scholarly journals Investigation of Corrosion Resistance Enhancement for Biodegradable Magnesium Alloy by Ball Burnishing Process

2020 ◽  
Vol 14 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Chenyao Cao ◽  
Jiang Zhu ◽  
Tomohisa Tanaka ◽  
Dinh Ngoc Pham ◽  
◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Mass Loss ◽  
Immersion Test ◽  
Corrosion Products ◽  
Mg Alloys ◽  
Surface Finishing ◽  
Human Organism ◽  
Corrosion Mechanism ◽  
Ball Burnishing ◽  
Treated Sample

Magnesium and magnesium-based alloys are considered ideal materials for implants in orthopedic treatment because their stiffness is close to that of human bones, and they can be absorbed gradually in the human organism. However, a major issue in their actual application is that the corrosion speed of Mg alloys is very high in aggressive environments such as the human fluids. In previous studies, many approaches have been attempted to enhance the corrosion resistance of Mg alloys. In this research, ball burnishing, a mechanical surface finishing process, is applied to improve the corrosion resistance of Mg alloys by changing its surface properties. The influence of the burnishing parameters on the corrosion resistance is investigated, and the corrosion of a treated and non-treated sample are compared. The test material used is the AZ31 Mg alloy. Firstly, a comprehensive review of the effect of burnishing on the final microstructures is reported. The influence of burnishing on grain size, work-hardened layer thickness, crystal orientation, and residual stress of the sample is discussed. Secondly, by conducting an especially designed long-term immersion test, the mass loss and surface evolution of each sample are evaluated. The experimental results indicate that, under proper processing conditions, the mass loss of the treated sample (8.8 mg) can be reduced to 36% of the non-treated one (24.2 mg). To elucidate the mechanism behind corrosion resistance enhancement by burnishing, the samples treated with the optimal processing parameters found are immersed in an aggressive solution for 1, 3, 5, and 7 days. From the results of mass loss measurement and surface structure characterization, it was found that, among pitting, general, and intergranular corrosion, pitting corrosion is the dominant corrosion mechanism. The holes enlarge because pits combine together, representing the greatest portion of mass loss. The main mechanism enhancing corrosion resistance is the size reduction of the grains on the surface induced by ball burnishing, causing a denser distribution of corrosion products in the immersion test. These corrosion products protect the material underneath accelerated corrosion.

scholarly journals Structure and Corrosion Behavior of TiO2 Thin Films Deposited by ALD on a Biomedical Magnesium Alloy

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 70
Author(s):  
Aneta Kania ◽  
Magdalena M. Szindler ◽  
Marek Szindler
Keyword(s):  
Thin Films ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Magnesium Alloys ◽  
Corrosion Behavior ◽  
Atomic Layer ◽  
Immersion Test ◽  
Mg Alloys ◽  
Tio2 Films ◽  
Tio2 Thin Films

Magnesium alloys have been investigated as temporary biomaterials for orthopedic applications. Despite their high osseointegration and mechanical (bone-like) properties, Mg alloys quickly degrade in simulated physiological media. Surface coatings can be deposited onto Mg alloys to slow the corrosion rate of these biomaterials in chloride-rich environments. TiO2 films show high potential for improving the corrosion resistance of magnesium alloys. This article presents the structural observations and corrosion behavior of TiO2 thin films deposited onto a MgCa2Zn1Gd3 alloy using atomic layer deposition (ALD). Surface morphologies were observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and Raman analysis of the deposited TiO2 films was also carried out. The corrosion behavior of the uncoated alloy and the alloy coated with TiO2 was measured in Ringer’s solution at 37 °C using electrochemical and immersion tests. The microscopic observations of the TiO2 thin films with a thickness of about 52.5 and 70 nm showed that the surface morphology was homogeneous without visible defects on the TiO2 surface. The electrochemical and immersion test results showed that the thin films decreased the corrosion rate of the studied Mg-based alloy, and the corrosion resistance was higher in the thicker TiO2 film.

scholarly journals Effect of Sodium Phosphate and Calcium Nitrate Sealing Treatment on Microstructure and Corrosion Resistance of Wire Arc Sprayed Aluminum Coatings

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 33 ◽  
Author(s):  
Han-Seung Lee ◽  
Ashutosh Kumar ◽  
Soumen Mandal ◽  
Jitendra Kumar Singh ◽  
Fahid ASLAM ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Sodium Phosphate ◽  
Volume Fraction ◽  
Steel Substrate ◽  
Calcium Nitrate ◽  
Post Treatment ◽  
Corrosion Products ◽  
Transfer Resistance ◽  
Treated Sample ◽  
Al Coating

Aluminum coating was deposited by arc thermal spraying process onto the steel substrate for the corrosion protection in aggressive environment. However, the arc thermal sprayed coating possesses defects in the coating. Thus, it is important to reduce the defects and enhance the corrosion resistance properties of the deposited coating using post-treatment. In the present study, we have used different concentrations of sodium phosphate mono basic (NaH2PO4) with 0.1 molar (M) calcium nitrate [Ca(NO3)2] as post-treatment solution to fill out the defects of the Al coating. It was observed by scanning electron microscopy (SEM) that 1 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample exhibited 71% reduction in defects compared to as coated samples. X-ray diffraction (XRD) was performed to determine the phases formed on the coating surface after treatments. XRD confirms the formation of sodium aluminum hydrogen phosphate (Na3Al(OH)(HPO4)(PO4)) and brushite (Ca(HPO4)(H2O)2) as composite oxides on the Al coating. Electrochemical results show that 0.5 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample has exhibited the highest charge transfer resistance and the lowest corrosion current density after 89 days of exposure in 3.5 wt.% NaCl solution. The enhancement in corrosion resistance of 0.5 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample attributed to the formation of adherent, sparingly soluble, and stable corrosion products. The volume fraction result of the corrosion products formed on 0.5 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample after 89 days of exposure in 3.5 wt.% NaCl using XRD confirms the highest amount of Bayerite (α-Al(OH)3) deposition, thus, the corrosion rate of this sample was the lowest.

scholarly journals Ca and Ce Effect on the Corrosion Resistance of Hot-Rolled AZ31 Mg Alloys

2020 ◽  
Vol 10 (1) ◽  
pp. 5113-5116
Author(s):  
I. H. Kara ◽  
T. A. I. Yousef ◽  
H. Ahlatci ◽  
Y. Turen
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Test ◽  
Die Casting ◽  
Immersion Test ◽  
Mg Alloys ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Low Pressure Die Casting ◽  
Hot Rolled ◽  
Pressure Die Casting

In this study, AZ31 Mg alloys with added Ca and Ce were produced by low pressure die casting and were rolled at 400°C. The corrosion properties of the materials were determined by immersion test for 72 hours at a 3.5% NaCl solution. The microstructure of the samples was investigated by light optical microscopy (LOM) and scanning electron microscopy (SEM) before the corrosion test. Twins, dynamic recrystallization (DRX), and the alloying elements have an important role in imparting the final corrosion resistance of the investigated materials.

Microstructure and Corrosion Behavior of AZ91-0.4%Nd Magnesium Alloy

2013 ◽  
Vol 291-294 ◽  
pp. 2577-2580 ◽  
Author(s):  
Ju Mei Zhang ◽  
Zhi Hu Wang ◽  
Wan Chang Sun ◽  
Ming Zhu
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Immersion Test ◽  
Corrosion Products ◽  
Grain Refining ◽  
Az91 Magnesium Alloy ◽  
Refining Efficiency ◽  
Phase Precipitate ◽  
Az91 Magnesium

The corrosion behavior of AZ91-0.4%Nd alloys was investigated by immersion test in 3.5wt.% NaCl at 25°C. The phase compositions and microstructure of the AZ91-0.4%Nd alloy were characterized by XRD and OM, respectively. The results show that the number of Nd element in the AZ91 magnesium alloy has effect on the grain refining efficiency, and the granular or acicular Al3Nd phase precipitate in matrix.The corrosion products of the AZ91-0.4%Nd alloy mainly composed of Mg(OH)2and Al. The addition of Nd element significantly refine the microstructure and improve the compactness of corrosion products of AZ91-0.4%%Nd magnesium alloy, as a result the corrosion resistance of alloy was improved obviously.

scholarly journals Effects of Different Rare Earth Elements on the Degradation and Mechanical Properties of the ECAP Extruded Mg Alloys

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 627
Author(s):  
Junxiu Chen ◽  
Jie Zhan ◽  
Sharafadeen Kunle Kolawole ◽  
Lili Tan ◽  
Ke Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Microstructural Characterization ◽  
Immersion Test ◽  
Mg Alloys ◽  
Cytotoxicity Test ◽  
Angular Pressing ◽  
Yttrium Addition

Effects of different rare earth elements on the degradation and mechanical properties of the ECAP (equal channel angular pressing) extruded Mg alloys were investigated in this work. Microstructural characterization, thermodynamic calculation, a tensile test, an electrochemical test, an immersion test, a hydrogen evolution test and a cytotoxicity test were carried out. The results showed that yttrium addition was beneficial to the improvement of the alloy’s strength, and the ultimate tensile strength (UTS) and yield strength (YS) values of the ECAPed Mg-2Zn-0.5Y-0.5Zr alloy reached 315 MPa and 295 MPa, respectively. In addition, Nd was beneficial to the corrosion resistance, for which, the corrosion rate of the ECAPed Mg-2Zn-0.5Nd-0.5Zr alloy was observed to be 0.42 ± 0.04 mm/year in Hank’s solution after 14 days of immersion. Gd was moderate in improving both the corrosion resistance and mechanical properties. Moreover, after co-culturing with murine calvarial preosteoblasts (MC3T3-E1) cells, the ECAPed Mg-2Zn-0.5RE (Nd, Gd, Y)-0.5Zr alloys exhibited good cytocompatibility with a grade 1 cytotoxicity. Consequently, the ECAPed Mg-2Zn-0.5Nd-0.5Zr alloy showed the best application prospect in the field of orthopedics.

Progress on Hydrothermal Synthesis of Biomedical Coatings on Magnesium Alloy

2015 ◽  
Vol 816 ◽  
pp. 424-432
Author(s):  
Guang Hui Guo ◽  
Jing Hua Jiang ◽  
Dan Song ◽  
Ai Bin Ma ◽  
Li Li Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Hydrothermal Synthesis ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Mg Alloys ◽  
Synthesis Process ◽  
Corrosion Mechanism ◽  
Research Prospect ◽  
Biomedical Coatings ◽  
Biomedical Coating

Hydrothermal synthesis as a new coating technique has been developed to produce biomedical coating in Mg alloys in recent years. This paper summarized the process feature and corrosion resistance of hydrothermal synthesis coating in Mg alloys, and then reviewed the synthesis process, microstructure, corrosion behavior and corrosion mechanism of the Mg (OH)2 biomedical coatings. Finally, the current problems and research prospect of this technique in biomedical Mg alloys were discussed.

scholarly journals Effect of Oxide Scale Microstructure on Atmospheric Corrosion Behavior of Hot Rolled Steel Strip

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 517
Author(s):  
Bin Sun ◽  
Lei Cheng ◽  
Chong-Yang Du ◽  
Jing-Ke Zhang ◽  
Yong-Quan He ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Scale ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Atmospheric Corrosion ◽  
Corrosion Mechanism ◽  
Type I ◽  
Rust Layer ◽  
Hot Rolled

The atmospheric corrosion behavior of a hot-rolled strip with four types (I–IV) of oxide scale was investigated using the accelerated wet–dry cycle corrosion test. Corrosion resistance and porosity of oxide scale were studied by potentiometric polarization measurements. Characterization of samples after 80 cycles of the wet–dry corrosion test showed that scale comprised wüstite and magnetite had strongest corrosion resistance. Oxide scale composed of inner magnetite/iron (>70%) and an outer magnetite layer had the weakest corrosion resistance. The corrosion kinetics (weight gain) of each type of oxide scale followed an initial linear and then parabolic (at middle to late corrosion) relationship. This could be predicted by a simple kinetic model which showed good agreement with the experimental results. Analysis of the potentiometric polarization curves, obtained from oxide coated steel electrodes, revealed that the type I oxide scale had the highest porosity, and the corrosion mechanism resulted from the joint effects of electrochemical behavior and the porosity of the oxide scale. In the initial stage of corrosion, the corrosion product nucleated and an outer rust layer formed. As the thickness of outer rust layer increased, the corrosion product developed on the scale defects. An inner rust layer then formed in the localized pits as crack growth of the scale. This attacked the scale and expanded into the substrate during the later stage of corrosion. At this stage, the protective effect of the oxide scale was lost.

Improving Corrosion Resistance of Hot Extruded Mg-Sn-Al-Ce Magnesium Alloy by Rapid Solidification

2017 ◽  
Vol 904 ◽  
pp. 80-84 ◽  
Author(s):  
Peng Cheng ◽  
Yun Gui Chen ◽  
Wu Cheng Ding
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Rapid Solidification ◽  
Corrosion Behavior ◽  
Corrosion Products ◽  
Uniform Particles

The corrosion behavior and microstructure of hot extruded Mg-5 wt.%Sn-4 wt.%Al-2 wt.%Ce alloy by rapid solidification ribbon (RS-EX TAE542) are investigated. The results shows that corrosion resistance of RS-EX alloy is remarkably improved, compared with that of hot extruded TAE542 alloy by homogenized ingot (HI-EX TAE542). Relatively compact corrosion products and bedded corrosion surface of RS-EX alloy is connected with the fine grains and uniform particles caused by rapid solidification, and they can suppress the corrosion reactions.

Leaching of Am-241 from a Radioactive Waste Glass Corroded in the Presence of Stainless Steel Corrosion Products and/or Bentonite

1987 ◽  
Vol 112 ◽  
Author(s):  
Masaki Tsukamoto ◽  
Inga-Kari Björner ◽  
Hilbert Christensen ◽  
Hans-Peter Hermansson ◽  
Lars Werme
Keyword(s):  
Stainless Steel ◽  
Radioactive Waste ◽  
Mass Loss ◽  
Total Mass ◽  
Corrosion Behaviour ◽  
Steel Corrosion ◽  
Waste Glass ◽  
Corrosion Products ◽  
Total Mass Loss ◽  
Elemental Mass

AbstractThe release of Am-241 during corrosion of the radioactive waste glass, JSS-A, has been studied in the presence of corrosion products and/or uncom-pacted bentonite. The corrosion behaviour of Am-241 has been analyzed using gamma spectrometry. Adsorption of Am-241 on bentonite is observed in all cases. The contents of Am-241 in centrifuged leachates are in most cases less than 1/100 of total values. The normalized elemental mass loss of Am increases initially with corrosion time, and the values in the presence of bentonite and corrosion products are larger than those in the presence of bentonite alone. This tendency is in agreement with results previously found for other elements. The release of Am is low, only about 10–20 % of the corresponding total mass loss.

Adhesion and Corrosion Resistance Properties of TiC/Ti(CN)/TiN Multilayer CVD Coatings on 42CrMo Steels

2009 ◽  
Vol 79-82 ◽  
pp. 1009-1012
Author(s):  
Jin Zhang ◽  
Qi Xue ◽  
Xiao Wei Cheng ◽  
Chun Mei Zhang ◽  
Song Xia Li
Keyword(s):  
Corrosion Resistance ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Fracture Morphology ◽  
Immersion Test ◽  
Multilayer Films ◽  
Multilayer Coatings ◽  
Cvd Method ◽  
42Crmo Steel ◽  
Immersion Corrosion

The TiC/Ti(CN)/TiN multilayer coatings were deposited on 42CrMo steel by chemical vapor deposition (CVD) method. The fracture morphology,structure,microhardness and adhesion of the coatings were analyzed. The immersion test in simulant solution with H2S,CO2 at 100°C and electrochemistry test in 20wt% H2SO4 at room temperture were applied to investigate the corrosion resistance of the multilayer films.The results reveal that the multilayer coatings can offer 42CrMo steel higher corrosion resistance,especially the immersion corrosion test.The corrosion rate of the samples coated with CVD multilayer films is reduced more 70 times than that of the uncoated and samples by quenching-polishing-quenching (QPQ) treat.

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