scholarly journals Electrochemical Analysis of Some Biodegradable Mg-Ca-Mn Alloys

2020 ◽  
Vol 70 (12) ◽  
pp. 4525-4531
Keyword(s):  
Surface Morphology ◽  
Optical Microscope ◽  
Ringer Solution ◽  
Mechanical Tests ◽  
Electrochemical Analysis ◽  
Material Surface ◽  
Electrochemical Tests ◽  
Potential Benefits ◽  
Qualitative Resistance ◽  
Bioresorbable Implants

The potential benefits of magnesium (Mg) over the other non-resorbable biomaterials, especially for orthopedic applications, are obvious. When fully realized, functional bioresorbable implants based on Mg alloys offer the mechanical advantages of a metal combined with the degradable and biological advantages of polymers and biomaterials. <1>In this article we obtained aMg-based prelate alloyed with Ca and Mn. It is known that Mn helps to refine the alloy’s microstructure, which adds to the elasticity of the material. Surface morphology was performed using the optical microscope and the electron microscope while the mechanical tests were performed using the tribometer. Also, the electrochemical tests were executed in the ringer solution. It has been mentioned that the electrochemical resistance is quite low. This study was conducted to determine the corrosion resistance of Mg-Ca-Mn alloys. It has been demonstrated that the addition of Mn refines the microstructure, increases the modulus of elasticity but does not have a qualitative resistance to corrosion.Also, the hardness of the material is quite low in comparison to other pre-alloys of Mg. Keywords: Surface morphology,mechanical tests, electrochemical tests

scholarly journals Influence of the resistive-pulse welding parameters of nickel super-alloys on selected properties of the connection

Mechanik ◽  
2017 ◽  
Vol 90 (11) ◽  
pp. 1060-1062
Author(s):  
Sławomir Spadło ◽  
Wojciech Depczyński ◽  
Piotr Młynarczyk ◽  
Tadeusz Gajewski ◽  
Jarosław Dąbrowa
Keyword(s):  
Optical Microscope ◽  
Mechanical Tests ◽  
Welding Parameters ◽  
Thin Sheets ◽  
Micro Hardness ◽  
Hastelloy X ◽  
Haynes 230 ◽  
Hardness Tester ◽  
Resistive Pulse ◽  
Pulse Welding

Microstructure and mechanical tests of welds of thin sheets made from nickel-based super-alloys (Haynes 230 and Hastelloy X) were presented. The welds were made using the resistive-pulse micro-welding method using the WS 7000S device. The micro-hardness of the joints was measured with a Matsuzawa Vickers MX 100 hardness tester at 100 G (0.98 N). Metallographic observations of the prepared micro-sections were performed using the Nikon Eclipse MA200 optical microscope at various magnifications. The metallographic microstructure studies were supplemented by linear analysis of the chemical composition, for which the OXFORD X-MAX electron microscope was applied.

CHARACTERISATION OF BIOMEDICAL TITANIUM LAYERS DEPOSITED BY A VACUUM PLASMA SPRAY PROCESS

2021 ◽  
Vol 55 (2) ◽  
pp. 231-235
Author(s):  
Mihailo Mrdak ◽  
Darko Bajić ◽  
Darko Veljić ◽  
Marko Rakin
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Hardness Test ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Test Method ◽  
Bonding Layer ◽  
Vacuum Plasma Spray ◽  
Porous Ti ◽  
Scanning Electron

In this paper we will describe the process of the deposition of thick layers of VPS-Ti coating, which is used as a bonding layer for the upper porous Ti coatings on implant substrates. In order to deposit the powder, we used HÖGANÄS Ti powder labelled as AMPERIT 154.086 -63 µm. In order to test the mechanical properties and microstructure of the VPS-Ti coating, the powder was deposited on Č.4171 (X15Cr13 EN10027) steel substrates. Mechanical tests of the microhardness of the coating were performed by the Vickers hardness test method (HV0.3) and tensile strength by measuring the force per unit area (MPa). The microhardness of the coating is 159 HV0.3, which is consistent with the microstructure. The coating was found to have a good bond strength of 68 MPa. The morphology of the powder particles was examined on a scanning electron microscope. The microstructure of the coating, both when deposited and etched, was examined with an optical microscope and a scanning electron microscope. By etching the coating layers, it was found that the structure is homogeneous and that it consists of a mixture of low-temperature and high-temperature titanium phases (α-Ti + β-Ti). Our tests have shown that the deposited layers of Ti coating can be used as a bonding layer for porous Ti coatings in the production of implants.

Mechanical Tests Results of Laser Shock Peening-Treated Austenitic Steel

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Zbyněk Špirit ◽  
Jan Kaufman ◽  
Michal Chocholoušek ◽  
Josef Strejcius
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Mechanical Tests ◽  
Nuclear Industry ◽  
Laser Shock Peening ◽  
Material Surface ◽  
Laser Shock ◽  
Static Properties ◽  
Metallic Material ◽  
Shock Peening

Abstract The presented paper is focused on laser shock-peening technology for hardening the metallic material surface. The material surface hardening improve fatigue performance, static properties, and resistance to stress corrosion cracking of metallic material, which is achieved by creating a pressure residual stress with. The hardening is achieved by shock waves, which are generated by confining the laser-induced plasma to cause a large pressure shock wave over a significant surface area. In the present study, effects of laser shock peening (LSP) on static and dynamic mechanical properties of austenitic stainless steel for nuclear industry were investigated. The tested material was austenitic stainless steel GOST 08CH18N10T (AISI 321H-UNS S32109) for nuclear industry (water–water energetic reactors).

scholarly journals Influence of HIP Treatment on Mechanical Properties of Ti6Al4V Scaffolds Prepared by L-PBF Process

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1267 ◽  
Author(s):  
Lili Liu ◽  
Huade Zheng ◽  
Chunlin Deng
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Oxide Layer ◽  
Critical Stress ◽  
Porous Scaffold ◽  
Optical Microscope ◽  
Post Treatment ◽  
Material Surface ◽  
Porous Scaffolds ◽  
Pressure Test

To improve biocompatibility and mechanical compatibility, post-treatment is necessary for porous scaffolds of bone tissue engineering. Hot isostatic pressing (HIP) is introduced into post-treatment of metal implants to enhance their mechanical properties by eliminating residual stress and pores. Additionally, oxide film formed on the material surface can be contributed to improve its biocompatibility. Ti6Al4V porous scaffolds fabricated by laser-powder bed fusion (L-PBF) process is studied in this paper, their mechanical properties are measured by pressure test, and the macroscopic surface morphology and microstructure are observed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). After HIP treatment, an oxide layer of 0.8 μm thickness forms on the surface of Ti6Al4V porous scaffolds and the microstructure of Ti6Al4V transforms from α’ phase to α + β dual-phase, as expected. However, the pressure test results of Ti6Al4V porous scaffolds show a definitely different variation trend of mechanical properties from solid parts, unexpectedly. Concerning Ti6Al4V porous scaffolds, the compression stiffness and critical stress improves clearly using HIP treatment, and the fracture morphology shows obvious brittle fracture. Both the strengthening and brittleness transition of Ti6Al4V porous scaffolds result from the formation of an oxide layer and an oxygen atom diffusion layer. The critical stress of Ti6Al4V porous scaffolds can be calculated by fully considering these two strengthening layers. To obtain a porous scaffold with specific mechanical properties, the effect of post-treatment should be considered during structural design.

scholarly journals Self-Healable Supramolecular Vanadium Pentoxide Reinforced Polydimethylsiloxane-Graft-Polyurethane Composites

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Ali Berkem ◽  
Ahmet Capoglu ◽  
Turgut Nugay ◽  
Erol Sancaktar ◽  
Ilke Anac
Keyword(s):  
Tensile Strength ◽  
Vanadium Pentoxide ◽  
Coupling Reaction ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Healing Time ◽  
The Self ◽  
Supramolecular Polymer ◽  
Self Healing ◽  
Healing Efficiency

The self-healing ability can be imparted to the polymers by different mechanisms. In this study, self-healing polydimethylsiloxane-graft-polyurethane (PDMS-g-PUR)/Vanadium pentoxide (V2O5) nanofiber supramolecular polymer composites based on a reversible hydrogen bonding mechanism are prepared. V2O5 nanofibers are synthesized via colloidal route and characterized by XRD, SEM, EDX, and TEM techniques. In order to prepare PDMS-g-PUR, linear aliphatic PUR having one –COOH functional group (PUR-COOH) is synthesized and grafted onto aminopropyl functionalized PDMS by EDC/HCl coupling reaction. PUR-COOH and PDMS-g-PUR are characterized by 1H NMR, FTIR. PDMS-g-PUR/V2O5 nanofiber composites are prepared and characterized by DSC/TGA, FTIR, and tensile tests. The self-healing ability of PDMS-graft-PUR and composites are determined by mechanical tests and optical microscope. Tensile strength data obtained from mechanical tests show that healing efficiencies of PDMS-g-PUR increase with healing time and reach 85.4 ± 1.2 % after waiting 120 min at 50 °C. The addition of V2O5 nanofibers enhances the mechanical properties and healing efficiency of the PDMS-g-PUR. An increase of healing efficiency and max tensile strength from 85.4 ± 1.2% to 95.3 ± 0.4% and 113.08 ± 5.24 kPa to 1443.40 ± 8.96 kPa is observed after the addition of 10 wt % V2O5 nanofiber into the polymer.

Electrochemical Properties of Ni-Cr and Co-Cr Alloys Used in Prosthodontics

2011 ◽  
Vol 183 ◽  
pp. 143-148 ◽  
Author(s):  
M. Pochrząst ◽  
Jan Marciniak ◽  
K. Wróbel ◽  
Bohdan Bączkowski
Keyword(s):  
Surface Layer ◽  
Electrochemical Properties ◽  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Electric Circuit ◽  
Material Surface ◽  
Electrochemical Tests ◽  
Solution Interface ◽  
Pitting Corrosion Resistance ◽  
Selection Of

The aim of the work was evaluation of electrochemical properties of Co-based alloys (Remanium GM 800+ and Biosil F) and Ni-based alloys (Heraenium NA and Remanium G-Soft) commonly used on frameworks for porcelain faced cast partial dentures. First stage of the work was evaluation of surface roughness by means of direct linear contact measurement (SURTRONIC 3+ profiler, Taylor/Hobson) of samples after casting and surface treatment. Electrochemical properties of surface were assessed by means of potentiodynamic and impedance methods. In potentiodynamic tests, in order to evaluate pitting corrosion resistance of the analyzed alloys, anodic polarization curves were recorded. The VoltaLab® PGP 201 system was applied in corrosion tests. Moreover, in order to evaluate structure and properties of the surface layer the electrochemical impedance spectroscopy (EIS) was applied. Selection of this method enabled to determine the impedance of the material – surface layer – solution interface with the use of approximation of impedance data by means of equivalent electric circuit model. The EIS tests were carried out with the use of the AutoLab PGSTAT 302N system equipped with the FRA2 Faraday impedance module. Electrochemical tests were carried out in artificial saliva at the temperature of 37°C and pH = 7,0±0,1.

Electrochemical Analysis of the Fluorocarbon Anticorrosion Coating after Accelerated Weathering Environment Aging

2011 ◽  
Vol 239-242 ◽  
pp. 563-566
Author(s):  
Jin Gao ◽  
Wen Juan Yuan ◽  
Xiao Gang Li ◽  
Ying Chao Li ◽  
Wei Zhu
Keyword(s):  
Chemical Structure ◽  
Electrochemical Impedance ◽  
Degradation Process ◽  
Optical Microscope ◽  
Electrochemical Analysis ◽  
Infrared Spectrometry ◽  
Accelerated Weathering ◽  
Xenon Lamp ◽  
Protective Properties ◽  
Corrosion Medium

Fluorocarbon coating was exposed to artificial weathering environment produced by the xenon lamp/condensation weathering equipment for different time periods. The degradation process was studied by electrochemical impedance spectroscopy (EIS), Fourier Transform Infrared Spectrometry (FTIR) and optical microscope. The results show that the resistance of the coatings decrease ，while the capacitance and soakage become larger with the increase of the aging time. This demonstrates that the early aging of the coating influences its protective properties for the corrosion medium. The reason is the changes of the coating’s surface state and chemical structure accelerate the penetration of medium into the coatings, and therefore accelerate the corrosion of metal occurs under the coating.

Synthesis and Characterization of Chrom-Free Dark Coating on AA6063 Aluminium Alloy with K2ZrF6

2014 ◽  
Vol 1053 ◽  
pp. 421-428
Author(s):  
Ting Yi Chen ◽  
Ye Qi Fu ◽  
Wen Lu ◽  
Wen Fang Li
Keyword(s):  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Corrosion Current ◽  
Visual Assessment ◽  
Electrochemical Analysis ◽  
Conversion Coating ◽  
Electrochemical Tests ◽  
Excellent Corrosion Resistance ◽  
New Treatment

A new passivation process has been developed for producing a chrome-free and coloured conversion coating on aluminium alloy AA6063 with K2ZrF6. The conversion coating obtained has a dark film, which enables visual assessment of the coating development and coating quality during processing. The colouring effect is a significant advantage over the zirconium based conversion coatings currently used in the industry, which are largely colourless. The new treatment process is simple and allows a uniform coating to be formed within a few minutes. The composition and the surface morphology of the coatings were characterized. The corrosion resistance of the coated samples was evaluated by electrochemical tests. Through electrochemical analysis, corrosion current of the coatings is low, it has excellent corrosion resistance; SEM, EDS and XRD are used to analyze the process coating.

The Study on the Variation of Friction Coefficient of Flank Lock Type Precision Locknut at the Different Tightening Speed

2014 ◽  
Vol 541-542 ◽  
pp. 588-591 ◽  
Author(s):  
Chih Ming Chen ◽  
Chin Huang Sun
Keyword(s):  
Friction Coefficient ◽  
Surface Morphology ◽  
Fatigue Damage ◽  
Axial Force ◽  
Optical Microscope ◽  
Test Machine ◽  
Experimental Setting ◽  
Thread Surface ◽  
Before And After

The study investigated the variation of friction coefficient of a vertical assembly of flank lock type precision locknut at the different tightening speed by a torque and axial force test machine. The tightening speed is set at 4rpm, 6rpm and 8rpm, respectively. The lubricant is a type of 2TML. Surface morphology was observed before and after the test via an optical microscope. The experiment proceeded to five preloads to test and took the sixth as the experimental setting through the ISO 2320 specification. The study observed the variation of friction coefficient at the different tightening speed under a preload. The results show that the friction coefficient tends to be smaller when the tightening speed becomes faster. The increase of friction coefficient associates with the increase of anti-loosening ratio. For the surface morphology, it was found that the seat surface and the thread surface of the locknut generates the reaming, scraping and fatigue damage after the repeated tightening and loosening test.

The Effects on Microstructure and Hardness of 0.28% Vanadium and 0.87% Nickel Alloyed Ductile Iron after Boronizing Process

2017 ◽  
Vol 740 ◽  
pp. 65-69 ◽  
Author(s):  
Khalissah Muhammad Yusof ◽  
Bulan Abdullah ◽  
Mohd Faizul Idham ◽  
Nor Hayati Saad
Keyword(s):  
Ductile Iron ◽  
Optical Microscope ◽  
Boride Layer ◽  
Holding Time ◽  
Material Surface ◽  
Micro Hardness ◽  
Surface Layers ◽  
Hardness Tester ◽  
Double Phase ◽  
Wear And Corrosion

Boronizing/boriding is a thermo mechanical process which produced protective surface layers to enhance the performance of engineering components utilized in mechanical, wear and corrosion. The present study investigate the microstructure and the hardness of boride layers formed on 0.28% Vanadium and 0.87% Nickel alloyed ductile iron after boronizing process. Specimens were boronized at 950° C for 6, 8 and 10 hours holding time before being cooled in the furnace. The microstructure and boride layer formed on the surface of substrates were observed under Olympus BX60 Optical Microscope. Vickers Micro Hardness Tester was also performed to determine the hardness of boride layers. Boride layer was formed by diffusion of the boron into the metal lattice at the surface which composed double phase of FeB and Fe2B with saw-tooth morphology. The results of this study indicated that the thickness of boride layers increased from 109.8μm at 6 hours to 195.4μm at 8 hours holding time before they crack at 10 hours. The hardness of the material surface also increased from 1535 HV to 1623 HV at 6 and 8 hours respectively. In conclusion, the microstructure, borides thickness and hardness of borides layer were depending on boronizing time while temperature kept constant.

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