periods.

Friction and Wear Performances of Cathodic Arc Ion Plated TiAlSiN Coating under Oil Lubricated Condition

TiAlSiN coating was deposited on H13 hot work mould steel using cathodic arc ion plating（CAIP）. The surface-interface morphologies and phases of the obtained coating were analyzed using field emission scanning electron microscopy（FESEM） and X-ray diffraction（XRD）, respectively, and the morphologies, distributions of chemical elements and profiles of worn tracks were also researched using scanning electron microscopy（SEM）, energy disperse spectroscopy（EDS）, and optical microscope（OM）, respectively. The friction-wear performances of TiAlSiN coating under oil lubricated and dry fiction conditions were investigated, and the wear mechanisms of TiAlSiN coating were discussed. The experimental results show that the coating is primarily composed of（Ti, Al）N, AlTiN, and TiN hard phases, Si_3N_4 exists between the（Ti, Al）N crystal grains, increasing the coating microhardness to 3200 HV. The TiAlSiN coating has excellent performances of reducing friction and wear resistance, the average coefficient of friction（COF） of TiAlSiN coating under oil lubricated condition is only 0.05, lowered than the average COF of 0.211 under dry friction condition, the wear rate decreases by about 81.2% compared with that under dry friction condition. The wear mechanism of TiAlSiN coating under oil lubricated and dry friction conditions is composed of abrasive wear, fatigue wear, and abrasive wear, respectively. The internal friction of oil lubrication is a main factor of decreasing fatigue wear.

Study on Submerged Upper Arc-Shaped Plate Type Breakwater

Based on the wave radiation and diffraction theory, this paper investigates a new type breakwater with upper arcshaped plate by using the boundary element method(BEM). By comparing with other three designs of plate type breakwater(lower arc-shaped plate, single horizontal plate and double horizontal plate), this new type breakwater has been proved more effective. The wave exiting force, transmission and reflection coefficients are analyzed and discussed. In order to reveal the wave elimination mechanism of this type of breakwater, the velocity field around the breakwater is obtained. It is shown that:(1) The sway exciting force is minimal.(2) When the ratio of the submergence and wave amplitude is 0.05, the wave elimination effect will increase by 50% compared with other three types of breakwater.(3) The obvious backflow is found above the plate in the velocity field analysis.

Gas metal arc welding of duplex stainless clad steel plates

The 2205 duplex stainless ＋ DH36 clad steel plate was welded by gas metal arc welding（GMAW）, and the welding performance of the clad steel plate was investigated. The results show that the adaptability of the welding procedure for the base metal of carbon steel, the transition layer, and the cladding material is excellent. The test results indicate that the phase proportion and component dilution of the GMAW-welded joints of clad steel plate can be effectively controlled to yield joints with good mechanical properties and corrosion resistance.

Microstructure and mechanical properties of TiN/TiAlN multilayer coatings deposited by arc ion plating with separate targets

TiN/TiAlN multilayer coatings were prepared by arc ion plating with separate targets. In order to decrease the unfavorable macroparticles, a straight magnetized filter was used for the low melting aluminium target. The results show that the output plasmas of titanium target without filter and aluminium target with filter reach the substrate with the same order of magnitude. Meanwhile, the number of macropartieles in TiN/TiAlN multilayer coatings deposited with separate targets is only 1/10-1/3 of that deposited with alloy target reported in literature. Al atom addition may lead to the decrease of peak at （200） lattice plane and strengthening of peak at （111） and （220） lattice planes. The measured hardness of TiN/TiAlN multilayer coatings accords with the mixture principle and the maximum hardness is HV2495. The adhesion strength reaches 75 N.

Effect of Rare Earth Element Cerium on Mechanical Properties and Morphology of TiN Coating Prepared by Arc Ion Plating

TiN coatings were deposited on polished substrates of W18Cr4V high speed steel by means of vacuum arc ion plating. The effect of cerium on adhesion between TiN coating and substrate was studied. The microstructures and composition of TiN coatings were also investigated by means of scanning electron microscope (SEM), Auger electron spectroscopy (AES), and X ray diffraction (XRD) technique. It was found that cerium is an effective modifying agent and the addition of suitable amount of cerium to TiN coatings can produce relatively excellent properties such as micro hardness, wear resistance, oxidation resistance and porosity. The experimental results show that the added cerium in TiN coatings makes a contribution to form the preferred direction along with a (111) or (222) close packed face, which may be one of the reasons that improves some properties mentioned above.

Experimental Verification of the Physical Model for Droplet-Particles Cleaning in Pulsed Bias Arc Ion Plating

It has been reported that application of pulsed biases in arc ion plating could effectively eliminate droplet particles. The present paper aims at experimental verification of a physical model proposed previously by us which is based on particle charging and repulsion in the pulsed plasma sheath. An orthogonal experiment was designed for this purpose, using the electrical parameters of the pulsed bias for the deposition of TiN films on stainless steel substrates. The effect of these parameters on the amount and the size distribution of the particles were analyzed, and the results provided sufficient evidence for the physical model.

Microstructure and residual stress of TiN films deposited at low temperature by arc ion plating

The TiN films were deposited on 316 L stainless steel substrates at low temperature by arc ion plating. The influences of substrate bias voltage and temperature on microstructure, residual stress and mechanical properties of the films were investigated by EDS, SEM, XRD and nanoindenter tester, respectively. The results showed that the TiN films were highly oriented in（111） orientation with a face-centered cubic structure. With the increase of substrate bias voltage and temperature, the diffraction peak intensity increased sharply with simultaneous peak narrowing, and the small grain sizes increased from 6.2 to 13.8 nm. As the substrate temperature increased from 10 to 300℃, the residual compressive stress decreased sharply from 10.2 to 7.7 GPa, which caused the hardness to decrease from 33.1 to 30.6 GPa, while the adhesion strength increased sharply from 9.6 to 21 N.

THE EFFECTS OF PULSE BIAS VOLTAGE AND N_2 PARTIAL PRESSURE ON TiAlN FILMS OF ARC ION PLATING (AIP)

Owing to the characteristics of arc ion plating(AIP) technique, the structure and composition of TiAlN films can be tailored by controlling of various parameters such as compositions of target materials, N2 partial pressure, substrate bias and so on. In this study, several titanium aluminum nitride films were deposited on 1Cr11Ni2W2MoV steel for compressor blade of areo-engine under different d.c pulse bias voltage and nitrogen partial pressure. The effects of substrate pulse bias and nitrogen partial pressure on the deposition rate, droplet formation, microstruture and elemental component of the films were investigated.

Composition demixing effect on cathodic arc ion plating

The composition demixing effect has been found often in alloy coatings deposited by cathodic arc ion plating using various alloy cathode targets. The characteristics of composition demixing phenomena were summarized. Beginning with the ionization zone near the surface of the cathode target, a physical model in terms of the ions generated in the ionization zone and their movement in the plating room modified by bias electric field was proposed. Based on the concept of electric charge state, the simulation calculation of the composition demixing effect was carried out. The percentage of atoms of an element in coating and from the alloy target was demonstrated by direct comparison. The influences of the composition change of the alloy target and the bias electric field on the composition demixing effect were discussed in detail. It is also proposed that the average charge states of the elements may be used to calculate the composition demixing effect and to design the composition of the alloy target.

STUDY ON HIGH TEMPERATURE PERFORMANCES OF MCrAlX COATINGS DEPOSITED BY MULTI-ARC ION PLATING

NCoCrAlSiYHf and CoNiCrAlTaY coatings which belong to protective Al 2O 3 scale forming type were deposited by multi arc ion plating technique . The effect of deposition process parameters on qualities of the coatings was discussed. The high temperature oxidation performances isothermal oxidation with 950℃ / 500h and 1100℃ / 100h were studied. And also, the hot corrosion performances at 700℃ and 800℃, with molten mixed salt composed of 75%wt Na 2SO 4 and 25%wt NaCl were investigated. Then the high temperature protection decaying mechanisms were proposed.

Influences of nitrogen flow rate on the structures and properties of Ti and N co-doped diamond-like carbon films deposited by arc ion plating

In this paper, Ti-C-N nanocomposite films are deposited under different nitrogen flow rates by pulsed bias arc ion plating using Ti and graphite targets in the Ar/N2 mixture gas. The surface morphologies, compositions, microstructures, and mechanical properties of the Ti-C-N films are investigated systematically by field emission scanning electron mi- croscopy （FE-SEM）, x-ray photoelectron spectroscopy （XPS）, grazing incident x-ray diffraction （GIXRD）, Raman spectra, and nano-indentation. The results show that the nanocrystalline Ti（C,N） phase precipitates in the film from GIXRD and XPS analysis, and Raman spectra prove the presence of diamond-like carbon, indicating the formation of nanocomposite film with microstructures comprising nanocrystalline Ti（C,N） phase embedded into a diamond-like matrix. The nitrogen flow rate has a significant effect on the composition, structure, and properties of the film. The nano-hardness and elastic modulus first increase and then decrease as nitrogen flow rate increases, reaching a maximum of 34.3 GPa and 383.2 GPa, at a nitrogen flow rate of 90 sccm, respectively.

Geology and Genesis of Peraluminous Granites in East Tianshan Upper Paleozoic Island Arc Belt

A peraluminous granite belt occurs along the connecting zone between the TurPan-Hami Precambrian block and the Upper Paleozoic island arc belt. Muscovite granite and two-mica granite are the essential lithological components of that belt. All the potassium feldspars inthese granites are microcline. Heavy minerals are dominated by magnetite. SiO2 contents ofthese granites are greater than 73 % with most of the A/NKC values greater than 1.1, norma-tive corundum values greater than 1. Plots of CIPW norms in the (AL-K-Na)-Ca-(Fe2++ Mg)diagram are mostly situated in the plagioclase-cordierite-muscovite region. The rocks are char-acterized by very low contents of minor elements and ΣREE with strong Eu depletion, δ18Ovalues between 6. 69‰ and 7. 0‰, Rb-Sr isochron age of 260. 2 ± 6. 2 Ma and an initial 87Sr/86Sr ratio of 0. 7052. These granites might have been produced by partial melting of moderatelyacidic volcanites and low-maturity sediments in the basement sequences and could be geneticallyconnected with the southward A-type subduction of the Turpan-Hami block following the clo-sure of the Middle Carboniferous back-arc basin.

Effect of deposition parameters on mechanical properties of TiN films coated on 2A12 aluminum alloys by arc ion plating (AIP)

TiN films were deposited on 2A12 aluminum alloy by arc ion plating (AIP). The Vickers hardness of the films deposited at different bias voltages and different nitrogen gas pressures, and that of the substrate were measured. The surface roughness of the TiN films diposited at –30 V and –80 V respectively and at different nitrogen gas pressure was measured also. The mass loss of TiN films deposited at 0 V, –30 V and –80 V respectively were analyzed in dry sand rubber wheel abrasive wear tests and wet ones in comparison with uncoated Al alloy and austenitic stainless steel (AISI 316L). It is revealed that the highest hardness of the TiN film is obtained at a bias voltage of –30 V and a N2 gas pressure of 0.5 Pa. The surface roughness of the film is larger at –80 V than that at –30 V and reduces as the increase of the N2 gas pressure. The mass loss of TiN-film coated 2A12 aluminum alloy is remarkably less than that of uncoated Al alloy and also that of AISI 316L, which indicates that the abrasive wear rate is greatly reduced by the application of TiN coating. TiN coating deposited by arc ion plating (AIP) technique on aluminum alloy can be a potential coating for machine parts requiring preciseness and lightness.

EXPERIMENTAL STUDY ON SUPERFICIAL COAT OF GEARS OF NITRIDED 32Cr2MoV COATED WITH TiN FILM BY MULTI-ARC ION PLATING

After 32CrMoV is selected to manufacture nitrided gears coated with TiN by multi-arc ion plating, all of these uncoated gears and coated gears run in the gearbox under the same initial conditions so as to compare their difference concerning properties and microstructure. Experiment results indicate that tooth surface of the coated-TiN gears does not suffer surface abnormalities in meshed zone. Instead, the gears with nitrided case exhibit an abrasion mark on the meshed zone of tooth surface, which results in more weight loss of nitrided gears. The morphology of the surface suggests TiN film with more than 2 000 HV is so dense and smooth that coated-TiN gears have higher wear resistance compared with the uncoated gears. The microstructure of coated-TiN gears is finer, hardness is higher and its distribution of coated-TiN gears is more reliable than uncoated ones, which makes nitride layer combined with TiN film tightly. Consequently, the wear-resistance of gears has been dramatically promoted.

工程机械厚板高强钢D-Arc高效焊接工艺

采用D-Arc焊接方法对工程机械用Q690D厚板开展了对接和T形接头进行焊接试验,对焊接试样的焊缝成形、显微组织和显微硬度进行了分析,并开展了拉伸、弯曲和冲击的力学性能测试。结果表明,25 mm板厚对接接头和30 mm T形接头采用D-Arc焊接技术,相对于常规气保焊,不仅焊接道数少1/3以上,且熔深明显增大,焊缝成形美观。在较大的焊接电流参数下,微观组织没有出现异常的粗化,热影响区最高硬度和软化区的最低硬度与母材的硬度相比,未出现异常。拉伸性能、弯曲性能和冲击性能测试均合格。

High temperature oxidation behavior of (Ti, Al)N coating deposited by arc ion plating

(Ti, Al)N gradient nano-coating was deposited on the surface of 1Cr11Ni2W2MoV stainless steel by the MTP-8-800 arc ion plating equipment. And the oxidation performance at high temperature for 500h was tested under the condition of the surrounding air temperature 700℃. The test results show that, because of the structural features of the （Ti, Al）N coating, the coating becomes the compact and continuous Al2O3 film, which can protect the basis material effectively in the process of the high temperature oxidizing. The oxidation kinetics of the coating accord with parabolic law.