scholarly journals Study of the Novel Ni/Co–SiC Coatings Deposited by Pulse Current Electrodeposition. Influence of the Pulse Frequency and the Duty Cycle

Author(s):  
Xinlong Yu ◽  
Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1182
Author(s):  
Hongbin Zhang ◽  
Fafeng Xia ◽  
Jindong Wang ◽  
Fengxia Xu

This paper describes the pulse current electrodeposition (PCE) mediated preparation of Ni-W/TiN nanocomposites. Pulse current electrodeposition (PCE) was used to make Ni-W/TiN nanocomposites. The nanoindentation, wear, and corrosion of deposited Ni-W/TiN nanocomposites were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The influence of pulse frequency (PF) and duty ratio on the shape, structure, phase structure, wear, and corrosion resistance of Ni-W/TiN nanocomposites was studied. When the duty cycle (DC) was 10%, the results demonstrated that a considerable number of fine grains were present on the deposited Ni-W/TiN nanocomposites, forming smooth, uniform, and fine organization. Increasing DC decreased the content of TiN nanoparticles in Ni-W/TiN nanocomposites. The content of TiN nanoparticles reduced from 11.3 wt % to 7.3 wt % by increasing the DC from 10% to 50%. In contrast, as the PF was increased, the TiN content in Ni-W/TiN nanocomposites increased. When the PF was increased from 50 Hz to 150 Hz, the TiN content increased from 6.4 wt % to 9.6 wt %, respectively. Furthermore, with a PF of 150 Hz and a DC of 10%, the produced Ni-W/TiN nanocomposites had an average hardness of 934.3 HV with ~39.8 µm of an average thickness. The weight loss of the Ni-W/TiN nanocomposites was just 17.2 mg at a PF of 150 Hz, demonstrating the excellent wear resistance potential. Meanwhile, the greatest impedance was found in Ni-W/TiN nanocomposites made with a DC of 10% and a PF of 150 Hz, indicating the best corrosion resistance.


2007 ◽  
Vol 364-366 ◽  
pp. 232-236 ◽  
Author(s):  
Shih Tsung Ke ◽  
Jeou Long Lee ◽  
Yih Min Yeh ◽  
Shuo Jen Lee ◽  
Ming Der Ger

In this study, a Ni-P alloy electroforming nanostructure material with low surface roughness and low internal stress was developed by using a pulse current. Square-wave cathodic current modulation was employed to electrodeposit ultrafine-grained Ni-P films from an additivefree Sulfamate nickel bath. The effect of various factors, such as peak current density, duty cycle and pulse frequency on the roughness and internal stress were investigated. Pulse current significantly influences the microstructure of Ni-P alloys. The internal stress and roughness of Ni-P alloys increased as peak current density increased, but the internal stress of Ni-P alloys decreased as duty cycle decreased.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1233
Author(s):  
Yuchao Zhao ◽  
Nan Ye ◽  
Haiou Zhuo ◽  
Chaolong Wei ◽  
Weiwei Zhou ◽  
...  

Tungsten-copper (W–Cu) composites are widely used as electrical contact materials, resistance welding, electrical discharge machining (EDM), and plasma electrode materials due to their excellent arc erosion resistance, fusion welding resistance, high strength, and superior hardness. However, the traditional preparation methods pay little attention to the compactness and microstructural uniformity of W–Cu composites. Herein, W–Cu composite coatings are prepared by pulse electroplating using nano-W powder as raw material and the influence of forward-reverse duty cycle of pulse current on the structure and mechanical properties is systematically investigated. Moreover, the densification mechanism of the W–Cu composite coating is analyzed from the viewpoints of forward-pulse plating and reverse-pulse plating. At the current density (J) of 2 A/dm2, frequency (f) of 1500 Hz, forward duty cycle (df) of 40% and reverse duty cycle (dr) of 10%, the W–Cu composite coating rendered a uniform microstructure and compact structure, resulting in a hardness of 127 HV and electrical conductivity of 53.7 MS/m.


2016 ◽  
Vol 24 (05) ◽  
pp. 1750066 ◽  
Author(s):  
HAMED RAHMANI ◽  
MAHMOOD ALIOFKHAZRAEI ◽  
ABDOSSALAM KARIMZADEH

Nanocomposite Ni–Zn coatings containing 80 wt.% Al2O3, 5 wt.% Y2O3 and 15 wt.% graphene were fabricated by pulsed electrodeposition method in nickel–zinc sulphate-based electrolyte and effects of pulse current parameters on nickel and other element contents, microstructure, resistance to corrosion and tribological properties of the coatings were investigated. The pulsed current with duty cycle from 10% to 50% was applied to different samples and frequency changed gradually from 500 to 4000[Formula: see text]Hz in five steps during coating process. Increasing the duty cycle led to decrease of absorbed nanoparticles in the surface of the coatings from 4.4 vol% to 3.58 vol% The sample coated with 10% duty cycle had utmost alumina content in the coating surface, 3.5 vol% in first layer up to 4.4 vol% in fifth layer. The sample coated with 30% duty cycle had higher corrosion resistance with passive current density of 2.5[Formula: see text]mA/cm2. Furthermore, the results showed that by increasing the duty cycle, wear rate had been increased up to 1.3[Formula: see text][Formula: see text][Formula: see text]10[Formula: see text][Formula: see text]mm2/N[Formula: see text]m.


2006 ◽  
Vol 2006 (3) ◽  
pp. 266-270 ◽  
Author(s):  
A. N. Gulivets ◽  
V. A. Zabludovskii ◽  
A. S. Baskevich

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