A Study of PM Mg-HAP Composite: Corrosion and Microstructural Evaluation

2015 ◽  
Vol 754-755 ◽  
pp. 998-1001 ◽  
Author(s):  
Zuraidawani Che Daud ◽  
Faliq bin Fuad ◽  
M. Nazree Derman
Keyword(s):  
Powder Metallurgy ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Optical Microscope ◽  
Alloy Sample ◽  
Biomedical Implant ◽  
Hydroxyapatite Particle ◽  
Surrounding Environment ◽  
Microstructural Evaluation

Mg-HAP Composite produce by powder metallurgy (PM) methods is one new biomaterial usually applied as biomedical implant. However, the sensitive Mg metal to surrounding environment is giving the bad impact for this biomaterial because of the presence hydroxyapatite particle in Mg matrix. The aim of this work is to study the corrosion behavior and microstructural evaluation of composite biomaterial Mg with different percentage of Hyroxyapatite (HAP) (5, 10, 15 and 20 wt. %) produced by powder metallurgy (PM) method. The corrosion test was done using electrochemical methods and the microstructure after corrosion test was observed using optical microscope. Based on the results, the different percentages of HAP were influenced the corrosion rate of the Mg-HAP composite. The percentage of HAP content in Mg were greatly influences the corrosion behavior of the alloy. Sample Mg-20wt% HAP has the lowest corrosion rate which is 0.16mm per year, while sample Mg-15wt% HAP has the highest corrosion rate, 0.37 mm per year.

scholarly journals Corrosion Behavior of Zinc-Graphite Metal Matrix Composite in 1 M of HCl

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
M. A. Afifi
Keyword(s):  
Corrosion Resistance ◽  
Electron Microscope ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Metal Matrix ◽  
Optical Microscope ◽  
Powder Metallurgy Method ◽  
Pure Zinc ◽  
Graphite Composites ◽  
Scanning Electron

This paper is aimed at investigating the corrosion behavior of Pure and Zinc-graphite particles with percentage of 1, 3, and 5%, respectively. The composites were fabricated by powder metallurgy method. Corrosion tests were performed according to ASTM standard. Corrosion rate was calculated and it is found that in all cases the corrosion rate was decreasing with the increase in exposure time. Meanwhile, the microstructure of composites was imaged and analyzed using optical microscope and scanning electron microscope. It is observed that the best corrosion resistance was zinc with 1% Graphite while Zinc with 3% and 5% Graphite composites did not enhance the corrosion resistance comparing to pure Zinc.

Corrosion Behavior of Fe-Mn-C Alloy as Degradable Materials Candidate Fabricated via Powder Metallurgy Process

2012 ◽  
Vol 576 ◽  
pp. 386-389 ◽  
Author(s):  
Sri Harjanto ◽  
Yudha Pratesa ◽  
Bambang Suharno ◽  
Junaidi Syarif
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Austenite Phase ◽  
Coronary Stents ◽  
Powder Metallurgy Process ◽  
Degradable Biomaterials ◽  
Degradable Materials ◽  
Metallurgy Process

Fe-Mn alloys are prospective degradable materials for coronary stents. Several methods and strategies are investigated to produce excellence properties for this application, such as addition of alloying elements. The study is focused on the corrosion behavior of novel Fe-Mn alloys, i.e. Fe-25Mn-1C and Fe-35Mn-1C fabricated by powder metallurgy process. Addition of carbon is intended to obtain the phase that has ability to easily degradable without compromising its mechanical properties. The results show that austenite phase formed from this process and corrosion rate increased in proportion with the manganese addition from 32.2 mpy (Fe-25Mn-1C) to 43.7 mpy (Fe-35Mn-1C) using polarization methods. The presence of porosity, which cannot be extinguished by sintering, makes the degradation favorable. The results of this study indicate that these alloys have prospective properties to be applied as degradable biomaterials.

scholarly journals To Investigate the Effect of Heat Treatment on Low Carbon Steel Corrosion Behavior

2018 ◽  
Vol 7 (3.20) ◽  
pp. 412
Author(s):  
Azhar Wahab Abdalrhem ◽  
Ali Jaber Naeemah ◽  
Makki Noori jawad
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Low Carbon Steel ◽  
Steel Corrosion ◽  
Optical Microscope ◽  
Polarization Measurement ◽  
Material Surface ◽  
Low Carbon

This work was to investigating the corrosion behavior of low carbon steel in a salt solution of 3.5wt% NaCl after undergoing two different types of heat treatment at 960 ºC in a furnace. The material of low carbon steel was cut into nine small pieces under three groups A, B and C, without heated annealing and hardening heat treatment respectively. The heat treatment was at temperature 960ºC. The hardness of the sample as received will be 203 kg/mm2 while after hardening the hardness was increased. The sample was mounted using hot and cold mounting. The microstructure and surface morphology was observed by using Scanning Electron Microscope (SEM) and Optical Microscope (OM) after grinding, polishing and etching on the sample. In group A cementite can be observed clearly on pearlite on the surface before corrosion test. After four days soaking in 3.5 wt% NaCl solution was observed all cementite and pearlite will be transformed to austenite with the remnants of cementite make the surface unstable hence increases the initial corrosion. After four days soaking when the cementite is oxidized and a thick film of corrosion product covers the material surface. The formation of Martensite due to quenching and rapid cooling in group C sample increases the corrosion rate from 0.072 mpy to 0.302 due to decreased of corrosion potential from -572 mV to -639 mV after four days soaking. The corrosion rate of each sample was measured by using electrochemical polarization measurement and Tafel extrapolation technique. From previous result, it was observed that samples which had undergone annealing mode of heat treatment turned out to be the ones with the best corrosion resistance.  

Corrosion Behavior of a Predeformed Fe-Ni Lateritic Steel with Bainite Structure

2020 ◽  
Vol 867 ◽  
pp. 8-16
Author(s):  
Miftakhur Rohmah ◽  
Moch. Syaiful Anwar ◽  
Rahadian Roberto ◽  
Fatayalkadri Citrawati
Keyword(s):  
Corrosion Rate ◽  
Cold Rolling ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Test Method ◽  
Railway Track ◽  
Air Cooling ◽  
Corrosion Properties ◽  
Train Station ◽  
Bainite Structure

In a railway track for intermodal usage between a train station to a port, an observation on corrosion behavior of the track alloy in the coastal environment needs to be considered. In this study, Fe-Ni lateritic steel with bainite structure is observed. This alloy is developed from lateritic ores in Indonesia as an alternative to the conventionally made Fe-Ni steels. This study aims to determine the effect of cold rolling and austempering processes on the corrosion properties of the alloy. The cold-rolling reductions used are 30% and 70%, followed by an austempering process at 400°C for 30 mins with air cooling. The corrosion test was performed on four different samples-- First, a before deformation sample. Second, 30% and 70% cold-rolled samples. Third, austempered without deformation samples. Besides, fourth, deformed austempered samples. The corrosion test method implemented was the CASS Method for 2, 4, and 6 days. The highest corrosion rate obtained by 30% cold rolling, and the corrosion rate is increased as the austempering addition. The microstructures of rust are approximately porous few compact, near to voluminous coarse-grain corrosion products, and tend to crack.

scholarly journals Effects of Surface Roughness on the Electrochemical Properties and Galvanic Corrosion Behavior of CFRP and SPCC Alloy

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4211
Author(s):  
YoungHwan Kim ◽  
MyeongHan Yoo ◽  
MinSeok Moon
Keyword(s):  
Surface Roughness ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Surface Composition ◽  
Galvanic Corrosion ◽  
Reinforced Plastic ◽  
Electrode Cell ◽  
Before And After ◽  
Compositional Changes

This study investigated the potentiodynamic corrosion behavior of carbon fiber reinforced plastic (CFRP) and automotive rolled mild steel alloy (SPCC alloy) under different surface roughness conditions. Electrochemical characterization was performed using a potentiodynamic corrosion test with 5.0 wt.% NaCl aqueous solution at 25 ± 2 °C, while microstructural and compositional changes before and after corrosion were evaluated using field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS), respectively. The CFRP and SPCC corrosion rate increased as surface roughness increased. Generally, SPCC corroded faster than CFRP. The surface composition of CFRP was not affected by corrosion, regardless of the surface roughness conditions. Conversely, SPCC exhibited remarkable changes due to the formation of oxides, and its corrosion was more severe than that of CFRP as surface roughness increased. We used a double flat electrode cell to conduct a galvanic corrosion test in this study at 25 ± 2 °C. In this galvanic corrosion test, we studied different kinds of surface roughness for SPCC specimens under the CFRP material in its as-received condition and #200 condition. We confirmed that the results of galvanic corrosion for this study have a difference in corrosion amount and corrosion rate of SPCC specimens according to the surface roughness of CFRP.

Corrosion Behavior of Galvanized Steel for Porcelain Insulator’s Pin in HVAC Transmission Line

2019 ◽  
Vol 803 ◽  
pp. 45-49 ◽  
Author(s):  
Thet Htet Naing ◽  
Somjai Janudom ◽  
Vishnu Rachpech ◽  
Narisara Mahathaninwonga ◽  
Somkid Thiwong
Keyword(s):  
Corrosion Rate ◽  
Transmission Line ◽  
Corrosion Behavior ◽  
Pore Solution ◽  
Zinc Coating ◽  
Optical Microscope ◽  
Visual Observation ◽  
Passive Layer ◽  
Galvanized Steel ◽  
Corrosive Media

The corrosion behavior of galvanized steel in corrosive media of simulated concrete pore solution (SPS) with and without NaCl has been studied for applying it to porcelain insulator’s pins in high-voltage alternating current (HVAC) transmission line. It was found that zinc coating of galvanized steel was corroded increasingly for the first 3 days corrosion test in SPS mixed with NaCl solution. After that the passive layer was formed on the surface of galvanized coating and consequently, the corrosion rate was dramatically decreased nearly five times of initial corrosion rate after 21 days. In this experiment, the investigations have been performed by SEM, optical microscope and visual observation. The results show that this compact and well adherence passive layer can be effectively hindered the corrosion process.

Role of Aluminium on the Microstructure and Corrosion Behaviour of Magnesium Prepared by Powder Metallurgy Method

2020 ◽  
Vol 17 (3) ◽  
pp. 8206-8213
Author(s):  
J. Alias
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Optical Microscope ◽  
High Reactivity ◽  
Aluminium Content ◽  
Powder Metallurgy Method ◽  
X Ray Diffraction ◽  
Promising Development

Much research on magnesium (Mg) emphasises creating good corrosion resistance of magnesium, due to its high reactivity in most environments. In this study, powder metallurgy (PM) technique is used to produce Mg samples with a variation of aluminium (Al) composition. The effect of aluminium composition on the microstructure development, including the phase analysis was characterised by optical microscope (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The mechanical property of Mg sample was performed through Vickers microhardness. The results showed that the addition of aluminium in the synthesised Mg sample formed distribution of Al-rich phases of Mg17Al12, with 50 wt.% of aluminium content in the Mg sample exhibited larger fraction and distribution of Al-rich phases as compared to the 20 wt.% and 10 wt.% of aluminium content. The microhardness values were also increased at 20 wt.% and 50 wt.% of aluminium content, comparable to the standard microhardness value of the annealed Mg. A similar trend in corrosion resistance of the Mg immersed in 3.5 wt.% NaCl solution was observed. The corrosion behaviour was evaluated based on potentiodynamic polarisation behaviour. The corrosion current density, icorr, is observed to decrease with the increase of Al composition in the Mg sample, corresponding to the increase in corrosion resistance due to the formation of aluminium oxide layer on the Al-rich surface that acted as the corrosion barrier. Overall, the inclusion of aluminium in this study demonstrates the promising development of high corrosion resistant Mg alloys.

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.

Microstructures and Properties of Ti-Nb Alloys Produced by Powder Metallurgy

2011 ◽  
Vol 80-81 ◽  
pp. 431-435 ◽  
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
H. Yang ◽  
S.Y. Gu ◽  
Y.J. Yan
Keyword(s):  
Powder Metallurgy ◽  
Testing Machine ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Sintered Alloy ◽  
Xrd Diffraction ◽  
Β Phase ◽  
Ω Phase ◽  
Nb Content ◽  
And Storage

Ti-Nb alloys were prepared by powder metallurgy. Their microstructures are detected by the XRD diffraction and are observed using an optical microscope. The mechanical properties are tested using a dynamic mechanical analysis (DMA) Q800 from TA Instruments in single cantilever mode and using a 100 KN MTS testing machine with control software. It has been found that the sintered Ti-Nb alloys possess the stable α and β phases and the amount in β phase increases with increasing Nb content. The water quenched Ti-35.4Nb alloy contains α,,and βM. The as-sintered alloy has higher yield stress and storage modulus than the water quenched Ti-35.4Nb alloy, which is resulted from the α phase with high modulus in the as-sintered alloy. The ω phase can be precipitated from βMwhen the water quenched Ti-35.4Nb alloy is aged at 300 °C, causing the modulus to increase since ω phase has large modulus.

Determination of Intrinsic Magnetic Parameters of SmCo5 Phase in Sintered Samples

2005 ◽  
Vol 498-499 ◽  
pp. 129-133 ◽  
Author(s):  
Marcos Flavio de Campos ◽  
Fernando José Gomes Landgraf
Keyword(s):  
Powder Metallurgy ◽  
Domain Wall ◽  
Kerr Effect ◽  
Critical Diameter ◽  
Optical Microscope ◽  
Domain Theory ◽  
Magnetic Domains ◽  
Magnetic Parameters ◽  
Intrinsic Parameters

SmCo5 magnets are usually produced by powder metallurgy route, including milling, compaction and orientation under magnetic field, sintering and heat treatment. The samples produced by powder metallurgy, with grain size around 10 μm, are ideal for determination of intrinsic parameters. The first step for determination of intrinsic magnetic parameters is obtaining images of domain structure in demagnetized samples. In the present study, the domain images were produced by means of Kerr effect, in a optical microscope. After the test of several etchings, Nital appears as the most appropriate for observation of magnetic domains by Kerr effect. Applying Stereology and Domain Theory, several intrinsic parameters of SmCo5 phase were determined: domain wall energy 120 erg/cm2, critical diameter for single domain particle size 2 μm and domain wall thickness 60 Å. In the case of SmCo5, and also other phases with high magnetocrystalline anisotropy, Domain Theory presents several advantages when compared with Micromagnetics.

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