Microstructure and Corrosion Resistance of Plasma Sprayed Fe-Based Alloy Coating as an Alternative to Hard Chromium

2010 ◽  
Vol 20 (5) ◽  
pp. 1063-1070 ◽  
Author(s):  
Wenhuan Lu ◽  
Yuping Wu ◽  
Jingjing Zhang ◽  
Sheng Hong ◽  
Jianfeng Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Alloy Coating ◽  
Hard Chromium ◽  
Plasma Sprayed

Composite ZrO2-Based Cermet Material Modified with Mo

2015 ◽  
Vol 237 ◽  
pp. 3-8 ◽  
Author(s):  
Adriana Wrona ◽  
Kinga Czechowska ◽  
Małgorzata Osadnik ◽  
Małgorzata Kamińska ◽  
Marcin Lis ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Phase Composition ◽  
Plasma Spraying ◽  
Alloy Coating ◽  
Metallic Material ◽  
Cermet Material ◽  
Powder Composites ◽  
Annealing Procedure ◽  
Plasma Sprayed ◽  
Structure And Microstructure

The work presents studies of a new ceramic-metallic material. The base is a ZrO2-Mo cermet which is modified with metallic Mo or Mo85Re15 alloy coating. The structure and microstructure of Mo85Re15 alloy powders and the composite were characterized. The annealing procedure was found to influence phase composition of powder composites but not their morphology. The plasma sprayed powders, both metallic and alloyed, form coatings that adhere well to the cermet substrate. The coatings show a better homogeneity in comparison to powders and more favourable phase composition.Keywords: cermets, plasma spraying, corrosion resistance

Investigation on the Electrochemical Performance of Plasma Sprayed Ni/Cr-Fe Alloy Coatings in 3.5 %(wt) NaCl Solution

2014 ◽  
Vol 1033-1034 ◽  
pp. 1245-1248
Author(s):  
Xi Shi ◽  
Jun Liang Zhang ◽  
Qi Liang Zhao ◽  
Yi Xiao ◽  
Qing Dong Zhong
Keyword(s):  
Corrosion Resistance ◽  
Chloride Ion ◽  
Alloy Coating ◽  
Corrosion Current ◽  
Double Layers ◽  
Nacl Solution ◽  
Chloride Corrosion ◽  
Initial Stage ◽  
Plasma Sprayed ◽  
Electrochemical Microscopy

Metal material corrosion resistance chloride ion always is a common problem. In order to further study corrosivity of metal materials in chloride solution, in this paper, a double-layers coating consisted of Ni/Cr-Fe alloy which were prepared by plasma sprayed. The morphology and corrosion resistance of that coating in 3.5 % (wt) NaCl solution were investigated by SEM and Scanning Electrochemical Microscopy (SECM). Because coating had some cracks and pores so the coating sample was corroded and the corrosion current increased rapidly in initial stage. After 10 h of immersion, the corrosion current remained stably. Hence, the sample with plasma spraying Ni/Cr-Fe alloy coating had poor chloride corrosion resistance.

Laser Sintering of Nano-Al2O3 Powders on Plasma Sprayed Ceramic Based Coatings

2007 ◽  
Author(s):  
Lida Shen ◽  
Yinhui Huang ◽  
Zongjun Tian ◽  
Guoran Hua
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Plasma Spraying ◽  
Bond Coat ◽  
Continuous Wave ◽  
Ceramic Coatings ◽  
Laser Sintering ◽  
Al2o3 Ceramic ◽  
Plasma Sprayed ◽  
Steel Substrates

This paper describes an investigation of nano-Al2O3 powders reinforced ceramic coatings, which has included NiCrAl and Al2O3+13%wt.TiO2 coats pre-produced by atmosphere plasma spraying, implemented by laser sintering. Commercial NiCrAl powders were plasma sprayed onto 45 Steel substrates to give a bond coat with thickness of ∼100μm. The 600μm thick Al2O3+13%wt.TiO2 based coating was also plasma sprayed on top of the NiCrAl bond coat. With 2.5kw continuous wave CO2 laser, nano-Al2O3 ceramic powders were laser sintered on the based Coatings. The micro structure and chemical composition of the modified Al2O3+13%wt.TiO2 coatings were analyzed by such detection devices as scanning electronic microscope (SEM) and x-ray diffraction (XRD). Microhardness, wear resistance and corrosion resistance of the modified coatings were also tested and compared with that of the unmodified. The results show that the crystal grain size of Al2O3 had no obvious growth. In addition, due to the nanostructured Al2O3 ceramic phases, the coatings exhibited higher microhardness, better wear resistance and corrosion resistance than those unmodified counterparts. The complex process of plasma spraying with laser sintering as a potential effective way of the application of ceramic nano materials was also simply discussed and summarized in the end.

Sealing Treatment of Plasma Sprayed Cr3C2-NiCr/Al2O3-TiO2 Coating by Aluminum Phosphate Sealant Containing Al2O3 Nanoparticles

2021 ◽  
Author(s):  
Tuan Nguyen Van ◽  
Tuan Anh Nguyen ◽  
Ha Pham Thi ◽  
Ly Pham Thi ◽  
Phuong Nguyen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Aluminum Phosphate ◽  
Al2o3 Nanoparticles ◽  
Treatment Efficiency ◽  
Typical Structure ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Sealing Treatment ◽  
Sprayed Coatings

Abstract A typical structure of thermal spray coatings consisted of molten particles, semi-molten particles, oxides, pores and cracks. These factors caused the porosity of sprayed coatings, leading to a great influence on the coating properties, especially their wear-corrosion resistance. In this study, a post-spray sealing treatment of Cr3C2-NiCr/Al2O3-TiO2 plasma sprayed coatings was carried out, then their corrosion properties were evaluated, before and after the treatment. For sealing process, aluminum phosphate (APP) containing aluminum oxide (Al2O3) nanoparticles (~10 nm) was used. The permeability of APP into the sprayed coating was analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The treatment efficiency for porosity and corrosion resistance of sprayed coatings were evaluated by electrochemical measurements, such as the potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, the wear-corrosion resistance of the sealed coating was examined in 3.5 wt.% NaCl circulation solution containing 0.25 wt.% SiO2 particles. The obtained results showed that APP penetrated deeply through the sprayed coating. The incorporation of Al2O3 nanoparticles into APP sealant enhanced the treatment efficiency of porosity for sprayed coating. The effect of the post-treatment on corrosion protection of the sprayed coating has been discussed.

scholarly journals Applying Baghdadite/PCL/Chitosan Nanocomposite Coating on AZ91 Magnesium Alloy to Improve Corrosion Behavior, Bioactivity, and Biodegradability

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 789 ◽  
Author(s):  
Farzad Soleymani ◽  
Rahmatollah Emadi ◽  
Sorour Sadeghzade ◽  
Fariborz Tavangarian
Keyword(s):  
Corrosion Resistance ◽  
Biomedical Applications ◽  
Corrosion Current Density ◽  
Ceramic Coating ◽  
Alloy Coating ◽  
Corrosion Current ◽  
Nanocomposite Coating ◽  
Az91 Alloy ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

Magnesium alloys have received a great amount of attention regarding being used in biomedical applications; however, they show high degradability, poor bioactivity, and biocompatibility. To improve these properties, surface modification and various types of coatings have been applied. In this study, an anodized AZ91 alloy was coated with a polymer matrix composite made of polycaprolactone/chitosan (PCL/Ch) with different percentages of baghdadite to improve its resistance to corrosion, bioactivity, and biocompatibility. The effects of different percentages of baghdadite (0 wt %, 1 wt %, 3 wt %, and 5 wt %) on the surface microstructure, corrosion resistance, roughness, and wettability were evaluated. The results indicated that the applied nano-polymer-ceramic coating including 3 wt % baghdadite was hydrophobic, which consequently increased the corrosion resistance and decreased the corrosion current density of the anodized AZ91 alloy. Coating with 3 wt % baghdadite increased the roughness of AZ91 from 0.329 ± 0.02 to 7.026 ± 0.31 μm. After applying the polymer-ceramic coating on the surface of anodized AZ91, the corrosion products changed into calcium–phosphate compounds instead of Mg(OH)2, which is more stable in a physiological environment.

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