scholarly journals Improved Corrosion Resistance of Magnesium Alloy in Simulated Concrete Pore Solution by Hydrothermal Treatment

Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Ye Wang ◽  
Guosong Wu ◽  
Jiapeng Sun
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Hydrothermal Treatment ◽  
Building Materials ◽  
Pore Solution ◽  
Chloride Ions ◽  
Al Alloy ◽  
Natural Immunity ◽  
X Ray ◽  
Building Engineering

Magnesium alloys are considered for building materials in this study due to their natural immunity to corrosion in alkaline concrete pore solution. But, chloride ions attack often hinders the application of most metals. Therefore, it is necessary to conduct a preliminary corrosion evaluation and attempt to find an effective way to resist the attack of chloride ions in concrete pore solution. In our study, hydrothermal treatment is carried out to modify Mg-9.3 wt. % Al alloy. After the treatment in NaOH solution for 10 h, scanning electron microscopy (SEM) reveals that a layer of dense coating with a thickness of about 5 μm is formed on Mg alloy. Energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray Diffraction (XRD) are combined to analyze the coating, and it is thereby confirmed that the coating is mainly composed of Mg(OH)2. As expected, both immersion test and electrochemical corrosion test show that the coated magnesium alloy has a better corrosion resistance than the uncoated one in simulated concrete pore solution with and without chloride ions. In summary, it indicates that hydrothermal treatment is a feasible method to improve the corrosion resistance of Mg alloys used for building engineering from the perspective of corrosion science.

scholarly journals Improving Corrosion Resistance of Magnesium Alloy in Cl- Containing Simulated Concrete Pore Solution by Ultrasound-Assisted Chemical Deposition

Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ye Wang ◽  
Guosong Wu
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Pore Solution ◽  
Chemical Deposition ◽  
Deposition Process ◽  
Cross Sectional ◽  
X Ray ◽  
Electrochemical Tests ◽  
Reaction Solution ◽  
Building Engineering

Coatings are playing an important role in corrosion mitigation of magnesium alloys, and in this study, a facile and eco-friendly chemical deposition process is proposed to improve the corrosion resistance of magnesium-neodymium alloys. The mixture of 1.5 mol/L KH2PO4 solution and 1.2 mol/L CaCl2 solution is used for reaction solution, and ultrasound is introduced into the process for assisting the chemical deposition. After 40 minutes of the surface treatment, the surface and cross-sectional morphologies are observed by scanning electron microscope (SEM), which reveals that a layer of dense coating is formed on Mg alloy. Energy-dispersive X-ray spectroscopy (EDS) and X-ray Diffraction (XRD) are further combined to analyze the coating, and it is thereby confirmed that this coating mainly consists of CaHPO4·2H2O. Electrochemical tests and soaking experiments are conducted to evaluate the corrosion resistance of the treated samples in simulated concrete pore solutions. Both the untreated and treated samples have a good corrosion resistance in the Cl- free simulated concrete pore solution, but their corrosion behavior is influenced by the introduction of Cl- in this study. Fortunately, the coating can protect the substrate effectively in the Cl- containing simulated concrete pore solution. In summary, it provides a possible way for magnesium alloys to improve their corrosion resistance when they are used in building engineering.

scholarly journals Preparation and Characterization of Hydroxyapatite Coating on AZ31 Magnesium Alloy Induced by Carboxymethyl Cellulose-Dopamine

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1849
Author(s):  
Yanxia Yang ◽  
Yuanzhi Wu ◽  
Yu Wei ◽  
Tian Zeng ◽  
Baocheng Cao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Carboxymethyl Cellulose ◽  
Az31 Alloy ◽  
Chloride Ions ◽  
Hydroxyapatite Coating ◽  
X Ray ◽  
Implant Materials ◽  
Good Biocompatibility

Magnesium and its alloys have become potential implant materials in the future because of light weight, mechanical properties similar to natural bone, good biocompatibility, and degradability in physiological environment. However, due to the rapid corrosion and degradation of magnesium alloys in vivo, especially in the environment containing chloride ions, the application of magnesium alloys as implant materials has been limited. Therefore, improving the corrosion resistance of magnesium alloy and ensuring good biocompatibility is the main focus of the current research. In this study, hydroxyapatite coating was prepared on magnesium alloy surface using carboxymethyl cellulose-dopamine hydrogel as inducer to improve corrosion resistance and biocompatibility. Surface characterization techniques (scanning electron microscopy, Fourier-transformed infrared spectroscopy, energy dispersive X-ray spectroscopy- and X-ray diffraction) confirmed the formation of hydroxyapatite on the surface of AZ31 alloy. Corrosion resistance tests have proved the protective effect of Carboxymethyl cellulose-Dopamine/hydroxyapatite (CMC-DA/HA) coating on the surface of AZ31 alloy. According to MC3T3-E1 cell viability and Live/Dead staining, the coating also showed good biocompatibility. The results will provide new ideas for the biological application of magnesium alloys.

Corrosion Resistance by Sodium Metavanadate for AZ91D Magnesium Alloy

2014 ◽  
Vol 575 ◽  
pp. 170-174 ◽  
Author(s):  
Toha Nor Fadzilah ◽  
S. Norbahiyah ◽  
Mohd Zain Mohamad Zamzuri
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Oxide Film ◽  
Corrosion Test ◽  
Energy Dispersive Spectrometry ◽  
Optical Microscope ◽  
X Ray ◽  
Sodium Metavanadate ◽  
Az91d Magnesium Alloy ◽  
Polarization Technique

An oxide film was prepared on AZ91D magnesium alloy by anodizing in solution containing sodium metavanadate (NaVO3). The corrosion resistance of the substrate was investigated at a fixed current density 10 mA/cm2for 5 mins with different concentration of solution in the range of 0 – 1.0 g/l. The surface morphology, phase structure and corrosion resistance of oxide film were studied by optical microscope, scanning electron microscope (SEM) and energy dispersive spectrometry (EDS) and X-ray diffractometer (XRD), potentiodynamic polarization technique and corrosion test.

Einfluss der elektrochemischen Doppelschicht auf die Sorption und den Transport von Chlorionen im Zementstein / Influence of the electrochemical double layer on sorption and transport of chlorides in hardened cement paste

2000 ◽  
Vol 6 (4) ◽  
pp. 415-428
Author(s):  
O. Wowra ◽  
M.J. Setzer
Keyword(s):  
Double Layer ◽  
Cement Paste ◽  
Building Materials ◽  
Pore Solution ◽  
Chloride Ions ◽  
Transport Processes ◽  
Cement Matrix ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Electrochemical Double Layer

Abstract Besides the formation of Friedel salt the transport and binding of chlorides in concrete is mainly defined by the electrochemical double layer at the interface between cement matrix and pore solution. Due to the alkaline pore solution the surface of hardened cement paste is negatively charged which may change to positive values by the potential regulating calcium ions. Inverting of the surface charge leads to an attraction of anions and therefore, to an adsorption of chloride ions in the diffuse part of the electrochemical double layer. Influence from outside like sulphates and carbon dioxide may lead to a decomposition of Friedel salt. Apart from these effect temperature, pH-value and certain environmental conditions affects the electrochemical double layer as well. The chloride equilibrium is mainly controlled by adsorbed ions in the electrochemical double layer. The model presented here is relevant for the assessment of ion transport processes in mineral building materials. Continuing investigations may lead to optimize transport models and a better evaluation of the critical chloride threshold value in reinforced concrete.

Laser Cladding of Zr55Al10Ni5Cu30/SiC Amorphous Composite Coatings on AZ91D Magnesium Alloy for Improvement of Corrosion Resistance

2011 ◽  
Vol 179-180 ◽  
pp. 757-761 ◽  
Author(s):  
Kai Jin Huang ◽  
Hou Guang Liu ◽  
Chang Rong Zhou
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Corrosion Resistance ◽  
Az91d Magnesium Alloy

To improve the corrosion property of magnesium alloys, Zr-based amorphous composite coatings have been fabricated on AZ91D magnesium alloy by laser cladding using mixed powders Zr55Al10Ni5Cu30/SiC. The microstructure of the coating was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion resistance of the coatings was tested in 3.5wt.% NaCl solution. The results show that the coatings mainly consist of amorphous and different crystalline phases. The coatings compared with AZ91D magnesium alloy exhibit good corrosion resistance because of the presence of the amorphous phase in the coatings.

scholarly journals Corrosion Resistance of MgZn Alloy Covered by Chitosan-Based Coatings

2021 ◽  
Vol 22 (15) ◽  
pp. 8301
Author(s):  
Iryna Kozina ◽  
Halina Krawiec ◽  
Maria Starowicz ◽  
Magdalena Kawalec
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Photoelectron Spectroscopy ◽  
Multilayer Coating ◽  
Sem Analysis ◽  
Linear Sweep ◽  
High Corrosion Resistance ◽  
X Ray ◽  
Hank’S Solution

Chitosan coatings are deposited on the surface of Mg20Zn magnesium alloy by means of the spin coating technique. Their structure was investigated using Fourier Transform Infrared Spectroscopy (FTIR) an X-ray photoelectron spectroscopy (XPS). The surface morphology of the magnesium alloy substrate and chitosan coatings was determined using Scanning Electron Microscope (FE-SEM) analysis. Corrosion tests (linear sweep voltamperometry and chronoamperometry) were performed on uncoated and coated magnesium alloy in the Hank’s solution. In both cases, the hydrogen evolution method was used to calculate the corrosion rate after 7-days immersion in the Hank’s solution at 37 °C. It was found that the corrosion rate is 3.2 mm/year and 1.2 mm/year for uncoated and coated substrates, respectively. High corrosion resistance of Mg20Zn alloy covered by multilayer coating (CaP coating + chitosan water glass) is caused by formation of CaSiO3 and Ca3(PO4)2 compounds on its surface.

Durability of cement-based materials in simulated radioactive liquid waste: Effect of phosphate, sulphate, and chloride ions

1998 ◽  
Vol 13 (8) ◽  
pp. 2151-2160 ◽  
Author(s):  
A. Guerrero ◽  
S. Hérnandez ◽  
S. Goñi
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
Pore Solution ◽  
Liquid Waste ◽  
Chloride Ions ◽  
X Ray Diffraction ◽  
Radioactive Liquid Waste ◽  
X Ray ◽  
Medium Level ◽  
Pozzolanic Cement

The durability of a specific backfilling pozzolanic cement mortar, which is employed in Spain, in concrete containers for the storage of low (LLW) and medium level wastes (MLW), has been studied by means of the Köch–Steinegger test at the temperature of 40 °C during a period of 365 days. Mortar samples were immersed in a simulated radioactive liquid waste very rich in sulphate (0.68 M), phosphate (0.89 M), and chloride (0.51 M) ions. The changes of the microstructure were followed by x-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM). Pore solution was extracted at different periods in order to see the changes of the chemical composition caused by the diffusion of those ions inside the microstructure.

scholarly journals Enhanced Corrosion Resistance of SiCp/ 2009 Al by Cerium and Lanthanum Conversion Treatment

2018 ◽  
Vol 778 ◽  
pp. 251-255
Author(s):  
Irfan Aziz ◽  
Qi Zhang
Keyword(s):  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Localized Corrosion ◽  
Al Alloy ◽  
Unreinforced Alloy ◽  
Maximum Increase ◽  
X Ray ◽  
Eds Analysis ◽  
Polarization Studies

The present study investigates the effect of lanthanide chlorides conversion coatings on the corrosion response of the 2009 Al alloy and SiCp reinforced 2009 Al MMCs. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies showed that the localized corrosion resistance increased after treatments with solutions having various combinations of CeCl3.7H2O and LaCl3.7H2O, with maximum increase noticed for 5000ppm CeCl3.7H2O. It was found that the protection degree effect obtained under similar coating conditions for 25 vol.% SiCp/2009 Al was relatively higher than 15vol.% SiCp/ 2009 Al MMC, but both of them were less than that of the unreinforced alloy. Scanning electron microscopy (SEM) accompanied with energy dispersive spectroscopy (EDS) analysis revealed the deposition of Ce and/ or La oxides/ hydroxides on cathodic intermetallics/ SiCp and the existence of crevices at the SiCp/ matrix interfaces. X-ray photoelectron spectroscopy (XPS) results indicated that Ce was incorporated as Ce3+ and Ce4+ species in the coatings.

Investigation on the Dealloying Process of Mn75-xNi25Alx (x=0, 5, 10, 15, 20 at. %) Alloy Ribbons

2018 ◽  
Vol 913 ◽  
pp. 752-758
Author(s):  
Hao Yi Chi ◽  
Yan Wen Bai ◽  
Lu Yao Wang ◽  
Min Zuo
Keyword(s):  
Corrosion Resistance ◽  
Selective Dissolution ◽  
Nanoporous Structure ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Tafel Polarization ◽  
The Impact ◽  
At Will

The main purpose of this study is to investigate the impact of alloy composition and different dealloying condition on the microstructure of the nanoporous Ni. In this paper, Mn75-xNi25Alx(x=0, 5, 10, 15, 20 at. %) alloy ribbons were prepared by single roller rotary quenching system and then further investigated by X-ray Diffraction (XRD). Corrosion resistance was evaluated by means of Tafel polarization. The nanoporous nickel was synthesized by selective dissolution of Mn and Al, which is known as dealloying. The corrosion parameters of dealloying process have been studied in detail. The alloy ribbon developed into amorphous when the Al content reached 15 at.%. According to the Icorr, the corrosion resistance of Mn-Ni-Al alloy ribbons increases with the addition of Al. The addition of Al element, especially when Al content is over 15 at. %, will hinder the dealloying process resulting in the destruction of the nanoporous structure. The dealloying time is also critical to the microstructure of nanoporous nickel obtained. It was found in this work that, during dealloying process, 90 min is insufficient for complete selective dissolution of the active component (Mn and Al). However, the overextended dealloying time of 1440 min time will cause the coarsening destruction of inner porous due to the diffusion of noble element (Ni).

In Situ Formation of ZrO2-Y2O3-Containing Ceramic Coating on Magnesium Alloy by Plasma Electrolytic Oxidation

2011 ◽  
Vol 295-297 ◽  
pp. 1684-1690
Author(s):  
Hai He Luo ◽  
Qi Zhou Cai
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coating ◽  
Electrochemical Corrosion ◽  
Dense Layer ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

A ZrO2-Y2O3-containing composite ceramic coating was firstly in situ prepared on AZ91D magnesium alloy by plasma electrolytic oxidation (PEO) technique in an alkaline silicate-containing electrolyte. The morphology, chemical composition and corrosion resistance of the PEO coating were investigated by environmental scanning electron microscopy (ESEM), X-ray diffractometer (XRD), energy dispersive X-ray (EDX) spectrometer, dropping corrosion and electrochemical corrosion test. The results showed that the ceramic coating consisted of two distinct structural layers: an outer loose layer and an inner dense layer; it was composed of t-ZrO2, Y2O3, SiO2and some magnesium compounds, such as MgO,MgF2and Mg2SiO4. In addition, the ceramic coating also showed excellent dropping and electrochemical corrosion resistance, which was mainly attributed to its special phase composition and microstructure.

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