scholarly journals Electrophoretic Deposition of Hydroxyapatite–Chitosan–Titania on Stainless Steel 316 L

Surfaces ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 458-467 ◽  
Author(s):  
Leila Sorkhi ◽  
Morteza Farrokhi-Rad ◽  
Taghi Shahrabi

In this research, hydroxyapatite (HA)–chitosan–titania nanocomposite coatings were formed on 316 L stainless steel using electrophoretic deposition (EPD) from alcoholic (methanol and ethanol) suspensions containing 0.5 g/L chitosan and 2 and 5 g/L HA and 2 and 5 g/L Titania. The effect of different parameters on the deposition rate, morphology, and corrosion resistance of the coatings in simulated body fluid (SBF) at 37 °C has been studied. The coatings’ properties were investigated using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Based on the results of this work, it was found that the deposition rate in ethanolic suspensions is lower than methanolic ones. Moreover, the coating surface was smoother when the ethanol was used as a solvent in suspensions in comparison to the ones where methanol was the solvent. The coating deposited from a suspension containing 0.5 g/L chitosan, 2 g/L HA, and 5 g/L titania with ethanol as solvent had the highest corrosion resistance in SBF at 37 °C.

2020 ◽  
Vol 840 ◽  
pp. 336-344
Author(s):  
Martinus Kriswanto ◽  
Muhammad Khairurrijal ◽  
Dave Leonard Junior Wajong ◽  
Tofan Maliki Kadarismanto ◽  
Yusril Yusuf

Hydroxyapatite (HAp) made of capiz shell has been successfully coated onto stainless steel 316L substrate using electrophoretic deposition (EPD) method. In this study, three variations were applied, they were the voltages of 25 V and 50 V, the withdrawal speeds of 0.1 mm/s, 0.5 mm/s, and 1 mm/s, and the sintering temperatures of 750, 850, and 950 °C. These variations were applied to determine the differences in morphology and crystal structure of the layers so that the most suitable result was obtained as a candidate for the bone implant. Characterization was done by Scanning Electron Microscope and X-Ray Diffractometer. The EPD process and the application of sintering temperature eliminated the phase of B type apatite carbonate which made the purity of the HAp layer higher. The SEM results show that the layer was more homogeneous and free of cracking at a voltage of 50 V and the withdrawal speed of 0.1 mm/s. The layer density was higher as the voltage and sintering temperature increased. Higher sintering temperature also made the layer more homogeneous, but at 950 °C, stainless steel 316L substrate underwent a phase transformation which caused the decreasing of the purity of the HAp layer. The best results were obtained by applying a50 V voltage, a withdrawal speed of 0.1 mm/s, and a sintering temperature of 850 °C.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 543
Author(s):  
Ketan Kumar Sandhi ◽  
Jerzy Szpunar

Nickel superalloy Hastelloy-N, alloy X-750, stainless steel 316 (SS316), and stainless steel 304 (SS304) are among the alloys used in the construction of molten salt reactor (MSR). These alloys were analyzed for their corrosion resistance behavior in molten fluoride salt, a coolant used in MSR reactors with 46.5% LiF+ 11.5% NaF+ 42% KF. The corrosion tests were run at 700 °C for 100 h under the Ar cover gas. After corrosion, significant weight loss was observed in the alloy X750. Weight loss registered in SS316 and SS304 was also high. However, Hastelloy-N gained weight after exposure to molten salt corrosion. This could be attributed to electrochemical plating of corrosion products from other alloys on Hastelloy-N surface. SEM–energy-dispersive X-ray spectroscopy (EDXS) scans of cross-section of alloys revealed maximum corrosion damage to the depth of 250 µm in X750, in contrast to only 20 µm on Hastelloy-N. XPS wide survey scans revealed the presence of Fe, Cr, and Ni elements on the surface of all corroded alloys. In addition, Cr clusters were formed at the triple junctions of grains, as confirmed by SEM–EBSD (Electron Back Scattered Diffraction) analysis. The order of corrosion resistance in FLiNaK environment was X750 < SS316 < SS304 < Hastelloy-N.


2012 ◽  
Vol 4 (10) ◽  
pp. 5134-5141 ◽  
Author(s):  
Srinivasan Nagarajan ◽  
Marimuthu Mohana ◽  
Pitchaimuthu Sudhagar ◽  
Vedarajan Raman ◽  
Toshiyasu Nishimura ◽  
...  

2019 ◽  
Vol 38 (2019) ◽  
pp. 792-805 ◽  
Author(s):  
S. Ramakrishna Kandala ◽  
Kantesh Balani ◽  
Anish Upadhyaya

AbstractThe present study compares the mechanical properties and electrochemical behaviour of austenitic (AISI 316 L) stainless steel compacted at different pressures (200, 400 and 600 MPa), which are conventionally sintered at supersolidus temperature of 1,400°C. As expected, increase in compaction pressure (from 200 MPa) to 600 MPa has shown decreased shrinkage (from 7.3% to 4.2% radial and 5.5% to 3.4% axial, respectively) and increased densification (up to ~92%). Their electrochemical behaviour was investigated in 0.1 N H2SO4 solution by potentiodynamic polarization and electrochemical impedance spectroscopy. The mechanical properties (such as yield-, tensile- and transverse rupture strength) and electrochemical behaviour with pressure have been correlated with densification response and microstructure (pore type, volume and morphology). Highest densification (~92% theoretical) achieved at 600 MPa (compaction pressure) and 1,400°C (sintering temperature) resulted in excellent combination of tensile strength and ductility (456 ± 40 MPa and 25 ± 1.1% respectively), while showing lowest corrosion rate (0.1 mmpy or 4.7 mpy) due to the presence of isolated porosity in the sintered samples.


2012 ◽  
Vol 507 ◽  
pp. 127-133 ◽  
Author(s):  
Sigrid Seuss ◽  
Tayyab Subhani ◽  
Min Yi Kang ◽  
Kenji Okudaira ◽  
Isaac E. Aguilar Ventura ◽  
...  

Electrophoretic deposition (EPD) has been successfully used to deposit composite coatings composed of polyetheretherketone (PEEK) and titanium dioxide (TiO2) nanoparticles on 316L stainless steel substrates. The suspensions of TiO2 nanoparticles and PEEK microparticles for EPD were prepared in ethanol. PEEK-TiO2 composite coatings were optimized using suspensions containing 6wt% PEEK-TiO2 in ethanol with a 3:1 ratio of PEEK to TiO2 in weight and by applying a potential difference of 30 V for 1 minute. A heat-treatment process of the optimized PEEK-TiO2 composite coatings was performed at 335°C for 30 minutes with a heating rate of 10°Cminto densify the deposits. The EPD coatings were microstructurally evaluated by scanning electron microscopy (SEM). It was demonstrated that EPD is a convenient and rapid method to fabricate PEEK/TiO2 coatings on stainless steel which are interesting for biomedical applications.


2010 ◽  
Vol 660-661 ◽  
pp. 454-459 ◽  
Author(s):  
Maurício David Martins das Neves ◽  
Luzinete Pereira Barbosa ◽  
Luís Carlos Elias da Silva ◽  
Olandir Vercino Correa ◽  
Isolda Costa

Stainless steel (SS) powders are used in the preparation of sintered SS products. One of the applications of sintered SS products is as filters in the petrochemical and food processing industries. In these industries, the SS filters are subject to severe conditions associated with the removal of solid particles from the fluid. Hence, SS filters should have adequate mechanical strength and high corrosion resistance. Welding can be used to manufacture SS filters. In this study, sintered AISI 316L specimens were welded using the TIG (Tungsten Inert Gas) process. The weld joints were examined by optical microscopy and by scanning electron microscopy. Electrochemical polarization measurements were carried out to evaluate the influence of welding on the corrosion resistance of sintered filters.


2007 ◽  
Vol 14 (01) ◽  
pp. 71-77 ◽  
Author(s):  
H. LIANG ◽  
Y. HUANG ◽  
F. HE ◽  
H. F. DING ◽  
Y. Z. WAN

Modification of bioceramics by ion implantation of magnesium ( Mg ) is of interest as Mg is the fourth abundant cation in the human body. In this work, magnesium was ion-implanted into a ZrO 2 based bioceramic stabilized with Y 2 O 3 and Al 2 O 3. Both Mg -implanted and unimplanted samples were soaked in a simulated body fluid (SBF) for a period of time. The deposits on the surface of various samples were characterized with scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). We find that the Mg -implanted ZrO 2 shows better bioactivity than the plain bioceramic. These results indicate that Mg -implantation can improve the bioactivity of the ZrO 2 based bioceramic. Mechanisms governing the improvement are discussed in this paper.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guanghui Yi ◽  
Dajiang Zheng ◽  
Guang-Ling Song

Purpose The purpose of this paper is to address the concern of some stainless steel users. To understand the effect of surface white spots on corrosion performance of stainless steel. Design/methodology/approach White spots appeared on some component surfaces made of 316 L stainless steel in some industrial applications. To address the concern about the pitting performance in the spot areas, the pitting corrosion potential and corrosion resistance were measured in the spot and non-spot areas by means of potentiodynamic polarization and electrochemical impedance spectroscopy and the two different surface characteristics were analytically compared by using optical microscopy, laser confocal microscopy, scanning electron microscopy, x-ray diffraction, energy dispersive spectroscopy and auger energy spectroscopy. The results indicated that the pitting performance of the 316 L stainless steel was not negatively influenced by the spots and the white spots simply resulted from the slightly different surface morphology in the spot areas. Findings The white spots are actually the slightly rougher surface areas with some carbon-containing species. They do not reduce the pitting resistance. Interestingly, the white spot areas even have slightly improved general corrosion resistance. Research limitations/implications Not all surface contamination or roughening can adversely affect the corrosion resistance of stainless steel. Practical implications Stainless steel components with such surface white spots are still qualified products in terms of corrosion performance. Originality/value The surface spot of stainless steel was systematically investigated for the first time for its effect on corrosion resistance and the conclusion was new to the common knowledge.


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