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Enhancing ductility of sintered Fe-Ni-Mo-Mn-Si-C alloy by Co addition
(2024-05-17)
Putsaccada, Viseth
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Wongsa-Ngam, Jittraporn
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Ohtake, Naoto
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Morakotjinda, Monnapas
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Krataithong, Rungtip
This research aims to investigate the effect of cobalt (Co) on accelerating the bainitic transformation in sintered Fe-Ni-Mo-Mn-Si-C alloys. Experimental sintered specimens were prepared from the mixtures of pre-alloyed Fe-4.00Ni-0.50Mo-0.2Mn powder with a fixed 4.00 wt% silicon carbide and varied Co contents (0.50 to 3.00 wt%) using a traditional press and sinter process. Sintering was conducted in a vacuum furnace at 1250 °C for 45 minutes and under slow cooling in the sintering furnace. It was found that Co strongly influenced the kinetics of bainite transformation in sintered Fe-Ni-Mo-Si-C-(Co) alloys. Tensile strength and hardness of sintered alloys increased with Co content. High elongation values were obtained in sintered specimens with high Co contents. The increases of tensile strength and ductility with Co content were attributed to accelerated bainitic ferrite formation and retained austenite stability, respectively.
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Characterization of biodiesel and soot contamination on four-ball wear mechanisms using electron microscopy and confocal laser scanning microscopy
(2020-10-15)
Oungpakornkaew, Pitchaporn
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Karin, Preechar
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Tongsri, Ruangdaj
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Hanamura, Katsunori
Utilization of biodiesel as an alternative fuel has been increasing nowadays in term of quantity and ratio of bio-resource derived esters from B7 to B100. The tribological characteristic due to biodiesel application has been more interesting. Not only fuel dilution but also soot contamination in engine oil must be taken into account for the effect to the engine wear. This research employed carbon black as soot model and B7, B20 and B100 as contaminated fuel. Two blended grades of diesel engine oils (API CI-4 and CK4) were tested by a four-ball wear tester. Scanning electron microscopy (SEM) was used to investigate the wear characteristic. Three-dimensional images of wear scars and surface roughness were observed from confocal microscopy technique. The result shows that CK-4 has greater anti-wear performance and can maintain the lubricating performance when the oil is contaminated. For CI-4 cases, soot contamination causes increasing wear, but biodiesel fuel dilution shows wear reduction.
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Influence of Soot Contamination in API CI-4 Engine Oil on Four-Ball Metallic Wear Using Electron Microscopy Image Analysis
(2020-07-27)
Oungpakornkaew, Pitchaporn
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Rungsritanapaisan, Panyakorn
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Karin, Preechar
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Tongsri, Ruangdaj
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Tanprayoon, Dhritti
Engine lubricant has an important role in decreasing friction and the wearing of moving parts in the engine. However, soot contaminated in engine oil could change chemical and physical properties that affect the lubricant oil operation. Soot particles were simulated using carbon black in order to eliminate the effect of metallic ash and unburned hydrocarbon, which contained in particulate matter. The carbon black was blended in CI-4 lubricating oil. The investigation of metallic wear was associated with the use of a four-ball wear test. The amount of wear was compared by measuring the wear scar diameter of the worn surface on the steel balls. Scanning electron microscope (SEM) and confocal laser scanning microscopy were used for characterizing wear scar and surface roughness, respectively. In addition, the evidence of lubricant additive elements was detected on the wear surface by Energy Dispersive X-ray analysis (EDX). This research found that engine oil with soot contamination could lead to increasing amounts of abrasive wear by 83% and has approximately 1.1% larger wear scar diameter.
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Dry-sliding wear of the 316L/h-BN composites produced under crack ammonia atmosphere
(2020-01-01)
Chusong, Ekkarat
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Kansuwan, Panya
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Ohtake, Naoto
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Wila, Pongsak
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Tosangthum, Nattaya
Wear is one of different problems in mechanical failures of moving components. When a component encounters friction force on its surface, crack initiation tends to occur and wear follows crack propagation. Thus, the moving parts of automobiles should have proper wear resistance for long-time services, in addition to having high strength and hardness for heavy load operation. A self-lubricating material with compromised tribological and mechanical properties is important for some moving components. In this work, self-lubricating composites, metal matrix composites embedded with a solid lubricant, made from 316L stainless steel powder mixed with different hexagonal boron nitride (h-BN) contents of 10%, 15% and 20% by volume. The mixed powders were compacted into green parts (according with MPIF Standard 42) with density of 6.5 g·cm<sup>-3</sup>. Then, the green parts were sintered at 1100, 1150, 1200, 1250 and 1300°C under cracked ammonia (75% H<inf>2</inf>+25% N<inf>2</inf>) atmosphere for 60 min. The experimental results revealed that increases of hardness and strength sintered 316L matrix by reduction of pore amount and size were due to the increase of sintering temperature. However, the increase of h-BN content resulted in increase of pore amount and size. Additions of h-BN content up to 20 vol. % reduced friction coefficient of the sintered composites. At sintering temperatures of equal to and higher than 1200°C, h-BN did not react with 316L stainless steel powders to form intergranular boride phase. The sintered composites produced under the maximum experimental sintering temperature of 1300°C showed low specific wear rate.
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Impact of Soot and Engine Oil Additive Characteristics on Metallic Wear using Electron Microscopy and Confocal Microscopy
(2020-01-01)
Rungsritanapaisan, Panyakorn
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Karin, Preechar
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Amornprapa, Warawut
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Tanprayoon, Dhritti
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Tongsri, Ruangdaj
Soot particles are produced inside the combustion chamber of the internal combustion engines and will later be exhausted into the thermosphere. Part of these particles will contaminate the engine oil. When this happens, diesel engine abrasion or, in a worst-case scenario, lubricant starvation will occur. This circumstance will eventually cause engine wear. This research uses X-Ray Fluorescence (XRF) technique to analyze the additive element in engine oil. For wear test, this research uses tribology Four ball wear tester to substitute point contact wear mechanism. Then the worn surface is analyzed with Scanning Electron Microscope (SEM). Confocal Microscope are used to study the effect of additive on soot dispersion in engine oil, which affects the metal wear mechanism. This research use Laser Particle Size Analyzer to investigate performance of soot dispersant additive in each engine oil. The results show that, the wear scar diameters significantly increased when the American Petroleum Institute (API) CD standard engine oil is contaminated with soot. On the other hand, American Petroleum Institute (API) CF-4 standard engine oil which contains higher amount of additive has a lower roughness value, because its soot dispersant additive improves the dispersing of carbon black (CB). When the CB is dispersed, it will serve to polish the ball's surface, resulting in a lower roughness value in the CB contaminated high amount of additive engine oil, than the low amount of additive engine oil that has soot contaminating.
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Impact of oil additive characteristics on biofuel engine wear using electron microscopy and confocal microscopy
(2019-01-01)
Rungsritanapaisan, Panyakorn
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Karin, Preechar
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Tanprayoon, Dhritti
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Tongsri, Ruangdaj
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Hanamura, Katsunori
Soot particles are produced during combustion process in the diesel engine. These particles will later exhaust into the thermosphere and part of them will contaminate the engine oil. When the lubricant is contaminated with soot, diesel engine abrasion or in a worst-case scenario lubricant starvation occurs. This situation will eventually lead into engine wear. High volume of soot also raises acid level of the area. If this state co-occurs with high temperature of the engine and volatile gases during operation, engine corrosion may also be produced. This research study the effect of additive volume on the dispersion of soot in engine oil and effect of additive on size and volume of soot which affect to mechanism of wear in metal by tribology four-ball tester, image analysis by scanning electron microscope and particle size analysis by laser diffraction technique.
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Impact of engine oil's additives on particulate matter's micro-and nanostructure using electron microscopy image analysis
(2019-01-01)
Koko, Phyozin
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Karin, Preechar
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Rungsritanapaisan, Sippakorn
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Tongsri, Ruangdaj
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Hanamura, Katsunori
According to increasingly stringent emission regulations on particle emissions from automotive vehicles, a diesel engine must be equipped with diesel particulate filter (DPF) to trap the particulate matters (PMs) which can be harmful to human health. Morphology and chemical composition of particulate matters were successfully studied using electron microscopy and electron dispersive x-ray spectroscopy (EDS) analysis. Microstructure of particulate matters derived from diesel blending lubricating oil were not significant different compared to diesel PM. Nanostructure of soot is a spherical shape composed of curve line crystallites and the particle sizes were in the range of 10 -60 nm while the metal oxide ash is composed of lattice fringes. Chemical composition analysis of EDS result showed that metallic additives from lubricating oil cannot be burned during combustion and might be transformed into metal oxide ash.
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Facile synthesis and characterization of tenorite nanoparticles from gas-atomized Cu powder
(2015-01-01)
Buarod, Eumporn
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Pithakratanayothin, Sakollapath
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Naknaka, Suchuta
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Chaiyasith, Pachernchaiyapat
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Yotkaew, Thanyaporn
CuO powder is widely used because of its high activity and selectivity in oxidation/reduction reactions. CuO nanoparticles are interesting because of their high ratio of surface area to mass, which is expected to enhance the catalytic performance of a material. Because of such importance, CuO nanoparticles were prepared by two different facile routes. The first involved the reaction of pure Cu powder with nitric acid to form Cu(NO<inf>3</inf>)<inf>2</inf> intermediate. In the second route, glacial acetic acid was employed to react with pure Cu powder to form Cu(CH<inf>3</inf>COO)<inf>2</inf> intermediate. After purification, both intermediates were reacted with NaOH via a solid-state route to form CuO powders. The intermediates and end products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction technique. Experimental results indicated that synthesis of the CuO nanoparticles via the Cu(NO<inf>3</inf>)<inf>2</inf> intermediate yielded slightly higher product and fine particle sizes with a larger aspect ratio. In contrast, the Cu(CH<inf>3</inf>COO)<inf>2</inf> intermediate route yielded lower product yield and fine particle sizes with a smaller aspect ratio. However, due to the extremely fine particle size it was observed that nanoparticle agglomeration could not be avoided particularly in the CuO nanopowders produced via the Cu(CH<inf>3</inf>COO)<inf>2</inf> intermediate route.
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Sintered frictional materials based on cu powders
(2013-10-04)
Yodkeaw, Thanyaporn
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Tosangthum, Nattaya
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Krataitong, Rungtip
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Morakotjinda, Monnapas
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Prapai, Jirapat
Sintered frictional materials (SFMs) were fabricated by using powder metallurgical process. Powder formulations were experimented to investigate effects of Sn, C and ZrO<inf>2</inf> additions on mechanical and tribological properties of the sintered composites made for dry frictional materials applications. The developed SFMs consisted of non-lead friction material. Natural sand (SiO<inf>2</inf>) and ZrO<inf>2</inf> were employed instead of lead oxide to provide frictional components. Interrelationships between chemical composition, sintering temperature, friction coefficient, wear behavior and mechanical property of the SFMs have been studied. It was found that sintering temperature affected hardness property of the SFMs. The hardness was also affected by SFM compositions. Friction coefficient increased with increasing ZrO<inf>2</inf> content. Addition of natural sand resulted in decrease of the hardness of the SFMs. Graphite also affected hardness and friction coefficient of SFMs containing no sand. Employing prealloyed Cu-Sn powders provided SFMs with better mechanical properties compared to the SFMs made of admixed Cu and Sn powders. © (2013) Trans Tech Publications, Switzerland.
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Effects of sintering time and atmosphere on mechanical properties of injection molded Tungsten alloy
(2013-01-01)
Lamlerttham, Jittrabhanu
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Wila, Pongsak
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Morakotjinda, Monnapas
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Krataitong, Rungtip
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Vetayanukul, Bhanu
Tungsten is a promising refractory metal suitable for applications in which wear resistance, thermal stability and high weight are needed. In this work, the tungsten feedstock (94wt%W with balance of Ni-Cu-Co alloy) was used to form tensile test specimens by using metal injection molding (MIM) process. The molded specimens were debinded by catalytic debinding technique to convert to the brown specimens. After debinding, the brown parts were sintered under vacuum atmosphere (10<sup>-5</sup> bar) with varied sintering times at sintering temperature from 1350 to 1450°C. The specimens sintered at 1450°C for 3 hours provided optimum sintered density and mechanical properties. The results showed that mechanical properties of the specimens sintered at 1450°C dramatically decreased when sintering times were longer than 3 hours. The specimens sintered at 1450°C for 8 hours showed brittleness. Physically, inferior mechanical properties were attributed to wettability and porosity of the binder phase. Chemical analyses were performed with the sintered W-(Ni-Cu-Co) specimens by using energy dispersive spectroscopy with mode of quantitative analysis. The specimens sintered at 1400°C for 3 hours showed high W content (28.95 wt. %) dissolved in the Ni-Cu-Co binder. However, penetration of the liquid binder was incomplete. The specimens sintered at 1450°C for 3 hours showed higher W content (34.28 wt. %) dissolved in the Ni-Cu-Co binder (with lower Cu content). Distribution of Cu was uniform across the whole specimen. Wetting of the liquid binder on W grains was complete without porosity. The specimens sintered at 1450°C for longer than 3 hours showed less W content (< 28.95 wt. %) dissolved in the Cu-depleted Ni-Co binder. Porosity was observed in the binder phase and in W grains. Sintering between W grains was also observed. Effects of different sintering atmospheres were also investigated. It was found that increasing the sintering chamber pressure caused detrimental effects on both physical and mechanical properties of the sintered tungsten specimens. In addition, nitrogen atmosphere gave similar results to those for increased chamber pressure. © (2013) Trans Tech Publications.

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