Characterization of Cr-α-Al2O3 Composite Coatings Electrodeposited from Cr(Ⅲ) Plating Bath

2011 ◽  
Vol 121-126 ◽  
pp. 60-64
Author(s):  
Xin Sun ◽  
Xiang Zhu He ◽  
Yong Xiu Wang ◽  
Zhi Hong Fu
Keyword(s):  
Corrosion Resistance ◽  
Direct Current ◽  
Composite Coatings ◽  
Microhardness Measurement ◽  
Plating Bath ◽  
Fine Grained ◽  
Measurement Results ◽  
Naoh Solution ◽  
Fine Grained Structure

Cr-α-Al2O3composite coatings were prepared by direct current deposition experiments from Cr(Ⅲ) plating bath and the thickness of composite coatings could be up to 14 μm. The obtained Cr-α-Al2O3coatings and Cr coatings were characterized by means of EDS, SEM and microhardness measurement. Results revealed that Cr-α-Al2O3coatings exhibit fine-grained structure with uniform surface and the highest microhardness values(692 HV) when the α-Al2O3content of coatings was 15g/L, although some pores and defects are still present in the coatings. Analysis of Tafel curves indicated that the presence of α-Al2O3in the Cr coatings show better features in the corrosion resistance both in H2SO4and NaOH solution than those prepared from the bath without α-Al2O3.

Effect of Complex Agents on the Performance of Electrodeposited Ni-Graphite Composites

2011 ◽  
Vol 239-242 ◽  
pp. 2888-2894 ◽  
Author(s):  
Xiang Zhu He ◽  
Xiao Wei Zhang ◽  
Xin Li Zhou ◽  
Yong Xiu Wang
Keyword(s):  
Corrosion Resistance ◽  
Excellent Performance ◽  
Fine Grained ◽  
High Microhardness ◽  
Naoh Solution ◽  
Fine Grained Structure ◽  
Graphite Composites ◽  
Graphite Coatings ◽  
Better Than ◽  
Sulfamate Bath

Ni-graphite composites were prepared using co-electrodeposited technique in sulfamate bath. To obtain an optimum combination of nickel and graphite in the composites with excellent performance such as wear resistance, corrosion resistance and microhardness and so on, effects of complex agents on the performances of composites were investigated in this work. The obtained Ni-graphite coatings were characterized by means of SEM, EDS and the microhardness measurement, it was revealed that Ni-graphite coating exhibit fine-grained structure with uniform surface and high microhardness values, although some pores and defects were still present in the coating. In addition, the co-electrodeposited Ni-12.16vol% graphite coatings showed considerably better performance, analysis of Tafel curves demonstrated that corrosion resistance of the coating prepared from bath containing complex agents were better than those prepared from bath without complex agents in the NaCl and HCl solution, but worse in the NaOH solution.

Characterization of Cr-Ni-ZrO2 Composite Coatings Electrodeposited from Cr(III) Plating Bath

2011 ◽  
Vol 239-242 ◽  
pp. 2733-2737 ◽  
Author(s):  
Xiang Zhu He ◽  
Xin Li Zhou ◽  
Xiao Wei Zhang ◽  
Xin Sun
Keyword(s):  
Corrosion Resistance ◽  
Composite Coatings ◽  
Electrochemical Corrosion ◽  
Plating Bath ◽  
Corrosion Tests ◽  
Ni Alloy ◽  
Mass Proportion ◽  
Hardness Values ◽  
Composite Electrodeposition

New Cr-Ni-ZrO2 composite coatings are prepared by composite electrodeposition. The morphology, composition and corrosion resistance of as-deposited Cr-Ni-ZrO2 coatings are systematically characterized by means of SEM, EDS. The hardness of as deposited and annealed Cr-Ni-ZrO2 coatings are also discussed. The electrochemical corrosion tests are conducted by means of Tafel plots. Results of SEM and EDS show that Cr-Ni-ZrO2 composite coatings with homogeneous and crack-free morphology have been prepared successfully; the mass proportion of Zr in the as-deposited coatings is up to 7.85%. The hardness values of Cr-Ni-ZrO2 coatings are higher than that of Cr-Ni alloy coatings. Furthermore, the hardness values increase and then decrease with the temperature increasing when annealed. Analysis of Tafel plots demonstrates that Cr-Ni-ZrO2 coatings have much better corrosion resistance than that of Cr-Ni coatings.

scholarly journals Microstructural and Mechanical Characterization of Multilayered Iron Electrodeposits

2011 ◽  
Vol 409 ◽  
pp. 474-479 ◽  
Author(s):  
C. Chan ◽  
J.L. McCrea ◽  
G. Palumbo ◽  
Uwe Erb
Keyword(s):  
Mechanical Properties ◽  
Columnar Structure ◽  
Multilayered Structure ◽  
Structure Design ◽  
Coarse Grained ◽  
Fine Grained ◽  
Microstructure And Mechanical Properties ◽  
Fine Grained Structure ◽  
Iron Coatings

Monolithic and multilayered iron electrodeposits were successfully synthesized by the pulse plating electrodeposition method. Electron microscopy and Vickers microhardness measurements were used to investigate the microstructure and mechanical properties of the iron electrodeposits produced. Two types of monolithic iron coatings were produced, one with a coarse grained, columnar structure and the other with an ultra-fine grained structure. Hall-Petch type grain size strengthening was observed in these monolithic coatings. Multilayered iron coatings composed of alternating layers of coarse grained and fine grained structures were also produced. The hardness value of the multilayered coatings falls between the hardness values for the two types of monolithic coatings produced. This study has demonstrated the possibility of applying a multilayered structure design to tailor the microstructure and mechanical properties of electrodeposited iron coatings.

Electrodeposition and Hardness and Corrosion Resistance Propertie of Ni/Nano-B4C Composite Coatings

2011 ◽  
Vol 399-401 ◽  
pp. 2055-2060
Author(s):  
Ji Bo Jiang ◽  
Wei Dong Liu ◽  
Lei Zhang ◽  
Qing Dong Zhong ◽  
Yi Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Pure Nickel ◽  
Plating Bath ◽  
Tafel Polarization ◽  
Nickel Coatings ◽  
Eis Measurements ◽  
Steel Substrates

Ni–B4C composite coatings on carbon steel substrates with various contents of B4C nano-particulates were prepared by electrodeposition in Ni plating bath containing B4C nano-particulates. Microhardness, Scanning Electron Microscopy (SEM), Tafel polarization and Electrochemical Impedance Spectroscopy (EIS) measurements were used to compare pure nickel coatings and Ni–B4C composite coatings. Pure Ni coating microhardness is lower than that of Ni–B4C coatings and the microhardness of the composite coatings increases with the increase of the content of B4C nano-particulates. The effects of various contents of B4C nano-particulates on the corrosion resistance were investigated and it was found that the best anti–corrosion property of Ni–B4C composite coatings is at 6 g/L B4C in the bath formulation.

T-RMSD: A Fine-grained, Structure-based Classification Method and its Application to the Functional Characterization of TNF Receptors

2010 ◽  
Vol 400 (3) ◽  
pp. 605-617 ◽  
Author(s):  
Cedrik Magis ◽  
François Stricher ◽  
Almer M. van der Sloot ◽  
Luis Serrano ◽  
Cedric Notredame
Keyword(s):  
Functional Characterization ◽  
Classification Method ◽  
Tnf Receptors ◽  
Fine Grained ◽  
Fine Grained Structure

Preparation and characterization of superhydrophobic composite coatings on a magnesium–lithium alloy

RSC Advances ◽  
2016 ◽  
Vol 6 (93) ◽  
pp. 90587-90596 ◽  
Author(s):  
Zhijun Li ◽  
Yi Yuan
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
Composite Coatings ◽  
Alloy Surface ◽  
Water Repellent ◽  
Lithium Alloy

We report a superhydrophobic organophosphonate composite coating on a magnesium–lithium alloy surface, which exhibits excellent water-repellent and corrosion resistance properties.

Structural Characterization of FeAl28Cr5 Alloy Deformed in the Hot Torsion Process

2016 ◽  
Vol 246 ◽  
pp. 43-46 ◽  
Author(s):  
Iwona Bednarczyk ◽  
Magdalena Jabłońska
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Structural Changes ◽  
Al Alloys ◽  
Dynamic Processes ◽  
Fine Grained ◽  
Average Grain Size ◽  
Fine Grained Structure ◽  
Hot Torsion

Current research in the field of iron aluminides are directed towards to understand the structural phenomena occurring during plastic deformation of these alloys. The obtained results of the study and collected informations will be used to determine the description of the structural changes taking place during hot deformation of Fe ̶Al alloys. The article presents the results of the study of the alloy FeAl28Cr5 deformed by hot torsion in temperature range of 800÷1100°C and a strain rate of 0.1 s-1. The analysis of the structure of the alloy FeAl28Cr5 allowed to reveal changes caused by dynamic processes of deformation. The results of torsion tests show the possibility to obtain a fine-grained structure with of parameters of the processes (T=1000°C, 1100°C) and strain of ε=40. After deformation at strain of (ε=40) the structure consists of fine grains with a misorientation angle higher than 15°, and the average grain size diameter D=28.5 micrometers. Deformation at a temperature of T=1000°C and 1100°C is accompanied by superplastic flow effect.

Influences of Pulse Current Density on the Characteristics of Ni-W-P-CeO2-SiO2 Composite Coatings

2011 ◽  
Vol 418-420 ◽  
pp. 856-860 ◽  
Author(s):  
Rui Dong Xu ◽  
Da Cheng Zhai ◽  
Shuang Li Hu
Keyword(s):  
Chemical Composition ◽  
Current Density ◽  
Pulse Current ◽  
Composite Coatings ◽  
Average Current Density ◽  
Fine Grained ◽  
Fine Grained Structure ◽  
Average Current ◽  
S Deposition ◽  
Microhardness Tester

Square-wave double pulse current was used to electrodeposit Ni-W-P-CeO2-SiO2composite coatings in fine-grained structure on the surface of carbon steel, influences of forward pulse average current density, +Jm, in the range of 5~25A/dm2on characteristics of the composite coatings were researched, and the chemical compositionSubscript texts, deposition rate, microhardness and microstructures were evaluated by EDX, SEM and Microhardness tester. The results show that the uniform composite coatings can be obtained at +Jmof 20A/dm2, which possess higher microhardness of 735Hv. The grains sizes of the composite coatings decrease when +Jmis increased from 5A/dm2to 20A/dm2, while the reappearance of large grains structure at 25A/dm2.

Electroplating and characterization of Cr–Al2O3 nanocomposite film from a trivalent chromium bath

2014 ◽  
Vol 61 (4) ◽  
pp. 205-214 ◽  
Author(s):  
Mohsen Salehi Doolabi ◽  
Sayed Khatiboleslam Sadrnezhaad ◽  
Davood Salehi Doolabi
Keyword(s):  
Particle Size ◽  
Corrosion Resistance ◽  
Current Efficiency ◽  
Current Density ◽  
Composite Coatings ◽  
Content Type ◽  
Nanoparticle Agglomeration ◽  
Cathode Copper ◽  
Maximum Current

Purpose – The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath. Design/methodology/approach – Pure Cr and nanocomposite Cr–Al2O3 coatings were electrodeposited from Cr (III) bath onto cathode copper substrates by conventional method. Dependence of current efficiency to current density, Al2O3 content and particle size were investigated. Findings – Current efficiency increased with Al2O3 amount and decreased with Al2O3 particle size. Maximum current efficiency was achieved at 25 A/dm2 for pure Cr and 30 A/dm2 for composite coatings. Al2O3 bath content, current density and stirring rate increased the coating Al2O3 weight per cent significantly. Addition of Al3+ bath composition inhibited nanoparticle agglomeration, increasing film homogeneity. Cr–Al2O3 nanocomposites showed higher microhardness and better corrosion resistance than pure Cr layer. Originality/value – Cr (III) is not as toxic and as carcinogenic as Cr (VI) which is widely used for Cr electroplating these days. Low current efficiency and poor product quality are, however, major drawbacks of the former. This paper describes significant improvements obtainable by addition of Al2O3 nanoparticles to the Cr (III) bath for increasing the microhardness, the corrosion resistance and the current efficiency of the deposition.

Process and Properties of Pulse Electrodeposited RE-Ni-W-P-SiC Composite Coatings

2008 ◽  
Vol 41-42 ◽  
pp. 385-388
Author(s):  
Xiao Yun Zhu ◽  
Zhong Cheng Guo
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Direct Current ◽  
Pulse Current ◽  
Composite Coatings ◽  
Pulse Frequency ◽  
Duty Ratio ◽  
Properties Of Coatings ◽  
Better Than

Process and properties of pulse electrodeposited RE-Ni-W-P-SiC composite coatings were studied. The results show that the deposited rate by pulse current is larger than that by direct current; the deposited coatings by pulse current are better than that by direct current in corrosion resistance and microhardness. And the corrosion resistance of the coatings with pulse current is better than that of stainless steel (1Cr18Ni9Ti). The duty ratio and the pulse frequency in the process of electrodeposition have a large influence on the deposition rate, the composition and the properties of coatings. SEM measurement shows that the crystals with pulse current are smaller and the surface is smoother than that by direct current. It is beneficial to make crystalline grain finer by mixing rare earth.

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