Displaying publications 41 - 60 of 102 in total

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  1. Fatmahardi I, Mustapha M, Ahmad A, Derman MN, Lenggo Ginta T, Taufiqurrahman I
    Materials (Basel), 2021 Apr 30;14(9).
    PMID: 33946335 DOI: 10.3390/ma14092336
    Resistance spot welding (RSW) is one of the most effective welding methods for titanium alloys, in particular Ti-6Al-4V. Ti-6Al-4V is one of the most used materials with its good ductility, high strength, weldability, corrosion resistance, and heat resistance. RSW and Ti-6Al-4V materials are often widely used in industrial manufacturing, particularly in automotive and aerospace industries. To understand the phenomenon of resistance spot weld quality, the physical and mechanical properties of Ti-6Al-4V spot weld are essential to be analyzed. In this study, an experiment was conducted using the Taguchi L9 method to find out the optimum level of the weld joint strength. The given optimum level sample was analyzed to study the most significant affecting RSW parameter, the failure mode, the weld nugget microstructure, and hardness values. The high heat input significantly affect the weld nugget temperature to reach and beyond the β-transus temperature. It led to an increase in the weld nugget diameter and the indentation depth. The expulsion appeared in the high heat input and decreased the weld nugget strength. It was caused by the molten material ejection in the fusion zone. The combination of high heat input and rapid air cooling at room temperature generated a martensite microstructure in the fusion zone. It increased the hardness, strength, and brittleness but decreased the ductility.
    Matched MeSH terms: Corrosion
  2. Joseph Sahaya Anand, T., Sivarao, Ganesh Kumar, K.
    MyJurnal
    Ni3A1 is an intermetallic compound which has unique property with temperature. Annealing is done at temperature 300, 500, and 700°C for 1 hour and analyzed with X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX) analysis for their crystallographic nature. EDX confirmed the composition of Ni3A1 with exact stoichiometry, whereas the XRD confirmed the crystallographic nature of the material. The mechanical properties by hardness results showed that Ni3A1 has highest Vickers hardness value of 554 HV when it is non-heat treated. Its hardness drops as it undergoes annealing process. Corrosion analysis by tafel test shows that its polarization resistance may increase up to 4145 W cm2 when annealed at high temperature. These results show that Ni3A1 is a promising material to be considered as an alternative automotive body.
    Matched MeSH terms: Corrosion
  3. Zaifol Samsu, Mohd Harun, Mahdi E. Mahmoud, Norasiah Ab Kasim, Katrul Hisham Alahudin, Zaiton Selamat
    MyJurnal
    An air fin cooler system consists of a tube bundle that is used to cool the various processing fluids in process industries that utilizes air as a cooling medium. The said tubes failed when exposed to corrosive environment(s). Tubes located at the bottom row of the air fin cooler were corroded as a result of exposure to rain water, brought in by induced air when the wind blows. The tube material is A179 Carbon steel. Two tubes, namely Tube A and Tube B along with an aluminum fin in each tube were investigated. A leak was observed on tube A, probably due to Corrosion Under Deposit mechanism. A general corrosion attack was observed at tube B, and macroscopic analysis showed that the corrosion occurred along the grain boundaries, which consist of ferrite and pearlite. Microanalysis showed that the corrosion product on the outer surface of the tube consists of Fe, O, S and Cl elements. It is concluded that the humid environment contains corrosive elements such as S and Cl. EDAX analysis on the fin showed that the material is pure aluminum. However, the aluminum was corroded by galvanized corrosion and produced brittle Al2O3 as a result.
    Matched MeSH terms: Corrosion
  4. Zaifol Samsu, Muhamad Daud, Siti Radiah Mohd Kamarudin, Nur Ubaidah Saidin, Abdul Aziz Mohamed, Mohd Sa’ari Ripin, et al.
    MyJurnal
    Boundary element method (BEM) is a numerical technique that used for modeling infinite domain as is the case for galvanic corrosion analysis. The use of boundary element analysis system (BEASY) has allowed cathodic protection (CP) interference to be assessed in terms of the normal current density, which is directly proportional to the corrosion rate. This paper was present the analysis of the galvanic corrosion between Aluminium and Carbon Steel in natural sea water. The result of experimental was validated with computer simulation like BEASY program. Finally, it can conclude that the BEASY software is a very helpful tool for
    future planning before installing any structure, where it gives the possible CP interference on any nearby unprotected metallic structure.
    Matched MeSH terms: Corrosion
  5. Daud, M., Mohd Kamarudin, S.R., Samsu, Z., Ripin, M.S., Sattar, M.S., Rejab, R.
    MyJurnal
    The corrosion behaviour of ternary aluminium alloy sacrificial anodes with small amount addition of tin as depassivating element in natural seawater was studied by means of conventional DC electrochemical measurements. Metallurgical microscope was employed in order to observe the changing of microstructure caused by tin present in ternary alloys. The relationship between microstructure and electrochemical results was examined and particular attention paid to the cause of the electrochemical efficiency of anode performance. The results indicate that the proper precipitates uniformly distributed of tin are influence on improving electrochemical performance of alumnium alloy anode.
    Matched MeSH terms: Corrosion
  6. Junaidah Jai, Wan Shabuddin Wan Ali
    Scientific Research Journal, 2011;8(2):49-70.
    MyJurnal
    Aluminium (Al) is a low cost, lightweight and corrosion resistant material, which corrodes when exposed to pitting agents. Palm olein exhibits characteristics, which indicate its suitability as a corrosion inhibitor. Tween 20, hexane and diethyl triamine were used as additives to Palm olein to form the inhibitor formulation POT2OHA. The inhibition efficiency (IE) and behaviour of the POT2OHA were determined using potentiodynamic polarization in which Al 6061 samples were immersed in a 1 M HC1 solution at 26, 50 and 70 °C in the presence of different POT2OHA concentrations: 0, 0.03, 0.07, 0.10, 0.13 and 0.17 M The IE increased with increasing POT2OHA concentration, but decreased with increasing temperature. The work presented indicates that POT2OHA is a mixed-type inhibitor capable of inhibiting both corrosive anodic and cathodic reactions. According to the Langmuir isotherm results POT2OHA adsorbs on the A16061 surface through semiphys iosorption and/or semi-chemisorption. The POT2OHA adsorption mechanism on Al 6061 takes through the protonation of micelles by the HC1 solution, whereby protonated micelles in the presence of chloride ions adsorb on both cathodic and anodic surface corrosion sites.
    Matched MeSH terms: Corrosion
  7. Nik Rozlin Nik Masdek, Wan Muhammad Aniq Aiman, Mardziah Che Murad, Zuraidah Salleh, Koay Mei Hyie
    MyJurnal
    In the electrodeposition system, adding saccharin alters the properties of the metal deposits by changing the electrode kinetics of the deposited surface. In this study, nanocrystalline cobalt-iron (CoFe) coating was synthesised using the electrodeposition technique with different saccharin concentrations. The results obtained showed that the coating thickness increased while the grain size decreased from 51 nm to 40 nm when the saccharin concentration increased from 0 to 2 g/L. The nanocrystalline CoFe coating produced with 2 g/L of saccharin concentration resulted in the smallest particle size of 71.22 nm and the highest microhardness of 251.86 HV. From the salt spray test (24 and 48 hours) it was found that the use of saccharin at higher concentration of 2 g/L improves the corrosion resistance of the nanocrystalline CoFe coating significantly due to the change of surface morphology as well as the decrease in grain size.
    Matched MeSH terms: Corrosion
  8. Asri RIM, Harun WSW, Samykano M, Lah NAC, Ghani SAC, Tarlochan F, et al.
    Mater Sci Eng C Mater Biol Appl, 2017 Aug 01;77:1261-1274.
    PMID: 28532004 DOI: 10.1016/j.msec.2017.04.102
    Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys. This article also takes a close look at the effect of corrosion towards the implant and human body and the mechanism to improve it. Due to this corrosion delinquent, several surface modification techniques have been used to improve the corrosion behavior of biocompatible metals such as deposition of the coating, development of passivation oxide layer and ion beam surface modification. Apart from that, surface texturing methods such as plasma spraying, chemical etching, blasting, electropolishing, and laser treatment which used to improve corrosion behavior are also discussed in detail. Introduction of surface modifications to biocompatible metals is considered as a "best solution" so far to enhanced corrosion resistance performance; besides achieving superior biocompatibility and promoting osseointegration of biocompatible metals and alloys.
    Matched MeSH terms: Corrosion
  9. Ibrahim, R.E., Talari, M.K., Sabrina, M. Yahaya, Rosmamuhamadani, R., Sulaiman, S., Ismail, M.I.S.
    MyJurnal
    The aluminium-silicon (Al-Si) based on Metal Matrix Composites (MMCs) is widely used in lightweight
    constructions and transport applications requiring a combination of high strength and ductility. A grain
    refinement plays a crucial role in improving characteristics and properties of Al alloys. In this investigation,
    titanium diboride (TiB2) and scandium (Sc) inoculants were added to the Al-Si alloys for grain refinement of
    an alloy. In this investigation, the corrosion resistance rate of Al-Si cast alloy reinforced by TiB2 and Sc were
    measured by potentiostat (AUTOLAB) instrument. The aim of this research is to investigate the corrosion
    rate for Al-Si-TiB2-Sc composites that immersed in different concentration of acidic solutions. Besides, the
    immersion time of acidic solutions also was investigated. All the samples were prepared accordingly for
    ASTM standard by the composition of 6.0 wt% TiB2 and 0.6wt% Sc. All the samples undergo cold mounting
    technique for easy handling on corrosion tests. Then the samples were immersed in two different
    concentrations acidic medium solutions, which were 0.1.and 1.0 M hydrochloric acids (HCl). The corrosion
    rate also was investigated for immersion samples of 1.0 M HCl for 21 days. From the results obtained, added
    TiB2 and Sc onto Al-Si alloy gave the better properties in corrosion resistance. Corrosion rates to reduce when
    the samples were immersed in a lower concentration of acidic medium, 0.1 HCl. However, there are some
    significant on the result but it still following the corrosion rates trend. Thus, improvements to reinforcement
    content need to be done in further research to cover the lack of this corrosion rates trend.
    Matched MeSH terms: Corrosion
  10. Sim BM, Hong TS, Hanim MA, Tchan EN, Talari MK
    Materials (Basel), 2019 Oct 10;12(20).
    PMID: 31658593 DOI: 10.3390/ma12203285
    Duplex stainless steels (DSSs) are complex materials and they have been widely used in the marine environment and gas industries, primarily offering a better resistance of pitting corrosion and good mechanical properties. In the present work, the effects of heat treatment on duplex stainless steel (DSS) weld overlay samples that were heat treated at three different temperatures, namely 350 °C, 650 °C, and 1050 °C, and followed by air cooling and water quenching were studied. Stress relief temperature at 650 °C had induced sigma phase precipitation in between delta ferrite and austenite (δ/γ) grain boundaries, resulting in the loss of corrosion resistance in the weld metal. Interestingly, post weld heat treatment (PWHT) test samples that were reheated to solution annealing temperature had shown no weight loss. The ferrite count determination in the region of weld metal overlay increased at hydrogen relief and decreased at stress relief temperatures due to slow cooling, which is more favorable to austenite formation. The amount of ferrite in the weld metals was significantly reduced with the increment of solution anneal temperature to 1050 °C because of sufficient time for the formation of austenite and giving optimum equilibrium fraction in the welds.
    Matched MeSH terms: Corrosion
  11. Fathul Karim Sahrani, Zaharah Ibrahim, Madzlan Aziz, Adibah Yahya
    Corrosion caused by sulphate-reducing bacteria (SRB) isolated from seawater nearby to Pasir Gudang has been studied. The test coupon was a AISI 304 stainless steel. Potential and corrosion rate measurements were carried out in various types of culturing solutions, with SRB1, SRB2, combination of SRB1 & SRB2 and without SRBs inoculated (sterilized). From Tafel plots a higher corrosion rate has been found in medium inoculated with SRBs than that of the sterilized medium (control). When SRBs were present in the medium, the Tafel plot shifted towards more negative values (Ecorr was shifted to much less anodic values) and increase in current density compared to that of the sterilized medium (control). Localized corrosion was observed on the metal surface, and it was associated to the SRB activity. X-ray analysis (EDAX) showed that the corrosion product has higher content of sulphur for medium containing SRBs than that of the sterilized medium. X-Ray Diffraction analysis carried out on corrosion products which showed the presence of iron sulphide. This indicates the influence of the presence of SRB in corrosion process.
    Matched MeSH terms: Corrosion
  12. Husniyati Roslan, Fatanah M. Suhaimi, Zawiah Musa, Nizuwan Azman, Nur Jihan Mohd Zukhi
    MyJurnal
    Sterilisation is an essential step in the reprocessing of reusable dental instruments including burs that have become contaminated, or potentially contaminated. Transmission of disease or infection may happen as an effect of improper sterilisation of the reused instruments. Dental burs are one of the essential tools in any conservative dental procedures, which undergo multiple sterilisation cycles before being discarded. However, repeated sterilisation process is associated with the reduction in cutting efficiency of a bur that is potentially due to corrosion. Thus, this study aims to compare the effect of two sterilisation methods on cutting efficiency of a diamond bur that is commonly used in dental procedures. Methods: 30 fissure diamond burs were randomly divided into three sterilisation groups: Group A (dry heat), B (steam under pressure) and C (control). Each bur was used to cut teeth for 45 seconds for ten cycles. Between cuts, the burs underwent sterilisation based on their sterilisation groups. Amount of cutting weight was measured after each cut. Results: This study shows that no significant difference (p>0.05) in the cutting efficiency of the burs following sterilisation of Groups A and B. However, there is a significant mean difference (p
    Matched MeSH terms: Corrosion
  13. Solhan Yahya, Afidah Abdul Rahim, Affaizza Mohd Shah, Rohana Adnan
    Anticorrosion potential of mangrove tannins on aluminium alloys AA6061 in NaCl solution has been studied using potentiodynamic polarisation method and scanning electron microscopy (SEM). The study was carried out in different pH of corrosive medium in the absence and presence of various concentrations of tannin. The corrosion inhibition behaviour of the mangrove tannin on AA6061 aluminium alloy corrosion was found to be dependant on the pH of NaCl solution. Our results showed that the inhibition efficiency increased with increasing tannins concentration in chloride solution at pH 6. Treatment of aluminium alloy 6061 with all concentrations of mangrove tannins reduced the current density, thus decreased the corrosion rate. Tannins behaved as mixed inhibitors at pH 6 and reduction in current density predominantly affected in cathodic reaction. Meanwhile, at pH 12, addition of tannins shifted the corrosion potential to more cathodic potentials and a passivating effect was observed in anodic potentials. SEM studies have shown that the addition of tannins in chloride solution at pH 12 reduced the surface degradation and the formation of pits.
    Matched MeSH terms: Corrosion
  14. Fathul Karim Sahrani, Zaharah Ibrahim, Adibah Yahya, Madzlan Aziz
    Sulphate-reducing bacteria (SRB), implicated in microbiologically influenced corrosion were isolated from the deep subsurface at the vicinity of Pasir Gudang, Johor, Malaysia. Electrochemical impedance spectroscopic (EIS) study was carried out to determine the polarization resistance in various types of culturing solutions, with SRB1, SRB2, combination of SRB1 and SRB2 and without SRBs inoculated (control). EIS results showed that in the presence of SRB1, SRB2 and mixed culture SRB1 and SRB2, polarisation resistance values were 7170, 6370 and 7190 ohms respectively compared to that of control, 92400 ohm. X-ray analysis (EDS) of the specimens indicated high sulphur content in the medium containing SRBs. Localized corrosion was observed on the metal surface which was associated with the SRB activity.
    Matched MeSH terms: Corrosion
  15. Abdurrahman J, Wahyuningrum D, Achmad S, Bundjali B
    Corrosion is one of the major problems in petroleum mining and processing industry. The pipelines used to transport crude oil from reservoir to the processing installation were made from carbon steel that is susceptible towards corrosion. One of the best methods to prevent corrosion that occurred at the inner parts of carbon steel pipelines is to use organic corrosion inhibitor. One of the potent organic corrosion inhibitors is amino acids derivatives. In this study, dipeptide compound namely benzoylalanylglycine methyl ester and benzoylalanylglycine have been synthesized. The structure elucidation of the products was performed by IR, MS and NMR spectroscopy. The determination of corrosion inhibition activity utilized the Tafel method. The corrosion inhibition efficiency of glycine methyl ester, benzoylalanine, dipeptide benzoylalanylglycine methyl ester and dipeptide benzoylalanylglycine were 63.34%, 35.86%, 68.40% and 27.72%, respectively. These results showed that the formation of dipeptide benzoylalanylglycine methyl ester, derived from carboxylic protected glycine and amine protected alanine, increased the corrosion inhibition activity due to the loss of acidity center in the structure of glicine and L-alanine that would induce the corrosive environment towards carbon steel.
    Matched MeSH terms: Corrosion
  16. Raza MR, Sherazi I, Muhammad Aslam, Ahmad F, Abu Bakar Sulong, Muhamad Norhamidi, et al.
    Sains Malaysiana, 2017;46:285-293.
    316L stainless steel is a common biomedical material. Currently, biomedical parts are produced through powder injection molding (PIM). Carbon control is the most critical in PIM. Improper debinding can significantly change the properties of the final product. In this work, thermal debinding and sintering were performed in two different furnaces (i.e. laboratory and commercially available furnaces) to study the mechanical properties and corrosion resistance. Debounded samples were sintered in different atmospheres. The samples sintered in inert gas showed enhanced mechanical properties compared with wrought 316L stainless steel and higher corrosion rate than those sintered in the vacuum furnace. The densification and tensile strength of the hydrogen sintered samples increased up to 3% and 51%, respectively, compared with those of the vacuum-sintered samples. However, the samples sintered in inert gas also exhibited reduced ductility and corrosion resistance. This finding is attributed to the presence of residual carbon in debonded samples during debinding.
    Matched MeSH terms: Corrosion
  17. Al-Amiery AA, Kadhum AAH, Mohamad AB, Junaedi S
    Materials (Basel), 2013 Apr 02;6(4):1420-1431.
    PMID: 28809218 DOI: 10.3390/ma6041420
    2-(1-methyl-4-((E)-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene)-hydrazineecarbothioamide (HCB) was synthesized as a corrosion inhibitor from the reaction of 4-aminoantipyrine, thiosemicarbazide and 2-methylbenzaldehyde. The corrosion inhibitory effects of HCB on mild steel in 1.0 M HCl were investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed that HCB inhibited mild steel corrosion in acidic solution and inhibition efficiency increased with an increase in the concentration of the inhibitor. The inhibition efficiency was up to 96.5% at 5.0 mM. Changes in the impedance parameters suggested that HCB adsorbed on the surface of mild steel, leading to the formation of a protective film. The novel corrosion inhibitor synthesized in the present study was characterized using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectral data.
    Matched MeSH terms: Corrosion
  18. Karunarathne VK, Paul SC, Šavija B
    Materials (Basel), 2019 Aug 17;12(16).
    PMID: 31426501 DOI: 10.3390/ma12162622
    In this study, the use of nano-silica (nano-SiO2) and bentonite as mortar additives for combating reinforcement corrosion is reported. More specifically, these materials were used as additives in ordinary Portland cement (OPC)/fly ash blended mortars in different amounts. The effects of nano-silica and bentonite addition on compressive strength of mortars at different ages was tested. Accelerated corrosion testing was used to assess the corrosion resistance of reinforced mortar specimens containing different amounts of nano-silica and bentonite. It was found that the specimens containing nano-SiO2 not only had higher compressive strength, but also showed lower steel mass loss due to corrosion compared to reference specimens. However, this was accompanied by a small reduction in workability (for a constant water to binder ratio). Mortar mixtures with 4% of nano-silica were found to have optimal performance in terms of compressive strength and corrosion resistance. Control specimens (OPC/fly ash mortars without any additives) showed low early age strength and low corrosion resistance compared to specimens containing nano-SiO2 and bentonite. In addition, samples from selected mixtures were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Finally, the influence of Ca/Si ratio of the calcium silicate hydrate (C-S-H) in different specimens on the compressive strength is discussed. In general, the study showed that the addition of nano-silica (and to a lesser extent bentonite) can result in higher strength and corrosion resistance compared to control specimens. Furthermore, the addition of nano-SiO2 can be used to offset the negative effect of fly ash on early age strength development.
    Matched MeSH terms: Corrosion
  19. Akrima Abu Bakar, Muhammad Khairool Fahmy Mohd Ali, Norhazilan Md. Noor, Nordin Yahaya, Mardhiah Ismail, Ahmad Safuan A. Rashid
    Sains Malaysiana, 2017;46:1323-1331.
    Baram Delta Operation had been producing oil and gas since 1960's and serious pipelines failure was reported in the year of 2005. The final investigation has concluded that one of the species of bacteria that has been identified to cause microbiologically influenced corrosion, specifically known as sulfate reducing bacteria (SRB) was found to be one of the potential contributing factors to the incidents. This work investigates the potential use of ultraviolet (UV) radiation to inhibit the SRB consortium that was cultivated from the crude oil in one of the main trunk lines at Baram Delta Operation, Sarawak, Malaysia. The impact of UV exposure to bio-corrosion conditions on carbon steel coupon in certain samples for 28 days was discussed in this study. The samples were exposed to UV radiation based on variations of parameters, namely: time of UV exposure; and power of UV lamp. The significant changes on the amount of turbidity reading and metal loss of the steel coupon were recorded before and after experiment. The results showed that SRB growth has reduced rapidly for almost 90% after the UV exposure for both parameters as compared to the abiotic samples. Metal loss values were also decreased in certain exposure condition. Additionally, field emission scanning electron microscopy (FESEM) coupled with energy dispersive spectroscopy (EDS) was performed to observe the biofilm layer formed on the metal surface after its exposure to SRB. The evidence suggested that the efficiency of UV treatment against SRB growth could be influenced by the particular factors studied
    Matched MeSH terms: Corrosion
  20. Wu H, Kong XY, Wen X, Chai SP, Lovell EC, Tang J, et al.
    Angew Chem Int Ed Engl, 2021 Apr 06;60(15):8455-8459.
    PMID: 33368920 DOI: 10.1002/anie.202015735
    Improving the stability of cuprous oxide (Cu2 O) is imperative to its practical applications in artificial photosynthesis. In this work, Cu2 O nanowires are encapsulated by metal-organic frameworks (MOFs) of Cu3 (BTC)2 (BTC=1,3,5-benzene tricarboxylate) using a surfactant-free method. Such MOFs not only suppress the water vapor-induced corrosion of Cu2 O but also facilitate charge separation and CO2 uptake, thus resulting in a nanocomposite representing 1.9 times improved activity and stability for selective photocatalytic CO2 reduction into CH4 under mild reaction conditions. Furthermore, direct transfer of photogenerated electrons from the conduction band of Cu2 O to the LUMO level of non-excited Cu3 (BTC)2 has been evidenced by time-resolved photoluminescence. This work proposes an effective strategy for CO2 conversion by a synergy of charge separation and CO2 adsorption, leading to the enhanced photocatalytic reaction when MOFs are integrated with metal oxide photocatalyst.
    Matched MeSH terms: Corrosion
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