PREPARATION AND INVESTIGATION OF ELECTRODEPOSITED Ni–NANO-Cr2O3 COMPOSITE COATINGS

2016 ◽  
Vol 23 (02) ◽  
pp. 1550111 ◽  
Author(s):  
JIBO JIANG ◽  
CHENQI FENG ◽  
WEI QIAN ◽  
LIBIN YU ◽  
FENGYING YE ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Charge Transfer Resistance ◽  
X Ray Diffraction ◽  
Transfer Resistance ◽  
X Ray ◽  
Potentiodynamic Polarization Curves ◽  
Nucleation Sites ◽  
Passive Transition ◽  
Steel Surfaces

The electrodeposition of Ni–nano-Cr2O3 composite coatings was studied in electrolyte containing different contents of Cr2O3 nanoparticles (Cr2O3 NPs) on mild steel surfaces. Some techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness, the potentiodynamic polarization curves (Tafel) and electrochemical impedance spectroscopy (EIS) were used to compare pure Ni coatings and Ni–nano-Cr2O3 composite coatings. The results show that the incorporation of Cr2O3 NPs resulted in an increase of hardness and corrosion resistance, and the maximum microhardness of Ni-nano-Cr2O3 composite coatings reaches about 495 HV. The coatings exhibit an active-passive transition and relatively large impedance values. Moreover, the effect of Cr2O3 NPs on Ni electrocrystallization is also investigated by cyclic voltammetry (CV) and EIS spectroscopy, which demonstrates that the nature of Ni-based composite coatings changes attributes to Cr2O3 NPs by offering more nucleation sites and less charge transfer resistance.

Effect of Zirconium Oxide Reinforcement on Microstructural, Electrochemical and Mechanical Properties of TiNi Alloy Produced Via Powder Metallurgy Route

2021 ◽  
pp. 1-22
Author(s):  
Syed Abbas Raza ◽  
Muhammad Imran Khan ◽  
Muhammad Ramzan Abdul karim ◽  
Rashid Ali ◽  
Muhammad Umair Naseer ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Passive Layer ◽  
Charge Transfer Resistance ◽  
Tini Alloy ◽  
X Ray Diffraction ◽  
Zro2 Content ◽  
Transfer Resistance ◽  
X Ray ◽  
Conventional Sintering ◽  
Layer Resistance

Abstract Equiatomic TiNi alloy composites, reinforced with 0, 5, 10 and 15 vol. % ZrO2, were synthesized using conventional sintering approach. Equiatomic TiNi pre-alloyed powder and ZrO2 powder were mixed in planetary ball mill for 6 hours followed by cold compaction and pressure-less sintering, respectively. The sintered density was found to vary inversely with the addition of ZrO2 content. The X-Ray diffraction spectra have shown the formation of multiple-phases which were resulted from the decomposition of the B19'and B2 phases of the equiatomic TiNi alloy due to the addition of ZrO2 and higher diffusion rate of Ni than that of Ti in the alloy composite. An increase in hardness was noted due to the addition of ZrO2, measured by micro and nanoindentation techniques. Potentiodynamic polarization scan revealed a 10% decrease in the corrosion rate of the composite containing 10 vol. % ZrO2. Electrochemical impedance spectroscopy results indicated an increase in passive layer resistance (Rcoat) due to the increase in charge transfer resistance (Rct) caused by the reduced leaching of ions from the surface.

scholarly journals Influence of HAP on the Morpho-Structural Properties and Corrosion Resistance of ZrO2-Based Composites for Biomedical Applications

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 202
Author(s):  
Réka Barabás ◽  
Carmen Ioana Fort ◽  
Graziella Liana Turdean ◽  
Liliana Bizo
Keyword(s):  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Synergetic Effect ◽  
Composite Layer ◽  
Charge Transfer Resistance ◽  
Processing Route ◽  
Dental Alloys ◽  
Metallic Electrode ◽  
Transfer Resistance ◽  
X Ray

In the present work, ZrO2-based composites were prepared by adding different amounts of antibacterial magnesium oxide and bioactive and biocompatible hydroxyapatite (HAP) to the inert zirconia. The composites were synthesized by the conventional ceramic processing route and morpho-structurally analyzed by X-ray powder diffraction (XRPD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Two metallic dental alloys (i.e., Ni–Cr and Co–Cr) coated with a chitosan (Chit) membrane containing the prepared composites were exposed to aerated artificial saliva solutions of different pHs (i.e., 4.3, 5, 6) and the corrosion resistances were investigated by electrochemical impedance spectroscopy technique. The obtained results using the two investigated metallic dental alloys shown quasi-similar anticorrosive properties, having quasi-similar charge transfer resistance, when coated with different ZrO2-based composites. This behavior could be explained by the synergetic effect between the diffusion process through the Chit-composite layer and the roughness of the metallic electrode surface.

scholarly journals Electrodeposition Kinetics of Ni/Nano-Y2O3 Composite Coatings

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 669
Author(s):  
Xinyu Zhou ◽  
Yiyong Wang ◽  
Xianglin Liu ◽  
Zhipeng Liang ◽  
Hui Jin
Keyword(s):  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Composite Films ◽  
Linear Sweep Voltammetry ◽  
Electrochemical Measurement ◽  
Charge Transfer Resistance ◽  
Solid Particles ◽  
Kinetics Parameters ◽  
Transfer Resistance ◽  
Composite Deposition

Ni/nano-Y2O3 composite films were successfully prepared by electrochemical deposition using an acid sulfamate bath. The influence of solid particles added to electrolyte on electrodeposition was investigated by electrochemical measurement methods. The linear sweep voltammetry test showed that the composite deposition took place at a greater potential than that of nickel, and the presence of nano-Y2O3 decreased cathodic polarization. Chronoamperometry studies indicated that the nucleation model of both deposits similarly approached the theoretical instantaneous nucleation mode based on the Scharifker–Hills model. The Y2O3 particles adsorbed on the cathodic surface were shown to facilitate the nucleation/growth of the nickel matrix which is consistent with the deposition kinetics parameters calculated by non-linear fitting experimental curves. The results of electrochemical impedance spectroscopy showed that the presence of Y2O3 particles in a bath is beneficial for the decrease in charge transfer resistance in the deposition. The atomic force microscopy observations of both deposits obtained in the initial electrodeposition stage confirmed that the Ni-Y2O3 composite had a higher grain number and finer mean grain size.

scholarly journals Effect of Graphene Oxide Concentration in Electrolyte on Corrosion Behavior of Electrodeposited Zn–Electrochemical Reduction Graphene Composite Coatings

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 758 ◽  
Author(s):  
Yang ◽  
Zhang ◽  
Wang ◽  
Wang ◽  
Chen ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Laser Raman Spectroscopy ◽  
304 Stainless Steel ◽  
Sulfate Electrolyte ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tafel Polarization ◽  
Laser Raman

Pure Zn and Zn–ERGO composite coatings were prepared by direct current electrodeposition on 304 stainless steel. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS), and laser Raman spectroscopy (Raman). Results obtained have shown that the concentration of GO sheets in zinc sulfate electrolyte has an important effect on the preferred crystal orientation and the surface morphology of Zn–ERGO composite coatings. A study of the corrosion behavior of the coatings by Tafel polarization and electrochemical impedance spectroscopic (EIS) methods leads to the conclusion that the Zn-1.0 g/L ERGO composite coating possesses the best corrosion resistance compared to the pure Zn coating and other composite coatings in this study.

MICROSTRUCTURE AND WEAR RESISTANCE OF IN-SITU SYNTHESIZED TiB2–TiC/Fe COMPOSITE COATING BY LASER CLADDING

2020 ◽  
pp. 2050046
Author(s):  
TIANWEI YANG ◽  
ZHAOHUI WANG ◽  
SHIHAI TAN ◽  
FU GUO
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Composite Coatings ◽  
X Ray Diffraction ◽  
Mixed Powder ◽  
X Ray ◽  
Material Surfaces ◽  
Metallurgical Bonding ◽  
Steel Surfaces

To increase the strength and wear resistance of material surfaces, various combinations of B4C and 80TiFe powder were mixed into a Fe60 self-fluxing alloy powder; the composite coatings reinforced by TiB2–TiC were successfully prepared on Q235 steel surfaces by laser cladding. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to study the microstructure and chemical and phase composition. Microhardness and wear testers were used to investigate the mechanical properties. The results show that the interfaces of composite coatings and substrate materials are excellent for metallurgical bonding. The block-like TiB2 particles and flower-like TiC particles are uniformly distributed in the cladding coating. When the mass fraction of the mixed powder is 30%, the average microhardness of the coating is approximately 1100 HV[Formula: see text], which is 50% higher than that without the mixed powder, and demonstrates the best wear with a performance twice as better as that of the substrate.

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.

scholarly journals From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room- and Elevated- Temperature Li-ion Storage

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jialiang Tang ◽  
Vinodkumar Etacheri ◽  
Vilas G. Pol
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
High Rate ◽  
Energy Storage Devices ◽  
Lithium Storage ◽  
Transfer Resistance ◽  
Carbonaceous Particles ◽  
X Ray

Abstract The conversion of allergic pollen grains into carbon microstructures was carried out through a facile, one-step, solid-state pyrolysis process in an inert atmosphere. The as-prepared carbonaceous particles were further air activated at 300 °C and then evaluated as lithium ion battery anodes at room (25 °C) and elevated (50 °C) temperatures. The distinct morphologies of bee pollens and cattail pollens are resembled on the final architecture of produced carbons. Scanning Electron Microscopy images shows that activated bee pollen carbon (ABP) is comprised of spiky, brain-like and tiny spheres; while activated cattail pollen carbon (ACP) resembles deflated spheres. Structural analysis through X-ray diffraction and Raman spectroscopy confirmed their amorphous nature. X-ray photoelectron spectroscopy analysis of ABP and ACP confirmed that both samples contain high levels of oxygen and small amount of nitrogen contents. At C/10 rate, ACP electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities. Through electrochemical impedance spectroscopy studies, improved performance of ACP is attributed to its lower charge transfer resistance than ABP. Current studies demonstrate that morphologically distinct renewable pollens could produce carbon architectures for anode applications in energy storage devices.

scholarly journals Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4631 ◽  
Author(s):  
Juan Aliaga ◽  
Pablo Vera ◽  
Juan Araya ◽  
Luis Ballesteros ◽  
Julio Urzúa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Charge Transfer Resistance ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Transfer Resistance ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

In this research, we report a simple hydrothermal synthesis to prepare rhenium (Re)- doped MoS2 flower-like microspheres and the tuning of their structural, electronic, and electrocatalytic properties by modulating the insertion of Re. The obtained compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Structural, morphological, and chemical analyses confirmed the synthesis of poorly crystalline Re-doped MoS2 flower-like microspheres composed of few stacked layers. They exhibit enhanced hydrogen evolution reaction (HER) performance with low overpotential of 210 mV at current density of 10 mA/cm2, with a small Tafel slope of 78 mV/dec. The enhanced catalytic HER performance can be ascribed to activation of MoS2 basal planes and by reduction in charge transfer resistance during HER upon doping.

PREPARATION AND CHARACTERIZATION OF A POLY(PYRROLYL METHANE)/MULTIWALLED CARBON NANOTUBES COMPOSITES

NANO ◽  
2013 ◽  
Vol 08 (06) ◽  
pp. 1350063
Author(s):  
JINXIAN LIN ◽  
PAN WANG ◽  
YUYING ZHENG
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Electrode System ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Transfer Resistance ◽  
Transmission Electron

A poly(pyrrolyl methane) (Poly[pyrrole-2, 5-diyl(4-methoxybenzylidane)], PPDMOBA)/multiwalled carbon nanotubes (MWNTs) composites are fabricated by in situ chemical polycondensation of pyrrole and 4-methoxybenzaldehyde on MWNTs. The structure, morphology, thermal stability and electrical property of the resulting composites are investigated via fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and a four-probe method. The electrochemical performance of the composites is determined in a three-electrode system using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. FTIR, FESEM and TEM confirm that the composites have been successfully prepared, and PPDMOBA is uniformly dispersed in MWNTs. Electrical conductivity of PPDMOBA/MWNTs composites is 1.39 S cm-1, which is significantly larger than that of pristine PPDMOBA. The specific capacitance and charge transfer resistance of the composites is 56 F g-1 (1 mA cm-2) and 0.3Ω, respectively.

Preparation and electrochemical characterization of PANI/MnCo2O4 nanocomposite as supercapacitor electrode material

2018 ◽  
Vol 96 (5) ◽  
pp. 477-483 ◽  
Author(s):  
Saeid Panahi ◽  
Moosa Es’haghi
Keyword(s):  
Specific Capacitance ◽  
Surface Characterization ◽  
Electrochemical Impedance ◽  
Rate Capability ◽  
Cycling Performance ◽  
Charge Transfer Resistance ◽  
X Ray Diffraction ◽  
Supercapacitor Electrode ◽  
Transfer Resistance

In this work, PANI/MnCo2O4 nanocomposite was prepared via in-situ chemical polymerization method. Materials synthesized were characterized by FTIR spectroscopy, X-ray diffraction, and scanning electron spectroscopy. In addition, surface characterization of samples such as specific surface area, pore volume, and pore size distribution was studied. Supercapacitor capability of materials was investigated in 1 mol L–1 Na2SO4 solution using cyclic voltammetry in different potential scan rates and electrochemical impedance spectroscopy (EIS). The specific capacitance of materials was calculated, and it was observed that the specific capacitance of PANI/MnCo2O4 nanocomposite was 185 F g−1, much larger than PANI. Moreover, the prepared nanocomposite exhibited better rate capability in scan rate of 100 mV s−1 with respect to PANI. The EIS experiments revealed that the nanocomposite has lower charge transfer resistance compared with pure PANI. Subsequently, it was shown that the nanocomposite cycling performance was superior to the PANI cycling performance.

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