scholarly journals Roles of Graphene Additives in Optimizing the Microstructure and Properties of Ni–Cr–Graphene Coatings

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 104 ◽  
Author(s):  
Liang Meng ◽  
Qinyou Hu ◽  
Chaojian Shi ◽  
Changhai Huang
Keyword(s):  
Corrosion Resistance ◽  
Crystallite Size ◽  
Rietveld Refinement ◽  
Microstructure Evolution ◽  
Corrosion Current ◽  
Micro Hardness ◽  
Electrodeposition Technique ◽  
Graphene Coating ◽  
Order Of Magnitude ◽  
Corrosion Behaviors

The electrodeposition technique was used to fabricate graphene and Cr particle-reinforced Ni–Cr–graphene coatings. The Rietveld refinement was utilized to analyze the microstructure of Ni deposits in the coatings. The properties including micro-hardness and corrosion behaviors of the coatings were also tested. Results showed that the addition of graphene particles contributed to the dendrite like structure on the surface of the Ni–Cr–graphene coating. The crystallite size and [200] texture of the Ni deposits in the Ni–Cr–graphene coatings were significantly decreased by the graphene particles. The crystallite size of 149.8 nm in the Ni-25–Cr-0–graphene coating was reduced to 35 nm in the Ni-25–Cr-8–graphene coating due to the addition of 8 g/L graphene to the electrolyte. The microstructure evolution of the Ni–Cr–graphene coatings brought about an enhancement in micro-hardness and corrosion resistance of the coatings. The micro-hardness of the coatings was improved from 260.1 HV0.2 of the pure Ni coating to 285.9 HV0.2 of the Ni-25–Cr-0–graphene coating and continually to 461.8 HV0.2 of the Ni-25–Cr-8–graphene coating. In corrosion solution (3.5 wt.% NaCl), the corrosion current (6.22 μA/cm2) of the Ni-25–Cr-0–graphene coating could be decreased by about an order of magnitude through the addition of graphene particles, which was 0.33 μA/cm2 for the Ni-25–Cr-8–graphene coating.

scholarly journals Chemical Composition and Corrosion Behavior of a-C:H/DLC Film-Coated Titanium Substrate in Simulated PEMFC Environment

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 820
Author(s):  
Beibei Han ◽  
Mengyuan Yan ◽  
Dongying Ju ◽  
Maorong Chai ◽  
Susumu Sato
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Metal Ion ◽  
Ion Beam ◽  
Titanium Substrate ◽  
Corrosion Current ◽  
Ion Concentration ◽  
Bipolar Plates ◽  
High Adhesion ◽  
Corrosion Behaviors

The amorphous hydrogenated (a-C:H) film-coated titanium, using different CH4/H2 and deposition times, was prepared by the ion beam deposition (IBD) method, which has the advantage of high adhesion because of the graded interface mixes at the atomic level. The chemical characterizations and corrosion behaviors of a-C:H film were investigated and evaluated by SEM, AFM, Raman spectroscopy, EPMA, TEM and XPS. An a-C:H film-coated titanium was corroded at 0.8 V, 90 °C in a 0.5 mol/L H2SO4 solution for 168 h. The metal ion concentration in the H2SO4 corrosion solution and the potentiodynamic polarization behavior were evaluated. Results indicate that a higher CH4/H2 of 1:0 and a deposition time of 12 h can result in a minimum ID/IG ratio of 0.827, Ra of 5.76 nm, metal ion concentration of 0.34 ppm in the corrosion solution and a corrosion current of 0.23 µA/cm2. The current density in this work meets the DOE’s 2020 target of 1 µA/cm2. Electrical conductivity is inversely proportional to the corrosion resistance. The significant improvement in the corrosion resistance of the a-C:H film was mainly attributed to the increased sp3 element and nanocrystalline TiC phase in the penetration layer. As a result, the a-C:H film-coated titanium at CH4/H2 = 1:0 with improved anti-corrosion behavior creates a great potential for PEMFC bipolar plates.

Influence of EDTA-2Na Concertration on the Microstructure and Corrosion Behaviors of Mg-Al-Y Alloy

2015 ◽  
Vol 727-728 ◽  
pp. 201-204
Author(s):  
Yun Long Zhang ◽  
Mu Qin Li ◽  
Ping Liao ◽  
Yu Min Zhang
Keyword(s):  
Corrosion Resistance ◽  
Electrolyte Solution ◽  
Oxidation Process ◽  
Corrosion Current ◽  
Positive Potential ◽  
Micro Arc Oxidation ◽  
Corrosion Behaviors ◽  
Oxidation Technology ◽  
Structural Surface ◽  
Polarisation Measurements

In this paper,the micro-arc oxidation technology were utilized to fabricated the oxidation coating in order to resolve the corrosion resistance of the Mg-Al-Y alloy. The EDTA-2Na solution was introduced into the electrolyte solution for improving the coating corrosion properties.After the micro-arc oxidation process, phase structural, surface morphology and corrosion resistance of the MAO coating of Mg-Al-Y alloy were performed by XRD, SEM and Potentiodynamic polarisation measurements. The introduce of EDTA-2Na in the electrolyte solution improve the positive potential and reduced the corrosion current, which would improve the corrosion resistance properties of the Mg-Al-Y alloy.

EFFECT OF TiO2 PARTICLES ON MICRO-HARDNESS, CORROSION, WEAR AND FRICTION OF Ni–P–TiO2 COMPOSITE COATINGS AT DIFFERENT ANNEALING TEMPERATURES

2016 ◽  
Vol 23 (01) ◽  
pp. 1550082 ◽  
Author(s):  
PRASANNA GADHARI ◽  
PRASANTA SAHOO
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Composite Coatings ◽  
Corrosion Current ◽  
Xrd Analysis ◽  
Charge Transfer Resistance ◽  
Micro Hardness ◽  
Transfer Resistance ◽  
X Ray ◽  
Annealing Temperatures

The present study investigates the effect of titania particles on the micro-hardness, wear resistance, corrosion resistance and friction of electroless Ni–P–TiO2 composite coatings deposited on mild steel substrates at different annealing temperatures. The experimental results confirmed that the amount of TiO2 particles incorporated in the coatings increases with increase in the concentration of particles in the electroless bath. In presence of TiO2 particles, hardness, wear resistance and corrosion resistance of the coating improve significantly. At higher annealing temperature, wear resistance increases due to formation of hard Ni3P phase and incorporation of titania particles in the coated layer. Charge transfer resistance and corrosion current density of the coatings reduce with an increase in TiO2 particles, whereas corrosion potential increases. Microstructure changes and composition of the composite coating due to heat treatment are studied with the help of scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA) and X-ray diffraction (XRD) analysis.

Influence of SiC Content and Heat Treatment on the Corrosion Resis-Tance and Oxidation Resistance of Ni-P-SiC Composite Coating

2015 ◽  
Vol 817 ◽  
pp. 479-483
Author(s):  
Pan Li ◽  
Wan Chang Sun ◽  
Jun Gao ◽  
Quan Zhou ◽  
Pei Zhang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Composite Coating ◽  
Oxidation Resistance ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Treatment Temperature ◽  
Micro Hardness ◽  
Resis Tance ◽  
P Matrix

Ni-P alloy and SiC micron particles were codeposited on Q235 steel by electroless plating. The composition, microstructure, micro-hardness, corrosion resistance and oxidation resistance of the composite coating were studied. The results revealed that the deposited composite coating shows dispersed SiC particles and continuous Ni-P matrix. When the content of SiC was 8g/L and the heat treatment temperature was 300°C, the corrosion potential and corrosion current of Ni-P-SiC coating were-0.292V, and 8.2×10-7 A/cm2, respectively, while those of Ni-P composite coating were-0.501V, and 4.2×10-5 A/cm2, respectively. Ni-P-SiC composite coating with high content of SiC exhibits better oxidation resistance than Ni-P coating.

Effects of Y Alloying on Thermal Stability and Corrosion Resistance of Cu-Zr-Al Metallic Glass

2013 ◽  
Vol 850-851 ◽  
pp. 62-65
Author(s):  
Yi Liu ◽  
Yan Fang Wang ◽  
Li Jun Xiao ◽  
Ming Xing Liu ◽  
Zhi Qiang Shi
Keyword(s):  
Thermal Stability ◽  
Corrosion Resistance ◽  
Base Alloy ◽  
Amorphous State ◽  
Corrosion Current ◽  
Casting Method ◽  
Glass Forming ◽  
Minor Addition ◽  
Corrosion Behaviors ◽  
Thermal Stability Of

The (Cu50Zr45Al5)100-XYX(x=0, 1, 2, and 3) alloys samples were prepared by copper mold suction casting method. The effect of the addition of Y on the structure, glass-forming ability, thermal stability and corrosion behaviors of the base BMG (Cu50Zr45Al5) were investigated by means of XRD, DSC, DTA and electrochemical polarization. The results showed that Cu10Zr7and Zr2Cu phases are precipitated when Y addition exceeds 3at%, otherwise the alloys are fully amorphous state. Minor addition Y improved the thermal stability of the base alloy. The corrosion resistance of BMG alloy is deteriorated in 3.5% NaCl solution with addition of Y element as indicated by the corrosion potential and corrosion current density.

scholarly journals The Tribocorrosion and Corrosion Properties of Thermally Oxidized Ti6Al4V Alloy in 0.9 wt.% NaCl Physiological Saline

Coatings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 285 ◽  
Author(s):  
Lei Cao ◽  
Yong Wan ◽  
Shuyan Yang ◽  
Jibin Pu
Keyword(s):  
Oxide Layer ◽  
Physiological Saline ◽  
Corrosion Current ◽  
Rutile Phase ◽  
Micro Hardness ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Material Loss ◽  
Air Atmosphere ◽  
Order Of Magnitude

Thermal oxidation of Ti6Al4V was carried out at 700 °C for 5 h in air atmosphere. The characteristics of morphology and structure, micro-hardness, and tribocorrosion behavior in 0.9 wt.% NaCl solution of thermally oxidized Ti6Al4V alloys were investigated and compared with those of the untreated one. The scanning electron microscope (SEM) and glow discharge spectrometer (GDS) results reveal that the oxide layer is completely coated on the substrate, which is a bilayer structure consisted of oxide film and oxygen diffusion zone (ODZ). X-ray diffraction (XRD) and Raman measurements reveal the rutile phase as the dominant phase. The micro-hardness and surface roughness (Ra) increase about 1.63 and 4 times than those of the untreated one. Thermally oxidized sample obtains corrosion and tribocorrosion resistance property in 0.9 wt.% NaCl solution. The corrosion potential has a more than 500 mV anodic shift, the corrosion current density decreases about 80%. The total material loss volume is reduced by almost an order of magnitude under tribocorrosion behavior, which is due to the improvement of the micro-hardness of the oxide layer and ODZ that reduce the corrosion and the synergistic effect of corrosion and wear.

scholarly journals Selective Laser Melting of 316L Stainless Steel: Influence of Co-Cr-Mo-W Addition on Corrosion Resistance

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 597
Author(s):  
Bolin Li ◽  
Tingting Wang ◽  
Peizhen Li ◽  
Shenghai Wang ◽  
Li Wang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Selective Laser Melting ◽  
Scanning Speed ◽  
Corrosion Current ◽  
Laser Melting ◽  
Two Samples ◽  
Order Of Magnitude ◽  
The Difference ◽  
Tensile Experiment

The selective laser melting (SLM) of o-Cr-Mo-W/316L composite with 10wt% Co-Cr-Mo-W addition to 316 L stainless steel (SS) powder is produced to explore it’s the corrosion behavior. The tensile experiment of SLM composites is also measured to investigate the difference between the two samples. The optimum parameters of SLM 316 L SS and it’s composite samples are obtained by adjusting laser power and scanning speed with the relative density of 99.04 ± 0.69 and 99.15 ± 0.43. The yield strength of samples is increased from 731.96 MPa to 784.09 MPa after doping, and no obvious crack or fracture failure in the tensile samples are observed, indicating that the excellent plasticity is still maintained. The corrosion resistance of samples is improved largely with an order of magnitude lower corrosion current density than that of 316 L SS and increasing of 277 mv of epit Ep. The addition of Cr element in the doped powder contributes to the formation of the passivated film containing Cr. The different pitting corrosion pit occurs mainly around the pre-existing pores of the powder and further extends outward to form pits with the increase of voltage.

scholarly journals Effects of the Combined Addition of Zn and Mg on Corrosion Behaviors of Electropainted AlSi-Based Metallic Coatings Used for Hot-Stamping Steel Sheets

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3379
Author(s):  
Si On Kim ◽  
Won Seog Yang ◽  
Sung Jin Kim
Keyword(s):  
Corrosion Resistance ◽  
Hot Stamping ◽  
Electrochemical Techniques ◽  
Corrosion Current ◽  
Selective Dissolution ◽  
Localized Corrosion ◽  
Steel Sheets ◽  
Corrosion Behaviors ◽  
Automotive Steel ◽  
Hot Stamping Steel

The effects of the combined addition of Zn and Mg on the corrosion resistance of AlSi-based coating for automotive steel sheets were investigated using a variety of analytical and electrochemical techniques. The preferential dissolution of Mg and Zn from MgZn2/Mg2Si phases occurred on the AlSi-based coating that had been alloyed with a smaller portion of Zn and Mg, which contributed to the rapid surface coverage by corrosion products with a protective nature, reducing the corrosion current density. On the other hand, localized corrosion attacks caused by the selective dissolution of Mg were also observed in the AlSi-based coating with a smaller portion of Zn and Mg. Such alloying can also worsen its corrosion resistance when coated additionally with electrodeposited paint. The mechanistic reasons for these conflicting results are also discussed.

scholarly journals Effect of CeO2 on Corrosion Resistance of High-Current Pulsed Electron Beam Treated Pressureless Sintering Al-20SiC Composites

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 707
Author(s):  
Yue Sun ◽  
Bo Gao ◽  
Liang Hu ◽  
Kui Li ◽  
Ying Zhang
Keyword(s):  
Corrosion Resistance ◽  
Electron Beam ◽  
Rare Earth ◽  
Corrosion Current ◽  
Corrosion Mechanism ◽  
Pressureless Sintering ◽  
Electron Beam Treatment ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Order Of Magnitude

In this paper, the effect of rare earth Ce on the corrosion resistance of Al-20SiC composites treated with high-current pulsed electron beams is investigated, and the corresponding corrosion mechanism is proposed. The scanning electron microscope (SEM) results show that cracks arise on the surface of Al-20SiC composites prepared by pressureless sintering. After electron beam treatment, the pores on the surface are reduced because of the filling of Al liquid. After adding CeO2 to Al-20SiC composites, the wettability between Al and SiC phases is improved, thus realizing metallurgical bonding of the two phases, and microcracks generated after HCPEB treatment are significantly eliminated. Glancing X-ray diffraction (GIXRD) results show that after electron beam treatment, aluminum grains tend to grow more favorably with the stable and dense crystal plane of Al(111), thus improving corrosion resistance. The electrochemical test results show that the corrosion current density decreases by one order of magnitude with increase in the number of pulses because of rare earth Ce compared to the initial Al-20SiC composite specimens, indicating that the corrosion resistance of the Al-20SiC-0.3CeO2 composite is improved. This is because rare earth not only eliminates microcracks, but also changes the type of corrosion from localized to uniform, thus improving corrosion resistance. The Al-based composite material modified by electron beam and rare earth has many potential applications and development prospects.

Influence of HF-SCG Immersion Treatment on Corrosion Resistance of the Ultrasonic Micro-Arc Oxidation Bio-Coating on Pure Magnesium

2014 ◽  
Vol 633 ◽  
pp. 402-405
Author(s):  
Mu Qin Li ◽  
Jiang Liu ◽  
Jun Gang Li ◽  
Ding Sen Cai ◽  
Yong Hui Zhao
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Ceramic Coatings ◽  
Pure Magnesium ◽  
Electrolyte System ◽  
Order Of Magnitude ◽  
Micro Arc Oxidation ◽  
Compound Coatings

Ceramic coatings were fabricated on pure magnesium in silicate electrolyte system by ultrasonic micro-arc oxidation (UMAO) process, and then silica sol (CSG) and HF-CSG treatment were carried out on micro-arc oxidation coatings. The corrosion potential (Ecorr) and corrosion current density (Icorr) of the compound coatings were analyzed by electrochemical corrosion workstation. The corrosive morphology of the coatings was observed by scanning electron microscopy (SEM). Results showed that the Ecorr of the coating with CSG and HF-CSG treatment increased by 55 mV and 69 mV respectively in comparison with that of single UMAO coating, and its Icorr reduced an order of magnitude, which had enhanced the corrosion resistance.

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