Anne Zulfia
Departement Metalurgy dan Material, Fakultas Teknik, University Indonesia

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HIBISCUS FIBER CARBON FOR FUEL CELL DEVICE MATERIAL Indayaningsih, Nanik; Zulfia, Anne; Priadi, Dedi; ., Suprapedi
Jurnal Sains Materi Indonesia 2010: Desember 2010 - Edisi Khusus
Publisher : BATAN

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Abstract

The objective of this research is carbon of hibiscus fibers for the application as basic material of fuel cell device. The carbon is made using a pyrolysis process in inert gas (nitrogen) for 1 hour at temperature of 500 oC, 700 oC and 900 oC. The X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Impedance-Capacitance-Resistance-meter are used to find out the microstructure, morphology and electrical properties respectively. The results of the experiment showed that the carbon had a structure of amorphous, and as the semiconductor material the electrical conductivity was 5 x 10-5 S.cm-1 to 4.9 x 10-5 S.cm-1 increasing in accordance with the pyrolisis temperature. The morphology resembled to plaited mats constructed by porous fibers having width of 50 µm to 300 µm, thickness of 25 µm to 35 µm, and the porous size of 0.5 µm to 5 µm. This morphology enables carbon to be applied as a candidate for a basic material of the Proton Exchange Membrane Fuel Cell.Keywords: Carbon, Hibiscus fiber, Pyrolysis, Electrical conductivity.
SYNTHESIS OF EMPTY FRUIT BUNCHES CARBON POLYMER COMPOSITES AS GAS DIFFUSION LAYER FOR ELECTRODE MATERIALS Indayaningsih, Nanik; Zulfia, Anne; Priadi, Dedi; Kartini, Evvy
Jurnal Sains Materi Indonesia Vol 14, No 2 (2013): Januari 2013
Publisher : BATAN

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Abstract

Empty Fruit Bunches (EFB) of oil palm has been used, for example, for biofuels, automotive components, particle board, as a carbon source. Carbon material scan be widely used for many applications, for hydrogen storage, conductive or reinforcement plastics, catalyst supports, batteries and fuel cells. In this study, EFB carbon powder has been used as a raw material to make sheets of carbon-polymer composites. The composition of the composite sheet was varied, the electrical properties of the sheets were measured to determine the potential application as a Gas Diffusion Layer for Proton Exchange Membrane Fuel Cell (PEMFC) electrodes. Composites made with carbon composition weight % compared to the polymer are 65/35, 70/30, 75/25 and 80/20. The materials used is EFB carbon powder as a result of the pyrolysis temperature of 900 °C for 1 hour, then crushed and sieved to 200 mesh size, and the polymer was ethylene vinyl acetate. The raw materials are mixed in a solvent xylene, and printed using tape casting method, then dried at room temperature. The electrical properties were tested using a HIOKI 3522-50 LCR meter HiTESTER The measurement results show that the greater the ratio of carbon to polymer, the higher the electrical conductivity, the values are between 1.54 S/m-11.34 S/m. Morphology of the composite sheet was observed using Scanning Electron Microscope (SEM) to determine the distribution of carbon and polymer. According to the measurement of morphology and electrical conductivity, the composite is suitable for the gas diffusion layer of the PEMFC electrode.Keywords: Composite, Empty fruit bunches, Gas diffusion layer, Electrical conductivity.
PROSES PENUAAN (AGING) PADA PADUAN ALUMINIUM AA 333 HASIL PROSES SAND CASTING Zulfia, Anne; Juwita, Ratna; Uliana, Ari; Jujur, I Nyoman; Raharjo, Jarot
Jurnal Teknik Mesin Vol 12, No 1 (2010): APRIL 2010
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (462.355 KB) | DOI: 10.9744/jtm.12.1.13-20

Abstract

The use of aluminum alloys AA 333 as automotive component is progressively expand with the expanding desire to lose weight from the used component. However, the as-cast product from aluminum alloys AA 333 is still having low mechanical properties, so it needs the other process to increase the hardness value; one of the processes is through heat treatment process. The heat treatment process for this materials is T6 process (artificial aging), including: solution treatment at temperature 525 oC for 8 hour, quenching and various time of aging process. Aging was conducted at 180 oC for 25 minutes, 1 hours, 5 hours, 8 hours and 16 hours respectively. For aging 5 hours, the aging temperature was applied various from 110 oC, 150 oC, 180 oC, 200 oC to 250 oC, so the expected result from this research is to know the influence of the variation to morphological change of microstructure and hardness value of aluminum alloys AA 333. The results had indicated that the aging process at 180 oC caused the increased of the hardness value of each phases: ?-Al matrix, primary silicon, eutectic Al-Al2Cu and Al15 (Fe, Mn)3Si2 and also caused the increased of the hardness value of aluminum alloys AA 333, from the condition of as-cast, as-quench, aging process for 25 minutes, 1 hours, 5 hours, 8 hours and 16 hours. And others results had indicated that the aging process for 5 hours also caused increasing of hardness value of each phases. The aging process (at 180 oC) for 8 hours and 5 hours) represented the most optimum time to obtained the best combination from phase distribution, that spread over in the rich matrix of aluminum and the size measured from each phase, therefore giving the highest hardness value. Abstract in Bahasa Indonesia: Penggunaan paduan aluminium AA 333 sebagai komponen otomotif semakin berkembang bersamaan dengan semakin berkembangnya keinginan untuk mengurangi berat dari komponen yang digunakan. Namun paduan aluminium AA 333 as-cast masih memiliki sifat mekanis yang rendah sehingga diperlukan proses lain untuk meningkatkan kekerasannya, salah satunya melalui proses perlakuan panas. Proses perlakuan panas yang dipilih dalam penelitian ini adalah proses perlakuan panas T6 (artificial aging), yang meliputi tahapan: solution treatment pada temperatur 525oC selama 8 jam, quenching dan proses aging. Variabel yang digunakan dalam penelitian ini adalah variasi waktu aging (temperatur 180oC), yaitu 25 menit, 1 jam, 5 jam, 8 jam dan 16 jam dan variasi temperatur aging (waktu aging 5 jam), yaitu 110oC, 150oC, 180oC, 200oC, 250oC. Dari penelitian ini diharapkan dapat diketahui pengaruh dari variasi tersebut terhadap perubahan struktur mikro dan nilai kekerasan paduan aluminium AA 333. Hasil penelitian menunjukkan bahwa aging temperatur 180oC menyebabkan peningkatan kekerasan dari tiap fase: matrik ?-Al, silikon primer, eutektik Al-Al2Cu dan Al15(Fe,Mn)3Si2 dan menyebabkan peningkatan kekerasan paduan aluminium AA 333, dari kondisi as-cast, as-quench, dan waktu aging 25 menit, 1 jam, 5 jam, 8 jam dan 16 jam. Hasil penelitian lainnya juga menunjukkan bahwa proses aging selama 5 jam juga menyebabkan peningkatan kekerasan dari tiap fase. Waktu aging (pada temperatur 180oC) selama 8 jam dan temperatur aging (selama 5 jam) pada 180oC merupakan waktu yang paling optimum untuk memperoleh kombinasi yang terbaik dari distribusi fase, yang tersebar merata dalam matrik kaya Al, dan ukuran dari masing-masing fase sehingga menghasilkan nilai kekerasan yang tertinggi. Kata kunci: Aluminium AA333, penuaan buatan (T6), kekerasan, struktur mikro.
PENGARUH WAKTU AGING TERHADAP KEKERASAN DAN STRUKTUR MIKRO KOMPOSIT Al-Si-Mg/Al2O3 DENGAN METODE STIR CASTING Junus, Salahuddin; Zulfia, Anne; Melisa, Melisa; Mariani, Lilis
ROTOR Vol 7, No 2 (2014)
Publisher : ROTOR

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Abstract

Aluminum composite needs proper aging period to achieve its optimum mechanical properties through  precipitation hardening process. In this research, alumina (Al2O3) particulate reinforced aluminum alloy 6061 composite which is fabricated by stir casting method, undergoes T6 treatment in 175°C for 2 hours, 4 hours, 6 hours, and 8 hours. Mechanical properties evaluations such as tensile testing, hardness testing,  and wear rate testing; also microstructure and SEM observation are conducted. Research shows that the  optimum  artificial aging period for the aluminum composite is 6 hours in 175°C. Wear rate decreases after T6 treatment  applied. Hardness  increases after T6 treatment applied with aging period of 4 and 6 hours. Tensile strength decreases compared to as-cast composite due  to  formation  of  void  at  interface  when T6 treatment conducted. Manufacturing factors will affect the mechanical properties of composite. Keywords: Aluminum composite, billet Al.6061, T6, aging period, stir casting
Effect of Copper Addition on Mechanical Properties and Electrical Conductivity of PP/C-Cu Bipolar Plate Composites Zulfia, Anne; Abimanyu, Taufik; Dalam, Verina
Makara Journal of Technology Vol 15, No 2 (2011)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (356.489 KB) | DOI: 10.7454/mst.v15i2.209

Abstract

Bipolar plate is a major component in PEM fuel cell which possess main function of collecting and removing electrons from anode to cathode. Therefore, materials for bipolar plates produced must have high electrical conductivity. To obtain bipolar plate materials which is cheap, lightweight and high conductivity, so it is developed bipolar plates material based on PP/C-Cu composite. PP/C-Cu composites has been made by mixing all materials then compounding, rheomix, hot blending and hot press. Cu (Copper) has been used various from 0.1 wt%, 1 wt% to 2 wt% to increase electrical conductivity of PP/C-Cu composite. It is found that the effect of Cu addition in PP/C-Cu composite has increased tensile strength, flexural strength, flexural modulus, tensile modulus, elongation, electrical conductivity and decreasde porosity, unfortunately the value of electrical conductivity was still lower than standard requirement for bipolar plate fuel cell.
Effect of Firing Temperature and Holding Time on Characterization of Al/SiC Metal Matrix Composites Produced by Pressureless Infiltration. Zulfia, Anne; Ariati, Myrna
Makara Journal of Technology Vol 10, No 1 (2006)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (262.704 KB) | DOI: 10.7454/mst.v10i1.106

Abstract

 The production of Al-SiC metal matrix composite can be carried out by pressureless metal infiltration processs (PRIMEX). The experiment was conducted using aluminium AC2B ingot as a matrix and 50%Vf SiC powder as a reinforcement which is mixed with  10% Mg powder for wetting agent. The variables of this experiment are holding time and firing temperature to investigate the effect of these conditions on mechanical properties of Al-SiC metal matrix composites. Holding time was conducted for 2,5,8,10,12 hours and firing temperatures was 750, 800, 900, 1000, 1100°C respectively.. The composites produced are analysed both mechanical properties and metalography such as densities, porosities, hardness, as well as wear rate. The results showed that the longer holding time and increasing firing temperature will increase mechanical properties of Al-SiC metal matrix composites, and it is found that the optimum mechanical properties at 1000°C for 10 hour.
Konduktifitas Listrik Komposit Polimer Polipropilena/Karbon Untuk Aplikasi Pelat Bipolar Fuel Cell Pramono, Agus; Zulfia, Anne
Setrum : Sistem Kendali-Tenaga-Elektronika-Telekomunikasi-Komputer Vol 1, No 1 (2012): Edisi Juni 2012
Publisher : Fakultas Teknik Elektro - Universitas Sultan Ageng Tirtayasa

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Abstract

Proton exchange membrane fuel cell (PEMFC) merupakan salah satu sumber energi alternatif yang saat ini sedang dikembangkan untuk mengatasi permasahan krisis energi dan lingkungan. Salah satu komponen yang mempunyai peran  signifikan dalam efisiensi biaya dan proses PEMFC adalah pelat bipolar. Untuk itu diperlukan pelat bipolar yang ringan, murah, dan mudah diproduksi secara masal. Dalam penelitian ini dikembangkan komposit pelat bipolar menggunakan matriks polipropilena (PP), penguat karbon hitam dan grafit elektroda dengan variasi komposisi wt% PP/grafit/CB sebesar 85:10:5; 75:20:5; 65:30:5;dan 55:40:5, sehingga mendapatkan sifat daya hantar listrik yang baik. Sifat-sifat dari komposit yang dihasilkan diuji dengan pengujian konduktivitas, Dari keempat formula, didapatkan bahwa sifat listrik yang paling baik terdapat pada formula empat dengan penambahan grafit sebesar 40 wt%. Formulasi empat memiliki konduktivitas listrik sebesar 2,523E-03 S/cm. sifat listrik juga belum optimal dikarenakan masih terdapatnya banyak rongga atau pori dalam komposit PP/grafit/CB yang disebabkan oleh udara yang terjebak selama proses penekanan.
SINTESIS DAN KAJIAN PERILAKU KONDUKTIVITAS KOMPOSISI BARU ELEKTROLIT PADAT (Li2O)x(P2O5)y Jodi, Heri; Zulfia, Anne; Sudjatno, Agus; Wahyudianingsih, Wahyudianingsih; Kartini, Evvy
Jurnal Sains Materi Indonesia Vol 19, No 1: OKTOBER 2017
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (291.68 KB) | DOI: 10.17146/jsmi.2017.19.1.4127

Abstract

Bahan elektrolit padat (Li2O)x(P2O5)y dengan komposisi konten Li2O sebesar x = 24 %berat dan 28 %berat telah dipreparasi menggunakan teknik reaksi padat pada suhu di bawah suhu lelehnya.  Paduan yang telah dipreparasi kemudian dikarakterisasi menggunakan Scanning Electron Microscopy (SEM) dan Electrochemical Impedance Spectroscopy (EIS) untuk diperiksa morfologi, sifat elektrokimia dan konduktivitasnya. Karakterisasi elektrokimia menunjukkan bahwa nilai konduktivitas kedua paduan berada pada orde 10-6S/cm, setara dengan nilai konduktivitas paduan Li4P2O7 yang dipreparasi pada suhu lebih tinggi dengan kandungan Li2O lebih banyak, dan lebih tinggi dari konduktivitas senyawa Li3PO4. Taksiran nilai eksponen frekuensi dari formula konduktivitas AC, memperlihatkan bahwa kemungkinan sumber konduksi ion dalam bahan yang diamati salah satunya adalah aliran ion jarak jauh. Kurva rugi dielektrik menunjukkan bahwa konduksi dalam bahan elektrolit ini didominasi oleh konduksi DC.
EFFECTS OF Al2O3 NANOPARTICLES ADDITION ON HARDNESS AND THERMAL PROPERTIES OF Al-Zr-Ce/Al2O3 WITH 3 Wt-% Mg NANOCOMPOSITE PRODUCED BY STIR CASTING Maulana, Rd. Panji; M., Kirman; W, Agus Sukarto; Zulfia, Anne
Jurnal Sains Materi Indonesia Vol 16, No 2: JANUARI 2015
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (193.859 KB) | DOI: 10.17146/jsmi.2015.16.2.4211

Abstract

EFFECTS OF Al2O3 NANOPARTICLES ADDITION ON HARDNESS AND THERMAL PROPERTIES OF Al-Zr-Ce/Al2O3 WITH 3 Wt-% Mg NANOCOMPOSITE PRODUCED BY STIR CASTING. Al-Zr-Ce alloy reinforced with Al2O3 nanoparticles with 3wt% Mg addition is proposed as one of the alternative material to replaceACSR as aluminum conductor. The composition of the nanocomposite consists of 0.12% Zr, 0.15% Ce, 3% Mg and 0.5-1.5 vf-% Al2O3. Fabrication of the nanocomposite is using stir casting method. Master alloy which consists of aluminum alloyed with Zr and Ce was manufactured. The master alloy was then melted and 3% Mg along with the reinforcement was blended inside the molten metal by stirring with rotational speed of 500 rpm at 850°C in an inert Ar gas environment. Chemical composition test confirmed the composition of alloying elements were close to the design except Ce, that could be related to limitation of OES and fading effect. The density of nanocomposite was decreased, while the porosity was increased with the addition of Al2O3. Nanocomposites’ hardness testing shows hardness increases with further addition of Al2O3, except the composite with 1.5 vf% of reinforcement that had lower hardness. Further addition of Al2O3 reinforcement to nanocomposite reduced its thermal expansion coefficient. SEM observation indicated that the Al2O3 nano particles were agglomerated and did not react to form interface layer. Nanocomposite 1.2 vf-% SEM observation shows that Ce inside of themicro structure did not segregate with Fe and Si, but seemed to react with Mg and Zr.
Influence of Chemical Treatments Sequence on Morphology and Crystallinity of Sorghum Fibers Ismojo, Ismojo; Ammar, Abdul Aziz; Ramahdita, Ghiska; Zulfia, Anne; Chalid, Mochamad
Indonesian Journal of Chemistry Vol 18, No 2 (2018)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (286.62 KB) | DOI: 10.22146/ijc.27194

Abstract

Micro-fibrillated cellulose (MFC) derived from natural fibre is continuously gaining interest to produce an environmentally-friendly material, due to economic and ecological reasons. In consequence, sorghum is one of the most-cultivated crops that usually remain the waste as by product of bioethanol production. Indeed, it will be a promising area to utilize sorghum waste to produce MFC for enhancing polymer performance, especially in terms of crystallinity. The objective of this study is to investigate the effect of a sequence of chemical modification was applied to sorghum fibres, i.e. alkalization using 4% sodium hydroxide followed by bleaching using 1.7% sodium chlorite plus acetic acid as a buffer. The treatment was purposed to unbundle the lignocellulose networks into microfibrils cellulose with less amorphous part and lower hydrophilic properties. Evaluation of the chemical treatments effect on internal microstructure, crystallinity index and chemical composition of sorghum fibre was measured via Field-Emission Scanning Electron microscope (FE-SEM), X-ray Diffraction (XRD) and Fourier Transformation Infra-Red (FTIR) Spectroscopy. The experiments show that treatments led to a removal of binding materials, such as amorphous parts hemicellulose and lignin, from the sorghum fibres, resulting MFC of sorghum fibres and enhanced crystallinity index from 41.12 % to 75.73%.