Carbon based coating on steel with improved electrical conductivity

Graphene and graphite were coated on steel plates by means of Electro Phoresis Deposition (EPD) for electrical conductivity improvement. Thermal treatment was used after EPD to improve the adhesion between the coating layer and the steel substrate. The highest value of the electrical conductivity achieved was 20 times higher than that of the steel substrate. The optimized EPD and thermal treatment conditions were identified. The coating-steel interface and surface structure suggested that good bonding between the coating and the steel substrate was achieved

The capability of graphene on improving the electrical conductivity and anti-corrosion properties of Polyurethane coatings

Graphite and graphene particles were used to reinforce the electrical conductivity and anti-corrosion properties of polyurethane (PU) coatings. The effect of graphite and graphene were compared. Hybrid filler using carbon nanotube was adopted as well and the performance in electrical conductivity was much superior to single filler system. At the same filler loading, the electrical conductivity of hybrid filler system was significantly higher than single filler system (0.77 S/m at 5 wt% while single filler system was not conductive). The conductive mechanism was revealed. In terms of anti-corrosion properties, the coatings with low filler loading had better anti-corrosion properties. The resistance values obtained from EIS (Electrochemical Impedance Spectroscopy) and four point probe method were compared and discussed

Anodized steel electrodes for supercapacitors

Steel was anodized in 10 M NaOH to enhance its surface texture and internal surface area for application as an electrode in supercapacitors. A mechanism was proposed for the anodization process. Field-emission gun scanning electron microscopy (FEGSEM) studies of anodized steel revealed that it contains a highly porous sponge like structure ideal for supercapacitor electrodes. X-ray photoelectron spectroscopy (XPS) measurements showed that the surface of the anodized steel was Fe2O3, whereas X-ray diffraction (XRD) measurements indicated that the bulk remained as metallic Fe. The supercapacitor performance of the anodized steel was tested in 1 M NaOH and a capacitance of 18 mF cm-2 was obtained. Cyclic voltammetry measurements showed that there was a large psueudocapacitive contribution which was due to oxidation of Fe to Fe(OH)2 and then further oxidation to FeOOH, and the respective reduction of these species back to metallic Fe. These redox processes were found to be remarkably reversible as the electrode showed no loss in capacitance after 10000 cycles. The results demonstrate that anodization of steel is a suitable method to produce high-surface-area electrodes for supercapacitors with excellent cycling lifetime

Electroless Co-P-Carbon Nanotube composite coating to enhance magnetic properties of grain-oriented electrical steel

The effect of Co–P-CNT coating on the magnetic properties of grain oriented electrical steel was investigated. To analyse the coating, Raman spectroscopy, Superconducting QUantum Interference Device (SQUID), single strip testing, Scanning Electron Microscopy (SEM) and talysurf surface profilometry were performed. Raman spectra showed the D and G band which corroborates the presence of Multi-Walled Carbon Nanotubes (MWCNT) in the coating. The magnetic nature of the coating was confirmed by SQUID results. Power loss results show an improvement ranging 13–15% after coating with Co–P-CNT. The resistivity of the coating was measured to be 104 µΩ cm. Loss separation graphs were plotted before and after coating to study the improvement in power loss. It was found that the coating helps in reducing the hysteresis loss. The thickness of the coating was found to be 414±40 nm. The surface profilometry results showed that the surface roughness improved after coating the sample

Growth of carbon nanotubes from waste blast furnace gases at atmospheric pressure

Carbon emissions from industrial sources are of major global concern, especially contributions from the steel manufacturing process which accounts for the majority of emissions. Typical blast furnace gases consist of CO2 (20-25%), CO (20-25%), H2 (3-5%) and N2 (40-50%) and trace amounts of other gases. It is demonstrated that gas mixtures with these compositions can be used at atmospheric pressure to grow carbon nanotubes (CNTs) by chemical vapor deposition (CVD) on to steel substrates, which act as catalysts for CNT growth. Computational modelling was used to investigate the CNT growth conditions inside the CVD chamber. The results show that industrial waste pollutant gases can be used to manufacture materials with significant commercial value, in this case CNTs

The capability of graphene on improving the electrical conductivity and anti-corrosion properties of Polyurethane coatings

This paper was accepted for publication in the journal Applied Surface Science and the definitive published version is available at http://dx.doi.org/10.1016/j.apsusc.2017.02.081Graphite and graphene particles were used to reinforce the electrical conductivity and anti-corrosion properties of polyurethane (PU) coatings. The effect of graphite and graphene were compared. Hybrid filler using carbon nanotube was adopted as well and the performance in electrical conductivity was much superior to single filler system. At the same filler loading, the electrical conductivity of hybrid filler system was significantly higher than single filler system (0.77 S/m at 5 wt% while single filler system was not conductive). The conductive mechanism was revealed. In terms of anti-corrosion properties, the coatings with low filler loading had better anti-corrosion properties. The resistance values obtained from EIS (Electrochemical Impedance Spectroscopy) and four point probe method were compared and discussed

Graphene-based conductive coatings

Various in composition and forms, steel have been applied in many different applications such as automotive shell, supporting column and tableware. Graphene, a new era material, has many extraordinary properties such as high tensile strength, high electrical conductivity and barrier properties. It is a very promising material to be utilized as coating to improve a wide range of properties no matter applied as composite or pristine form. Electrophoresis deposition (EPD) has been received increasing interest due to its simplicity and cost effectiveness. Graphene coating layer was deposited by EPD on steel substrates for improved electrical conductivity. Graphene/polyurethane (PU) coatings on steel were prepared as well

Electroless plating: a versatile technique to deposit coatings on electrical steel

Coatings on grain-oriented electrical steel (GOES) are produced primarily by roller coating deposition of aluminium ortho phosphate on top of forsterite. These coatings provide the insulation resistance and stress to improve magnetic properties. Electroless deposition of nickel and cobalt based coatings could be used as an alternative because these coatings can be made insulated and stress can be generated and tailored in these coatings. The rate of deposition in electroless plating is faster when compared to other chemical coating techniques and the process is auto catalytic (no external current required). The coatings are corrosion resistant and the magnetic properties of the coatings can be varied by simply changing the pH of the solution. Addition of alloying elements like phosphorus and boron can manipulate the stress generated in the coating from tensile to compressive and vice versa. A 2.15 ± 0.15 μm thick Co-Ni-P coating on GOES was able to reduce the power loss by 9-11 %. Similarly a 414 ± 40 nm thick coating of Co-P-Carbon Nanotube on GOES was able to reduce the power losses ranging 13-15%.The reduction in power loss in Co-Ni-P coated sample was due to tensile stress applied on GOES by the coating which reduced the anomalous loss. The surface roughness was improved for both the Co-Ni-P and Co-P-Carbon Nanotube coating. An improvement in the surface roughness contributed to reduction of hysteresis loss

CrAlN coating to enhance the power loss and magnetostriction in grain oriented electrical steel

Grain oriented electrical steels (GOES) are coated with aluminium orthophosphate on top of a forsterite (Mg2SiO4) layer to provide stress and insulation resistance to reduce the power loss and magnetostriction. In this work Chromium Aluminium Nitride (CrAlN) was coated on GOES samples with electron beam physical vapour deposition and was tested in the single strip and magnetostriction tester to measure the power loss and magnetostriction before and after coating. Power loss was reduced by 2% after coating and 6 % post annealing at 800 °C. For applied compressive stress of 6 MPa, the magnetostrictive strain was zero with the CrAlN coating as compared to 22 and 24 μϵ for fully finished GOES and GOES without phosphate coating. The thickness of the coating was found to be 1.9 ± 0.2 μm estimated with Glow Discharge Optical Emission Spectroscopy (GDOES). The magnetic domain imaging showed domain narrowing after coating. The reduction in power loss and magnetostriction was due to the large residual compressive stress and Young’s modulus (270 GPa) of the coating

Anodized Steel Electrodes for Supercapacitors

Steel was anodized in 10 M NaOH to enhance its surface texture and internal surface area for application as an electrode in supercapacitors. A mechanism was proposed for the anodization process. Field-emission gun scanning electron microscopy (FEGSEM) studies of anodized steel revealed that it contains a highly porous sponge like structure ideal for supercapacitor electrodes. X-ray photoelectron spectroscopy (XPS) measurements showed that the surface of the anodized steel was Fe₂O₃, whereas X-ray diffraction (XRD) measurements indicated that the bulk remained as metallic Fe. The supercapacitor performance of the anodized steel was tested in 1 M NaOH and a capacitance of 18 mF cm^–2 was obtained. Cyclic voltammetry measurements showed that there was a large psueudocapacitive contribution which was due to oxidation of Fe to Fe­(OH)₂ and then further oxidation to FeOOH, and the respective reduction of these species back to metallic Fe. These redox processes were found to be remarkably reversible as the electrode showed no loss in capacitance after 10000 cycles. The results demonstrate that anodization of steel is a suitable method to produce high-surface-area electrodes for supercapacitors with excellent cycling lifetime