Effect of Time Depositions on Electrodeposited Cobalt-Iron Nanocoating

2012 ◽  
Vol 576 ◽  
pp. 565-568 ◽  
Author(s):  
Wan Normimi Roslini Abdullah ◽  
Koay Mei Hyie ◽  
Nor Azrina Resali ◽  
Chong Wen Tong

Cobalt-Iron (CoFe) nanocrystalline coatings are successfully prepared in 30, 60 and 90 minutes time depositions using electrodeposition method. The effect of time deposition towards crystallographic structure, elemental composition, surface morphology, microhardness and corrosion behaviour of CoFe coatings were investigated. The CoFe nanocrystalline coatings were deposited on stainless steel substrate at pH 3 environment. The grain sizes of the coatings are in the range of 57.88 to 70.18 nm. The CoFe nanocrystalline coating prepared at 90 minutes deposition achieves the highest microhardness of 290 HV. This coating also exhibits the lowest corrosion rate with 1.086 mpy. It is found that the increment of time deposition improves the microhardness and corrosion behavior of CoFe nanocrystalline coatings.

2012 ◽  
Vol 486 ◽  
pp. 108-113 ◽  
Author(s):  
Koay Mei Hyie ◽  
Nor Azrina Resali ◽  
Wan Normimi Roslini Abdullah

Cobalt and its alloy have been identified as potential candidates for replacing hexavalent Chromium plating in corrosion resistant coating in acidic environment. In this study, the effect of alloys addition towards elemental composition, crystallographic structure characterization, surface morphology, hardness and potentiodynamic polarization of the cobalt alloys coatings is reported. Addition of Nickel (Ni) and Iron (Fe) to the Cobalt (Co) coatings are deposited on stainless steel substrate by electrodeposition method. The deposition is performed at acidic environment of pH 3. The granule sizes of cobalt alloys prepared by electrodepositionmethod are in the range of 34.95 nm72.08 nm. The microhardness of CoNiFe is the highest (267.8 HV) compared to Co and CoFe. CoNiFeperforms the smallest corrosion rate with 1.322 mmpy. It is found thatthe addition of Ni and Fe into pure cobaltimproves the hardness and corrosion behavior.


2013 ◽  
Vol 456 ◽  
pp. 392-398
Author(s):  
Ze Fen Liang ◽  
Min Zheng

In the present paper the influence of the addition of MoSi2particles on the microstructure and pitting corrosion behaviour of laser cladding Co based alloy coatings deposited on 304 stainless steel substrate has been reported. The coating microstructure was investigated by SEM, OM, XRD and EPMA etc.. And the pitting corrosion resistance of coating was evaluated in the 3.5% NaCl solution. The results showed that: (1) The microstructure is fined by increasing MoSi2percentage. And the coating microstructure evolved from dendrites and interdendritic eutectics to various faceted dendrites with the bamboo leaf, flower, or butterfly morphology, when the MoSi2content is from 0~20% to 30~40%; (2) the (Epit-Eprot) of Co based alloy/MoSi2composite coating was lower than that of Co based alloy, and which presented higher self-repairing capability. The pitting potential Epitof Co +(0~20wt.%) MoSi2cladding coatings is higher than that of stainless steel, the pitting corrosion resistance is enhanced; When more MoSi2(30wt.%) was added, the pitting corrosion resistance decreases due to microstructure inhomogeneity and exiting of inclusion.


2013 ◽  
Vol 133 (4) ◽  
pp. 126-127 ◽  
Author(s):  
Shota Hosokawa ◽  
Motoaki Hara ◽  
Hiroyuki Oguchi ◽  
Hiroki Kuwano

2020 ◽  
Vol 32 (4) ◽  
pp. 042015
Author(s):  
Alireza Mostajeran ◽  
Reza Shoja-Razavi ◽  
Morteza Hadi ◽  
Mohammad Erfanmanesh ◽  
Hadi Karimi

2012 ◽  
Vol 490-495 ◽  
pp. 3486-3490
Author(s):  
Qiang Yu ◽  
Zhen Chen ◽  
Zhong Cheng Guo

In order to prepare a new type of anode material, stainless steel was selected as substrate material. The β-PbO2 coating on stainless steel substrate was prepared under the appropriate plating solution, and the PbO2-MnO2 coating was prepared with thermal decomposition. The crystal structure was determined by X-ray diffraction; Surface morphology was test by Scanning Electron Microscopy; the energy spectrum was used to determine element mass-fraction and the ratio of atomic number of the coatings.


Author(s):  
Srikant Tiwari ◽  
Suryanarayan B Mishra

Artificial material such as stainless steel (SS) is widely used for orthopaedic applications owing to its superior properties, ease of fabrication and lower cost. However, in the body environment, stainless steel can leach toxic elements such as nickel and chromium. To prevent this, a hydroxyapatite (HAp) coating having chemical characteristics very similar to the human bone was deposited on a medical-grade UNS S31254 austenitic stainless steel by a Low-velocity oxy-fuel spray gun (LVOF). The coating was characterised by using a field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD) and Fourier transform infrared spectroscope (FTIR). The adhesion strength, microhardness and corrosion behaviour were studied using the Tensometre, Vickers microhardness tester and potentiodynamic polarisation with electrochemical impedance spectroscope. The bacterial adhesion and bioactivity of the coating were also evaluated. The LVOF sprayed HAp coating has shown better corrosion resistance, higher bioactivity and higher hardness than the uncoated steel. The presence of tricalcium phosphate, octa-calcium phosphate (OCP) and tetra-calcium phosphate (TTCP) was found in the coating. LVOF sprayed HAp coating is also found suitable in lowering the bacterial adhesion on the steel substrate.


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