Jusami | Indonesian Journal of Materials Science
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REVIEW KEGIATAN LITBANG SUPERKONDUKTOR Tc TINGGI DI P3IB-BATAN
Full text linkREVIEW KEGIATAN LITBANG SUPERKONDUKTOR Tc TINGGI DI P3IB-BATAN. Makalah ini merupakan tinjauan tentang kegiatan litbang superkonduktor Tc tinggi (STT) di Bidang Bahan Maju, P3IB-BATAN. Kegiatan litbang bertujuan untuk menguasai proses sintesis pelet, komposit, dan lapisan tipis STT jenis Y-123 dan Bi-2223 untuk diaplikasikan. Aplikasi STT diawali dengan pembuatan alat peraga fenomena superkonduktivitas untuk sekolah menengah umum dan universitas. Selanjutnya melangkah ke jalur aplikasi industri, yakni pembuatan prototip Fault Current Limiter (FCL) untuk mendukung industri tenaga listrik nasional. FCL merupakan bentuk aplikasi langsung pelet STT. Sintesis pelet dilakukan dengan metode reaksi padatan dan kimia basah. Faktor kunci keberhasilan sintesis pelet STT dengan metode tersebut adalah proses perlakukan panas (kalsinasi dan sintering). Kualitas pelet, terutama sifat listriknya, ditingkatkan dengan menambahkan sejumlah kecil unsur perak (diperoleh pelet STT komposit) dan dengan proses pelelehan (diperoleh pelet STT bertekstur). Pelet STT dijadikan sebagai target pada pembuatan lapisan tipis STT dengan metode unbalanced dc magnetron sputtering (UMBS). Aplikasi lapisan tipis STT belum dikembangkan di P3IB hingga saat ini
EFFECT OF AGAR AND KAPPA-CARRAGEENAN ON THERMAL AND MECHANICAL PROPERTIES OF THERMO PLASTIC STARCH (TPS)
Full text linkEffect of Agar and kappa-Carrageenan on Thermal and Mechanical Properties of Thermo Plastic Starch (TPS) Thermoplastic starch needs to be blend with other materials because of its limited properties. In order to gain the desired properties, the interaction between the added component (filler, plasticizer, second polymer, etc) must be concerned as it can affect the performances of the final product. Thermoplastic starch has been successfully made with mixing and compression molding with the addition of agar and kappa-carrageenan. The effect of the added material has been studied with FTIR, Tensile, DSC, and TGA to investigate their mechanical and thermal properties. The FTIR spectrum has shown the shifting around the methyl group (C-H), a carboxyl group (C-O), and a hydroxyl group (O-H). Thermal analysis results presented different patterns in melting and degradation behavior. The tensile strength value did not show significant improvement with the presence of agar and kappa-carrageenan. It is shown that the addition of agar and kappa-carrageenan affects thermal behavior but does not significantly impact the mechanical properties.
SYNTHESIS POLYMER MATRIX COMPOSITE EPOXY FeNdB-Cu FOR RADAR ABSORBER COATING APPLICATION
Full text linkSYNTHESIS POLYMER MATRIX COMPOSITE EPOXY FeNdB-Cu FOR RADAR ABSORBER COATING APPLICATION. Radar (Radio Detection and Ranging) is a technology using the principle of electromagnetic for detecting, measuring, and mapping target coordinates. So stealth technology was created to tackle these threats, one of which is the radar absorber coating method (RAC). This research aims to identify the effect addition of Cu to Fe-Nd-B radar absorber material as polymer matrix composite (PMC). The processes were done by powder metallurgy method, started by milling and mechanical alloying process using planetary ball mill for 60 minutes 1000 rpm, 25 kg/mm2 of compaction load, and sintering at the temperature 1000 oC for 3 hours. The coating process was carried out conventional method as much as 1 layer, the variation of resin and magnetic powder are (95:5), (90:10), and (85:5) with the addition of Cu 1%wt. Based on the characterization the lowest RL was obtained at the composition (85:15) with the value 32.08 dB at the frequency of 10.36 GHz, magnetic characterization after doping addition coercivity 0.096 kOe and Saturation 5.22 kG. PMC hardness was raising following to addition of magnetic powder with the 29.2 HD Shore D, and adhesivity value was decreased following to addition of magnetic powder to 0.5 MPa
GLASS-CERAMICS: THEIR PRODUCTION FROM WASTES
Full text linkGLASS-CERAMICS: THEIR PRODUCTION FROM WASTES. Glass-ceramics are fine, polycrystalline materials that are produced by the controlled crystallization (devitrification) of a glass. The fundamental principles of the crystallization are presented briefly and the various processing methods for glass-ceramics described in light of these fundamental principles. Two examples of the production of glass- ceramics from wastes are discussed in detail; the wastes are slag from steel production and fly ash from incineration
EFFECT OF TREATMENT SOLUTION ON THE MICROSTRUCTURE AND MICROHARDNESS OF TERNARY Ni-Al-Nb ALLOY DOPED WITH TITANIUM
Full text linkEFFECT OF TREATMENT SOLUTION ON THE MICROSTRUCTURE AND MICROHARDNES OF TERNARY Ni-Al-Nb ALLOY DOPED WITH TITANIUM. Nickel-based superalloys have been widely used in various applications, which require high strength at high temperatures. Most types of these superalloys is age-hardenable because they have γ’ particles' chemical composition Ni3(Al, Ti) in γ’-phase matrix. This research will be used alloy Ni-Al-Nb added alloying elements Ti. This research was conducted to study the mechanical properties, microstructure conditions in some alloys Ni-Al-Nb added distinction Titanium element (0,5% and 1% Ti) using the method of aging temperature variation performed at a temperature of 650 °C,700 °C and 750 °C with a holding time 4 hours and air cooling. Tests were conducted to determine the characterization of the specimen includes testing metallographic optical microscope, Rockwell hardness C and SEM- EDS,XRD. Results obtained from this research that addition of titanium element affecting the hardness values as well as the results of the cast, solution treatment and aging process results. The 1% Titanium content can affect the gamma prime coarsening and make the grain on the microstructure result smooth
THE PHYSICOCHEMICAL CHARACTERISTICS OF RECYCLED-PLASTIC PELLETS OBTAINED FROM DISPOSABLE FACE MASK WASTES
Full text linkTHE PHYSICOCHEMICAL CHARACTERISTICS OF RECYCLED-PLASTIC PELLETS OBTAINED FROM DISPOSABLE FACE MASK WASTES. The government policy to wear a face mask during the COVID-19 pandemic has increased disposable face mask wastes. Thus, to reduce such wastes, it is necessary to evaluate the physicochemical characteristics of disposable face masks wastes before the recycling process and the recycled products. In this study, physicochemical characterization of the 3-ply disposable face masks and the recycled plastic pellets after disinfection using 0.5% v/v sodium hypochlorite were evaluated. A set of parameters including the characterization of surface morphology by a scanning electron microscope (SEM), functional groups properties by a fourier transform infra-red spectroscopy (FT-IR), thermal behavior by a differential scanning calorimetry (DSC), tensile strength and elongation at break were evaluated. The surface morphological of each layer 3-ply disposable face mask showed that the layers were composed of non-woven fibers. The FT-IR evaluation revealed that 3-ply disposable face mask was made from a polypropylene. At the same time, the DSC analysis found that the polypropylene was in the form of homopolymer. The SEM analysis showed that the recycled plastic pellets showed a rough and uneven surface. The FT-IR, tensile strength and elongation at break of the recycled plastic pellets showed similarity with a virgin PP type CP442XP and a recycled PP from secondary recycling PP (COPLAST COMPANY). In summary, recycling 3-ply disposable face mask wastes to become plastic pellets is recommended for handling disposable face mask wastes problem
PREPARATION OF HYDROXYAPATITE POWDERS FOR MEDICALAPPLICATIONS VIA SOL-GEL TECHNIQUE
Full text linkPREPARATION OF HYDROXYAPATITE POWDERS FOR MEDICALAPPLICATIONS VIA SOL-GEL TECHNIQUE. Hydroxyapatite (HA) powders have been prepared via sol-gel procedure using calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate as the precursors for calcium and phosphorus, respectively. An ammoniacal solution of the monomers was heated at 100°C for about 3 –4 h until a white gel of hydroxyapatite mixture were obtained. The obtained gel was then dried at 340°C for 7 h and subsequently subjected to an 820°C calcination for 2 h. The yield of the powder mixture ranged between 50 to 53 g. XRD measurement shown that the powder contained hydroxyapatite crystal with b-TCP ( 15-20%) and calcium oxide (4-6%) as secondary phases. Further treatment was conducted to gain hydroxyapatite powder of higher purity, thus the correct Ca/P ratio, by adding an appropriate amount of di-ammonium hydrogen phosphate and heated while stirring at 90°C for 4 h. Good purity (almost 100%) of the obtained hydroxyapatite was confirmed by XRD analysis.This result proved that our HA powder meets the medical prerequisite: a HA purity of above 95%. Morphological evaluation by SEM measurement shows that the particles of the HA agglomerate are globular in shape with an average size of 1-2 mm in diameter. Meanwhile, the primary particles have a diameter of 70-150 nm in average. Surface area of the powder is 7 m2/g and the mean particle size as measured using X ray sedimentation method is ca. 1 mm. The measurements are not in good agreement with the morphological investigation. We consider, accordingly, that the particles presumably have high surface potentials, thus forming very tightly bonded agglomerate
