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Materials Science and Engineering

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Journal of Metals, Materials and Minerals

2006

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Development Of Flame Retardant Polyphosphoric Acid Coating Based On The Polyelectrolyte Multilayers Technique, K Srikulkit, C Iamsamai, S T. Dubas Dec 2006

Development Of Flame Retardant Polyphosphoric Acid Coating Based On The Polyelectrolyte Multilayers Technique, K Srikulkit, C Iamsamai, S T. Dubas

Journal of Metals, Materials and Minerals

Polyelectrolyte multilayer (PEM) thin films were deposited on silk by sequential deposition of Chitosan and polyphosphoric acid. This PEM composition takes advantage of synergetic effect of the phosphorus and the nitrogen to provide an efficient coating, which prevents fiber decomposition at high temperature. Prior to the PEM assembly on silk fibers, the growth of the film was initially monitored using an atomic force microscopy (AFM). Films formed on silicon wafer after 10, 20, 30, 40 and 60 layers showed somewhat linear increase, which is consistent with the PEM technique. A total thickness ranging from 10 to 107 nm for the …

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Uv Radiation Energy Consumption In Curing Process Of Epoxidized Sunflower Oil-Organoclay Hybrid Coatings, N Jiratumnukul, R Intarat Dec 2006

Uv Radiation Energy Consumption In Curing Process Of Epoxidized Sunflower Oil-Organoclay Hybrid Coatings, N Jiratumnukul, R Intarat

Journal of Metals, Materials and Minerals

Epoxidized sunflower oil (ESO) can be cured with ultraviolet radiation using either cationic or hybrid initiation. The organoclay was prepared by the cationic exchange process, in which sodium ions were replaced by alkyl ammonium ions. Organoclay was incorporated into epoxidized sunflower oil UVcurable systems. The effects of diluents and types of photo initiators were studied. It was found that the formulations with a hybrid photoinitiator required less energy in the curing process than those with a cationic photoinitator. Moreover, the formulations without diluent can be cured with lower radiation energy than those with diluent.

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Ph Dependant Coating For Microfluidics Devices, L Limsavarn, C Panithipongwut, P Thongkorn, S T. Dubas Dec 2006

Ph Dependant Coating For Microfluidics Devices, L Limsavarn, C Panithipongwut, P Thongkorn, S T. Dubas

Journal of Metals, Materials and Minerals

The layer-by-layer technique was used to coat the channels of PDMS microfluidics devices. The coating was based on the sequential deposition of polydiallyldimethylammonium chloride (PDADMAC) with a copolymer of polystyrene sulfonate and maleic acid (CoPSS-Maleic) into polyelectrolyte multilayer (PEM). The possible deposition of PEM coating on PDMS was confirm by contact angle which showed the clear transformation of the PDMS surface from hydrophobic to hydrophilic. The later deposition of the PEM coating inside the micro-channels was confirmed by change in electroosmotic flow direction (EOF) and intensity as a function of the number of deposited layers. The EOF measurements revealed that …

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Techniques To Improve Coating Adhesion Of Superhard Coatings, N Panich, P Wangyao, N Vattanaprateep, S Yong Dec 2006

Techniques To Improve Coating Adhesion Of Superhard Coatings, N Panich, P Wangyao, N Vattanaprateep, S Yong

Journal of Metals, Materials and Minerals

This work addresses the development of different techniques in fabricating TiB2 coatings with increased adhesion to the substrate and with retained high hardness. Titanium diboride (TiB2) coatings were deposited on high-speed steel substrates by magnetron sputtering of a TiB2 target. Attempts to enhance the coating adhesion to the substrate of the TiB2 coatings by controlling the deposition conditions and parameters are presented, such as effect of substrate rotation; annealing temperature; using deposited Cr as an interlayer material and Ti/TiB2 multilayer system. The structure of the coatings was examined by X-ray diffraction, field-emission scanning electron microscopy, and atomic force microscopy. The …

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Electrochemical Oxidation Process For Mineralization Of Solvent, A Charoensri, F Kobayashi, A Kimura, J Ishii Dec 2006

Electrochemical Oxidation Process For Mineralization Of Solvent, A Charoensri, F Kobayashi, A Kimura, J Ishii

Journal of Metals, Materials and Minerals

A silver mediated electrochemical oxidations is a promising technique for the destruction of organic compounds. The destruction of 30%tributyl phosphate in dodecane in a nitric acid medium containing electrogenerated Ag(II) to carbon dioxide was studied by using a laboratory scale electrochemical oxidation cell. The electrolyte used in this system was 0.5 M AgNO3 in the range of 3 - 7 M HNO3, at operating temperatures of 60ºC ± 5ºC, under ultrasonic agitation and the output of a DC power supply at constant the current was 60 A, respectively. Electrolysis was carried out for 5 hours. The results show that, in …

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Reheat Treated Microstructures And Gamma Prime Particle Coarsening Behaviour At 900˚C Of Cast Nickel Based Superalloy In-738, S Polsilapa, P Sopon, N Panich, N Chuankrerkkul, A Thueploy Dec 2006

Reheat Treated Microstructures And Gamma Prime Particle Coarsening Behaviour At 900˚C Of Cast Nickel Based Superalloy In-738, S Polsilapa, P Sopon, N Panich, N Chuankrerkkul, A Thueploy

Journal of Metals, Materials and Minerals

Long-term isothermal exposure tests were conducted on IN-738 alloy to evaluate the variation of gamma prime particle coarsening behavior after different rejuvenated heat treatment conditions. The longterm thermal exposure tests (up to 2,500 hours) were conducted at 900˚C to assess gamma prime particle coarsening behavior. Metallographic work had been performed on isothermally aged samples to characterize gamma prime coarsening as a function of heating time. At all investigated heating times, the gamma prime particles in all tested specimens were coarser than the initial reheat treated ones. The gamma prime particles appeared to coarsen more into a round shape or agglomerated …

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Effect Of Decarburization On Microstructure Of Dc-Plasma Nitrided H 13 Tool Steel, P Visuttipitukul, C Paa-Rai, K Hideyuki Dec 2006

Effect Of Decarburization On Microstructure Of Dc-Plasma Nitrided H 13 Tool Steel, P Visuttipitukul, C Paa-Rai, K Hideyuki

Journal of Metals, Materials and Minerals

Decarburization may occur during heat treatment of H13 steel resulting in carbon deficiency near the specimen surface. Microstructures and properties of H13 tool steel after surface treatment such as plasma nitriding can be affected by decarburization. This study is focused on the microstructure of plasma nitrided H13 steel. Decarburized and non-decarburized H13 steel was plasma nitrided for 36-72 ks at temperatures varying from 773 to 823 K. The microstructure of the plasma nitrided layer was analyzed by an optical microscope and Electron Probe Micro Analysis (EPMA). The thickness of the nitriding layer is measured. The microstructures of the decarburized and …

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The Influence Of The Strain Rate On The Material Properties Of The Zinc-Coated Sheet, Z Vadasová, M Mihaliková Dec 2006

The Influence Of The Strain Rate On The Material Properties Of The Zinc-Coated Sheet, Z Vadasová, M Mihaliková

Journal of Metals, Materials and Minerals

In this paper the influence of the strain rate on the material properties of the zinc-coated sheet of the thickness (1; 1.5; 1.8) mm made from low-alloyed steel ZINKODUR 340 was analyzed. Increasing the strain rate is one of the possible ways to increase cold mechanical work in products. The tensile test is the most useful method for determining the material characteristic such as ductility. This contribution analyzes the influence of loading rate in range from 1 to 1000mm/min on material characteristics of tested steel during the tensile test. Strain rate is one of the most significant factors, which affected …

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The Effect Of Long-Term Thermal Exposure At Elevated Temperatures On Microstructures And Mechanical Properties In Centrifugally Casted Iron-Base Alloy, G Lothongkum, N Thaweepornkhasemsukh, P Wangyao Dec 2006

The Effect Of Long-Term Thermal Exposure At Elevated Temperatures On Microstructures And Mechanical Properties In Centrifugally Casted Iron-Base Alloy, G Lothongkum, N Thaweepornkhasemsukh, P Wangyao

Journal of Metals, Materials and Minerals

This work has an aim to study and investigate the relationship between high temperature exposure conditions on microstructural evolution and mechanical properties in the iron-based alloy, Fe-30.8 Ni - 26.6 Cr alloy, strengthened by carbide precipitation. Two exposure temperatures (900 and 1000°C) with various thermal exposure times are introduced to the as-received alloy. After short-term exposure, it was found that the secondary carbides precipitated early near the primary carbides, which were chromium and niobium/titanium carbide networks. The secondary carbide precipitations were also found in the dendrite cores. The amounts of needle-like carbides and secondary carbide films increased with time and …

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Transparent Coating Materials Based On Inorganic/Organic Composites, K Srikulkit, N Rojtinnakorn, R Charoensak Dec 2006

Transparent Coating Materials Based On Inorganic/Organic Composites, K Srikulkit, N Rojtinnakorn, R Charoensak

Journal of Metals, Materials and Minerals

A siloxyl group functionalized copolymer of low molecular weight was synthesized, aiming at preparing transparent inorganic/organic coating composites. Two types of coating systems were investigated: two-component system (based on functionalized copolymer-HMMM) a three-component system (based on functionalized copolymer-HMMM-TEOS). Their properties were investigated and compared. Coating films obtained from these systems exhibited good optical clarity, which was largely dependent on the content of indicated Materials. For instance, to prevent phase separation in the 3- component system, TEOS was "effectively" linked to pendent siloxyl groups on the organic moiety Hence, coating formulations containing a high degree of pendent siloxyl groups exhibited better …

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Drawing Quality Steel Sheet Under Tension And Bending Condition, M Mihaliková, M Buršák Jul 2006

Drawing Quality Steel Sheet Under Tension And Bending Condition, M Mihaliková, M Buršák

Journal of Metals, Materials and Minerals

The paper analyzes the influence of the loading rate in the interval from 1 to 1000 mm/min on the mechanical properties of drawing quality steel sheet with the gauge of 1 mm, used for the manufacturing of automotive parts, under tension and bending conditions. It describes the aspects of material characteristics under tension and bending conditions, while bending tests were made on notched specimens (a modified impact bending test). The paper presents knowledge that using a modified notch toughness test. It is possible to achieve the pressability (formability) characteristics corresponding to dynamic strain rates even under the static loading.

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Fractures Of As-Cast Low-Carbon Steels In The Plasticity Degradation Area At High Testing Temperatures, A Ševčík, J Ševčíková Jul 2006

Fractures Of As-Cast Low-Carbon Steels In The Plasticity Degradation Area At High Testing Temperatures, A Ševčík, J Ševčíková

Journal of Metals, Materials and Minerals

The work studies the fractures of low-carbon steels after tensile tests in a temperature interval from ca 1200°C, where a plasticity degradation takes place, up to the liquid phase formation temperature. Statistical analyses of the temperature dependence of the reduction of area were made with the aim to determine integral effects of the chemical composition on the plasticity course. In the plasticity degradation temperature area, intercrystalline fractures occur, which have several morphologies, even within the same steel grade. Besides typical intercrystalline fractures, a fine-grained, interdendritic fracture often occurs. A specific case is the failure of steels in the γ + …

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Mechanical Properties Of Skin Wounds After Atropa Belladonna Application In Rats, T Toporcer, T Grendel, B Vidinský, P Gál, J Sabo, R Hudák Jul 2006

Mechanical Properties Of Skin Wounds After Atropa Belladonna Application In Rats, T Toporcer, T Grendel, B Vidinský, P Gál, J Sabo, R Hudák

Journal of Metals, Materials and Minerals

Atropa belladonna is a topical agent used in the treatment of skin wounds in Slovak folk medicine. The aim of this study was to asses the effect of A. belladonna extract on wound tensile strength in Sprague-Dawley rats. Twenty four rats were randomly divided into 3 groups of 8 animals. Two symmetrical skin incisions were performed on the back of each animal and immediately sutured. In the 1st group A. belladonna extract was not applied and the group served as a control. The animals in the 2nd group were treated by daily application of A. Belladonna extract during the first …

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Kinetics Of Carbonisation, Microstructure And Properties Of Al-Al4c3 System Prepared By Mechanical Alloying, M Besterci Jul 2006

Kinetics Of Carbonisation, Microstructure And Properties Of Al-Al4c3 System Prepared By Mechanical Alloying, M Besterci

Journal of Metals, Materials and Minerals

The method of mechanical alloying process is described. Carbon transformation to carbide Al4C3 is characterised within different heat treatment schedules and nine commercial carbon powders are tested. The micromechanism of carbon incorporation into the metallic powder, and the compacting of it are described. The influence of dispersed carbides on mechanical properties is evaluated together with the influence of deformation on microstructure and properties.

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Comparison Of Gelatin And Collagen Scaffolds For Fibroblast Cell Culture, J Ratanavaraporn, S Damrongsakkul, N Sanchavanakit, T Banaprasert, S Kanokpanont Jul 2006

Comparison Of Gelatin And Collagen Scaffolds For Fibroblast Cell Culture, J Ratanavaraporn, S Damrongsakkul, N Sanchavanakit, T Banaprasert, S Kanokpanont

Journal of Metals, Materials and Minerals

Gelatin and collagen were used to produce the scaffold for fibroblast cell culture. The properties of scaffolds obtained from type A and type B gelatin were compared to scaffold obtained from collagen, which is widely used in skin substitute. Porous scaffolds were prepared by freeze drying and dehydrothermal (DHT) crosslinking method. DHT treatment time was performed at 24 and 48 h and the degree of crosslinking was determined by 2,4,6-trinitrobenzene sulphonic acid (TNBS). The morphology of scaffolds was investigated by scanning electron microscopy (SEM). The compressive modulus and swelling ratio of the scaffolds were reported. To confirm the applicability of …

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Modified Vegetable Oil In Textile Finishing Applications, N Jiratumnukul, P Antarasane Jul 2006

Modified Vegetable Oil In Textile Finishing Applications, N Jiratumnukul, P Antarasane

Journal of Metals, Materials and Minerals

Water-repellent finishing is an important process in textile industries as well as other finishing processes. Coating on the fabric can be used to achieve a substantial water-repellent effect. Using polymeric coatings, however, provided some disadvantages in air and water vapour permeability causing undesirable feelings when wearing. Besides, the fabric treated with polymeric coatings will impart a stiffening appearance, which is undesirable. In this study, water repellents have been prepared from various vegetable oils with different amounts of saturation in fatty acid moiety. Vegetable oil was transesterified with an intermediate fluorinated compound to give modified fatty esters. These fatty esters were …

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The Relationship Between Reheat-Treatment And Hardness Behaviour Of Cast Nickel Superalloy, Gtd-111, P Wangyao, V Krongtong, P Tuengsook, W Hormkrajai, N Panich Jul 2006

The Relationship Between Reheat-Treatment And Hardness Behaviour Of Cast Nickel Superalloy, Gtd-111, P Wangyao, V Krongtong, P Tuengsook, W Hormkrajai, N Panich

Journal of Metals, Materials and Minerals

he microstructure of cast polycrystalline nickel base superalloy, GTD-111, operated for long-term services were investigated by SEM after different re-heat-treatment conditions. It was found that the exposed specimen after long-term service could be recovered in some extent by re-solution treatment followed by two-step aging treatment. The obtained dispersed precipitation of gamma prime particles was more uniform than those of the long-term exposed microstructure. The results showed that the couple of the lower (1125°C) and/or higher (1175°C) solution annealing temperatures resulted in less total volume fraction of coarse gamma prime precipitates and less homogeneous distribution in microstructure than the medium (1150°C) …

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Creep Behavior Of Linear Low-Density Polyethylene Films, Y B. Unigovski, A L. Bobovitch, E M. Gutman Jul 2006

Creep Behavior Of Linear Low-Density Polyethylene Films, Y B. Unigovski, A L. Bobovitch, E M. Gutman

Journal of Metals, Materials and Minerals

The Creep of biaxially-orientated linear low-density polyethylene (LLDPE) non-crosslinked and crosslinked with β-irradiation was studied as a function of the draw ratio and irradiation dose. The creep results have shown an increase in the creep strain after the polymer irradiation with a dose below 4 Megarad (MR) in comparison with a non-irradiated film. This increase corresponds to the disorientation in the amorphous phase, which takes place as a result of the film heating during irradiation. This disorientation was demonstrated by differential scanning calorimetry (DSC) and X-ray analysis.

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Properties Of Collagen/Chitosan Scaffolds For Skin Tissue Engineering, C Tangsadthakun, S Kanokpanont, N Sanchavanakit, T Banaprasert, S Damrongsakkul Jul 2006

Properties Of Collagen/Chitosan Scaffolds For Skin Tissue Engineering, C Tangsadthakun, S Kanokpanont, N Sanchavanakit, T Banaprasert, S Damrongsakkul

Journal of Metals, Materials and Minerals

Biopolymer blends between collagen and chitosan have the potential to produce cell scaffolds with biocompatible properties. In this study, porous scaffolds were fabricated by freeze drying the solution of collagen and chitosan and crosslinked by dehydrothermal treatment (DHT). Various types of scaffolds were prepared by varying compositions of collagen and chitosan. The scaffolds were fully characterized by Fourier transform infrared (FT-IR) spectroscopy. The results proved that collagen and chitosan scaffolds in all blending compositions contained only physical but not chemical interaction in molecular level. The compressive modulus from a universal mechanical testing machine decreased with increasing the compositions of chitosan. …

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Multilayered Systems Of Nanostructured Tib2 Thin Films And Its Mechanical Properties, N Panich, P Wangyao, S Hannongbua, P Sricharoenchai, S Sun Jul 2006

Multilayered Systems Of Nanostructured Tib2 Thin Films And Its Mechanical Properties, N Panich, P Wangyao, S Hannongbua, P Sricharoenchai, S Sun

Journal of Metals, Materials and Minerals

This study focuses on the development of single and multilayer TiB2 coatings with Ti interlayer with the aim of improving the mechanical integrity of the coating-substrate system. The nanostructured TiB2 thin films and multilayered coatings were deposited on high speed steel substrates by magnetron sputtering. The resultant coating systems were evaluated with respect to microstructure, fractured cross-section and fundamental properties such as cross-sectioned fracture, surface roughness, hardness, modulus and coating adhesion to the substrate. It was found that the adhesion strength of TiB2 coating to HSS substrate could be significantly enhanced in the multilayer system, and by a proper combination …

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