Effects of Current Density on the Microstructure and Properties of Electrodeposited Black Cr-C Nano-Composite Coatings on Steel Substrate

2011 ◽  
Vol 687 ◽  
pp. 641-646 ◽  
Author(s):  
Xue Song Li ◽  
Yue Yang ◽  
You Yang ◽  
Hua Wu

Eelectrodeposited black Cr-C nano-composite coating was prepared on the steel substrate and the effects of current density on the properties of the composite coating were studied in the present paper. The surface morphology and phase composition of the composite coatings were analyzed by means of scanning electronic microscopy (SEM) and X-ray diffractometer (XRD). Microhardness was determined by micrometer and the wear resistance of the coatings was evaluated by CETR using a universal materials tester (UMT). The results showed that formed under the condition of current density of 100A/dm2, temperature of 15°C, and the optimum particle content in electrolyte was 10g/l. The maximum microhardness of black Cr-C nano-composite coating was 10.8 Gpa, simutaneously, the wearing resistance of the coating improved significantly compared to the steel substrate.

Author(s):  
Chandrasekhara Sastry Chebiyyam ◽  
Pradeep N ◽  
Shaik AM ◽  
Hafeezur Rahman A ◽  
Sandeep Patil

Abstract Nano composite coatings on HSLA ASTM A860 alloy, adds to the barrier efficacy by increase in the microhardness, wear and corrosion resistance of the substrate material. Additionally, reduction of delamination of the nano composite coating sample is ascertained. Ball milling is availed to curtail the coating samples (Al2O3/ZrO2) to nano size, for forming a electrodeposited product on the substrate layer. The curtailment in grain size was ascertained to be 17.62% in Ni-Al2O3/ZrO2 nano composite coating. During the deposition process, due to the presence of Al2O3/ZrO2 nano particles an increase in cathode efficiency is ascertained. An XRD analysis of the nano composite coating indicates a curtailment in grain size along with increase in the nucleation sites causing a surge in the growth of nano coating layer. In correlation to uncoated HSLA ASTM A36 alloy sample, a surge in compressive residual stress by 47.14%, reduction of waviness by 32.14% (AFM analysis), upsurge in microhardness by 67.77% is ascertained in Ni-Al2O3/ZrO2 nano composite coating. Furthermore, in nano coated Ni-Al2O3/ZrO2 composite a reduction is observed pertaining to weight loss and friction coefficients by 27.44% and 13% in correlation to plain uncoated alloy respectively. A morphology analysis after nano coating indicates, Ni-Al2O3/ZrO2 particles occupy the areas of micro holes, reducing the wide gaps and crevice points inside the matrix of the substrate, enacting as a physical barrier to upsurge the corrosion resistance by 67.72% in correlation to HSLA ASTM A860 base alloy.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Zhisheng Li ◽  
Zongde Liu ◽  
Yongtian Wang ◽  
Shunv Liu ◽  
Runsen Jiang ◽  
...  

Fe-based amorphous composite coating was deposited on the carbon steel substrate by arc spraying and then remelted by a plasma remelting system, in order to improve the mechanical properties of the coatings. The composition, microstructure, and properties of the composite coating were analyzed by means of the metallographic microscope, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and microhardness tester. The results showed that the amorphous composite coatings had more homogeneous and finer microstructure after the plasma remelting. The coating is metallurgically bonded with the substrate, and the hardness of the Fe-based amorphous composite coating is up to 1220 HV. The internal relationship between microhardness and microstructure has been discussed.


2011 ◽  
Vol 311-313 ◽  
pp. 344-347
Author(s):  
Qian Wang

Compared with ordinary coatings, nano-composite coating usually has a higher hardness and better wear and corrosion resistance. As coating materials, the nano-CeO2/Zn composites were prepared by nano-CeO2 and Zn powder. The microstructure was investigated by XRD and FESEM. The corrosion resistance and hardness of nano-CeO2/Zn composites with different amount of nano-CeO2 were comparatively studied. The results show that the metal corrosion resistance, hardness and density of the composites may be improved significantly by addition of nano-CeO2, and the optimal amount of nano-CeO2 is 1%.


2013 ◽  
Vol 10 (6) ◽  
pp. 515-522
Author(s):  
K. Sharma ◽  
A. Seethagirisha

The mechanical properties like hardness, tensile strength, wear resistance of electro-co-deposited Ni-SiC coatings are dependent on factors like bath temperature, current density, duration of deposition, amount of SiC particles etc. Ni-SiC nano composite coatings were prepared on a mild steel substrate by electro-co-deposition process. In this study, the effect of electrochemical bath parameters such as bath temperature, current density and SiC loading were varied and effect of this variation on the coating thickness and tensile strength of Ni-SiC composite coating was studied. The experimental results showed that, a uniform deposit thickness was obtained for 3 A/dm2 current density, temperature of 55°C and loading of 4 g/l. A peak value of coating thickness was observed at a current density of 4 A/dm2 from the experiment. The experimental results also showed that, the tensile strength of the composite coating containing SiC the is significantly higher than pure Ni coating and the tensile strength increases with an increase in the percentage of SiC particles in Ni-SiC coatings. The tensile strength of the composite coating increased by nearly about 52% with increasing SiC loading and then decreased.


2021 ◽  
Vol 2114 (1) ◽  
pp. 012077
Author(s):  
N Salam ◽  
M A. Jaleel

Abstract In this paper, we succeeded in obtaining a Ni/SiC nano composite coating using conventional electro deposition by adding different amount of SiC nanoparticles to a nickel-watt bath to be co-deposited. The effect of electro deposition conditions was studied by changing the amount of SiC nanoparticles in the nano composite, and the deposition current density which affects on the participation of SiC nanoparticles in the coating. The morphology and mechanical properties of the electrodeposited nano-composite were studied. The wear behavior of the nano-composite coatings was evaluated on a ball-on-disk test. It was found that the increased micro hardness and wear resistance of the nano-composite coatings increased with increasing content of the SiC nano-particulate in bath.


2012 ◽  
Vol 482-484 ◽  
pp. 2371-2375
Author(s):  
Xiao He Wang ◽  
Bin Shi Xu ◽  
Zhen Feng Hu ◽  
Shi Yun Dong

To remanufacture hard chromium-plated workpiece, nano-Al2O3/Ni-Co composite coatings and Ni-Co alloy coatings are developed using electric brush plating technology. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) are used to analyze the surface morphology, phase structure and wear properties of coatings. The surface morphology of nano-composite coating is more compact. The nano-particles are well-distributed in the coating and bounded tightly with the substrate. The hardness of composite coating is HV1027, increased approximately 38% compared with Ni-Co alloy coating, overtaking the hard chrome plating. The results of sliding wear test shows that the nano-composite coating reduces friction coefficient, increases wear resistance significantly and exceeds the chromium plating.


2016 ◽  
Vol 53 (3) ◽  
pp. 144-160
Author(s):  
D. Dietrich ◽  
A. Eilert ◽  
D. Nickel ◽  
T. Lampke

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