The evaluation of microstructure characteristic and corrosion performance of laser-re-melted Fe-based amorphous coating deposited via plasma spraying

2019 ◽  
Vol 9 (9) ◽  
pp. 1100-1105
Author(s):  
Xiao-Lin Zhang ◽  
Chao-Ping Jiang ◽  
Feng-Ying Zhang ◽  
Ya-Zhe Xing

The laser re-melting treatment was performed on the plasma-sprayed Fe-based amorphous coating to ameliorate the corrosion performance of the coating. The re-melting depth was about 200 μm which was mainly controlled by laser energy input, beam speed and facular dimension. The microstructure was characterized by scanning electron microscope (SEM), and X-ray diffraction (XRD). The corrosion property of the coatings was addressed via electrochemistry methods in a 3.5 wt.% NaCl solution. The results indicate that the plasma-sprayed coating becomes much denser after laser re-melting treatment. The connected porosity ratio in as-sprayed coating dramatically reduces from 16.3% to 2.4% after laser re-melting. The as-sprayed coating mainly contains amorphous and much limited crystal phase, and some amorphous phase in the as-sprayed coating crystalizes during laser re-melting. Polarization test demonstrated that the as-sprayed coating has a significantly dramatical effect for improving corrosion performance of carbon steel, while the laser re-melting process is a more efficient method. The influence level of the coating compactness in this study is roughly two times as big as that of amorphous in coating, in the term of improving corrosion resistance of carbon steel.

2015 ◽  
Vol 9 (1) ◽  
pp. 42-55 ◽  
Author(s):  
Imane Demnati ◽  
David Grossin ◽  
Olivier Marsan ◽  
Ghislaine Bertrand ◽  
Gérard Collonges ◽  
...  

Chlorapatite can be considered a potential biomaterial for orthopaedic applications. Its use as plasma-sprayed coating could be of interest considering its thermal properties and particularly its ability to melt without decomposition unlike hydroxyapatite. Chlorapatite (ClA) was synthesized by a high-temperature ion exchange reaction starting from commercial stoichiometric hydroxyapatites (HA). The ClA powder showed similar characteristics as the original industrial HA powder, and was obtained in the monoclinic form. The HA and ClA powders were plasma-sprayed using a low-energy plasma spraying system with identical processing parameters. The coatings were characterized by physical-chemical methods, i.e. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, including distribution mapping of the main phases detected such as amorphous calcium phosphate (ACP), oxyapatite (OA), and HA or ClA. The unexpected formation of oxyapatite in ClA coatings was assigned to a side reaction with contaminating oxygenated species (O2, H2O). ClA coatings exhibited characteristics different from HA, showing a lower content of oxyapatite and amorphous phase. Although their adhesion strength was found to be lower than that of HA coatings, their application could be an interesting alternative, offering, in particular, a larger range of spraying conditions without formation of massive impurities.


2007 ◽  
Vol 544-545 ◽  
pp. 451-454
Author(s):  
Soo Wohn Lee ◽  
Jia Zhang ◽  
Huang Chen ◽  
J. S. Song ◽  
Jae Kyo Seo ◽  
...  

Plasma sprayed coatings have been widely applied in modifying surface properties of metal components. It is also useful to prevent various types of wear, corrosion, erosion and thermal. But the residual stress is still an important problem which can effect the properties of sprayed coating. So it’s necessary to find out the reason of residual stress and the relationship between plasma sprayed condition and residual stress. Plasma spray coating layers with conventional ZrO2 powder was examined to calculate residual stress by X-ray diffraction method with various coating thickness.


2012 ◽  
Vol 463-464 ◽  
pp. 420-424
Author(s):  
San Ming Du ◽  
Yong Ping Niu ◽  
Yong Zhen Zhang

In the present study, 20 Wt. % ZrO2-Al2O3-17 wt.% TiO2 powders were sprayed using a plasma-spray technique after a NiAl bond layer was deposited on plain carbon steel substrate. The produced coatings were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) including energy-dispersive spectroscopy (EDS). The tribological properties of coatings against hard alloy ball were investigated by using a pin-on-disc tribo-meter under dry environments. The predominant wear mechanism of coating is fatigue.


2008 ◽  
Vol 15 (06) ◽  
pp. 815-819
Author(s):  
SHIBIN SUN ◽  
ZENGDA ZOU ◽  
XUEMEI LIU ◽  
HANCHAO SHI

TiC -based wear resistant coating was prepared by plasma spraying using reconstituted composite powders doped with ultra-fine carbide. Phase composition and microstructure of as-sprayed coating were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) utilizing backscattered imaging mode (BSE), and electron probe micro-analysis. Wear test was performed by using a ring-on-block tester under dry sliding condition. Results show that the coating adheres well to the substrate and no delamination appears. TiC content underwent pronounced reduction because of oxidation, reaction, and physical loss. Reactions between TiC and Mo and probably between dissociated C and Mo lead to the formation of Mo 2 C . Wear resistance of NiCrMo – TiC coating is about 4–8 times higher than that of substrate under different applied force. This work shed light on the reconstitution of spraying powder doped with ultra-fine reinforce phase particles, and the present results are important for the preparation of nano-doped TiC -based coatings.


2007 ◽  
Vol 330-332 ◽  
pp. 1301-1304 ◽  
Author(s):  
Cheng Yun Ning ◽  
Ying Jun Wang ◽  
Xiao Feng Chen ◽  
Jian Dong Ye ◽  
Gang Wu ◽  
...  

In the present study, Functionally gradient HA-ZrO2-Ti coatings (FGC) on Ti6Al4V were prepared by the plasma spraying process. The residual stress and surfacial morphology of coating were studied by X-ray diffraction and scanning electron microscopy with an energy dispersive spectroscopy. The results showed that: (1) the residual stress of FGC is 72.1Mpa, much lower than that of single HA coating, (2) The surfacial morphology of the FGC showed typical characteristics of plasma-sprayed coating, no microcracks was observed because of its the thermal expansion matched between the gradient coating and substrate.


2019 ◽  
Vol 296 ◽  
pp. 161-166
Author(s):  
David Jech ◽  
Michaela Remešová ◽  
Pavel Komarov ◽  
Serhii Tkachenko ◽  
Zdeněk Česánek ◽  
...  

Only a few types of commercially available high temperature ceramic abradable coatings are presented on the market and most of them consist of partially stabilized yttria zirconia with polymer porosity former agent and/or hBN solid lubricant. The basic demand placed on abradable coatings include balance between hardness and erosion resistance. The contribution focuses on the description of microstructure, phase composition and hardness of alternative atmospheric plasma sprayed ceramic abradable coatings deposited from four different experimental powder mixtures: (i) commercial yttria-zirconia + 5 wt. % of experimental BaF2/CaF2, (ii) commercial yttria stabilized zirconia + 10 wt. % of experimental BaF2/CaF2, (iii) R&D powder SrxTiOy and (iv) R&D powder SrxTiOy + 5 wt. % of polyester. The abradable coating systems were of ~ 150 μm thick CoNiCrAlY bond coat and of ~ 800-1000 μm thick ceramic top coat. The microstructure and phase composition of all atmospheric plasma sprayed coating systems were evaluated by the means of scanning electron microscopy and X-ray diffraction techniques. To estimate coatings basic parameters the Rockwell hardness HR15Y was measured.


2015 ◽  
Vol 08 (05) ◽  
pp. 1550018 ◽  
Author(s):  
Shupeng Liu ◽  
Na Chen ◽  
Fufei Pang ◽  
Zhengyi Chen ◽  
Tingyun Wang

Purpose: This work focused on the investigation the hyperthermia performance of the carbon-coated magnetic particles (CCMPs) in laser-induced hyperthermia. Materials and methods: We prepared CCMPs using the organic carbonization method, and then characterized them with transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectrophotometry, vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). In order to evaluate their performance in hyperthermia, the CCMPs were tested in laser-induced thermal therapy (LITT) experiments, in which we employed a fully distributed fiber Bragg grating (FBG) sensor to profile the tissue's dynamic temperature change under laser irradiation in real time. Results: The sizes of prepared CCMPs were about several micrometers, and the LITT results show that the tissue injected with the CCMPs absorbed more laser energy, and its temperature increased faster than the contrast tissue without CCMPs. Conclusions: The CCMPs may be of great help in hyperthermia applications.


2021 ◽  
Vol 800 ◽  
pp. 140249
Author(s):  
Juan Macchi ◽  
Steve Gaudez ◽  
Guillaume Geandier ◽  
Julien Teixeira ◽  
Sabine Denis ◽  
...  

1990 ◽  
Vol 191 ◽  
Author(s):  
Michael E. Geusic ◽  
Alan F. Stewart ◽  
Larry R. Pederson ◽  
William J. Weber ◽  
Kenneth R. Marken ◽  
...  

ABSTRACTExcimer laser ablation with an in situ heat treatment was used to prepare high quality superconducting YBa2Cu3O7−x thin films on (100)-SrTiO3 and (100)-LaAlO3 substrates. A pulsed excimer laser (XeCl; 308 nm) was used to ablate a rotating, bulk YBa2Cu3O7−x target at a laser energy density of 2–3 J/cm2. Based on four-probe dc resistance measurements, the films exhibited superconducting transition temperatures (Tc, midpoint) of 88 and 87K with 2K (90–10%) transition widths for SrTiO3 and LaAlO3, respectively. Transport critical current densities (Jc) measured at 77K were 2 × 106 and 1 × 106 A/cm2 in zero field for SrTiO3 and LaAlO3, respectively. X-ray diffraction (XRD) analysis showed the films to be highly oriented, with the c-axis perpendicular to the substrate surface.


2005 ◽  
Vol 20 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Y.X. Yin ◽  
H.M. Wang

Wear-resistant Cu-based solid-solution-toughened Cr5Si3/CrSi metal silicide alloy with a microstructure consisting of predominantly the dual-phase primary dendrites with a Cr5Si3 core encapsulated by CrSi phase and a small amount of interdendritic Cu-based solid solution (Cuss) was designed and fabricated by the laser melting process using Cr–Si–Cu elemental powder blends as the precursor materials. The microstructure of the Cuss-toughened Cr5Si3/CrSi metal silicide alloy was characterized by optical microscopy, powder x-ray diffraction, and energy dispersive spectroscopy. The Cuss-toughened silicide alloys have excellent wear resistance and low coefficient of friction under room temperature dry sliding wear test conditions with hardened 0.45% C carbon steel as the sliding–mating counterpart.


Sign in / Sign up

Export Citation Format

Share Document