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All Journal Spektra: Jurnal Fisika dan Aplikasinya Jurnal Teknologi
Widia Nursiyanto
Jurusan Teknik Mesin, Fakultas Teknik, Universitas Pancasila
Aerospace Engineering Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology Physics

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Penelitian Proses Hard Chrome Plating Pada Propeller Turbocharger Berbahan Kuningan S26000 Tri Surawan; Yunus Falah Kaban; Syahbuddin Syahbuddin; Farid Thalib; Widia Nursiyanto
Jurnal Teknologi Vol 7, No 1 (2019): Jurnal Teknologi
Publisher : Universitas Jayabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (396.185 KB) | DOI: 10.31479/jtek.v7i1.34

Abstract

Propeller turbocharger berdiameter 36,47 mm dibuat dalam penelitian ini dengan teknik pengecoran investment. Material yang dipakai dalam pembentukkan propeller menggunakan kuningan dengan seri C26000. Pola propeller berbahan plastik PLA (polylactic acid) yang dicetak menggunakan 3D Printing. Molding dengan pola tersebut yang dibentuk merupakan campuran dari plaster gypsum dan pasir zirkon dengan komposisi 2:1, lalu campuran tersebut ditambahkan air dengan perbandingan 2:1 dan kemudian dituang ke dalam wadah molding berisi pola propeller. Pemanasan molding dilaksanakan dengan dua tahap. Tahap pertama bertujuan untuk melebur pola propeller plastik pada temperatur 500oC selama dua jam. Sementara itu, tahap kedua bertujuan untuk memperkeras molding pada temperatur 900oC selama dua jam. Material kuningan seri C26000 yang memiliki titik lebur 915oC, dilebur menggunakan dapur induksi dan dituang ke molding. Setelah itu, dilakukan pembersihan kemudian di-hard chrome. Pada penelitian ini, propeller kuningan yang belum di-hard chrome memiliki nilai kekerasan 85,33 ± 2,36 HRB dan yang sudah di-hard chrome bernilai 94,00 ± 2,44 HRB. Hasil struktur mikro propeller juga memperlihatkan nilai penyusutan yang ada pada proses pengecoran adalah 5,99%.
PENGARUH GELOMBANG MIKRO (MICROWAVE ASSISTED) TERHADAP KURVA HISTERISIS DARI BAHAN FERROMAGNETIK CoPd BERBENTUK ELLIPSOID Widia Nursiyanto; L Rohman; H.T.B.F Nagara; E Supriyanto
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 3 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 3, December 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (315.998 KB)

Abstract

Abstract Until now the data storage device is still constrained unstable because of the super paramagnetic effect. This effect can occur when the value of bit density increases or when the magnetic energy decreases which causes the process of demagnetization due to the magnetization orientation changed in the presence of high temperature. CoPd as one of the ferromagnetic materials has magnetic anisotropy value and large coercivity of the field, so that this material can be patterned with very small size according to the requirement of data storage tool. However, data analysis of the CoPd hysteresis curve is required when the microwave assisted at the CoPd would give to rise of temperature. Therefore, we observe the value of the coercivity of the field on the ellipsoid CoPd material with the dimension of size the diameter varied. In addition external field, the microwave assisted with the value of amplitude is 10000 mT and the value of frequency is 80 GHz give to the sample. Retrieval of data using a micromagnetic simulation program from a public software called Object Oriented Micromagnetic Framework (OOMMF). From the data processing, it is found that coercivity of the field becomes smaller when dimension of sample are getting bigger, This means that the reversal of magnetization of CoPd is getting smaller. With these results it can be concluded that CoPd are suitable for use as data storage devices. The best dimensions are (150x150x450) nm3 and (165x165x495) nm3. Keywords: CoPd, hysteresis curve, microvawe assisted, coercivity of the field
THE EFFECT OF COBALT CONTENT ON MAGNETIC PROPERTIES OF CoFe ALLOYS Widia Nursiyanto; L. Rohman; M. Alfatun N.; E. Purwandari
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 2 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 2, August 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.052.01

Abstract

Hard Disk Drive (HDD) as a data storage device when operated with high temperatures (around 66oC), its function will be constrained. The CoFe alloys have a large coercivity field and can be patterned in very small sizes that are suitable for HDD devices. In this study, Co1-x Fex cube alloy was used (x = 0.25; 0.30; 0.50; 0.75). Samples were treated with temperature changes to get the Curie temperature. The coercivity field value is obtained by giving the external field and temperature below Curie temperature and also above Curie temperature to the samples. The VAMPIRE software is a micromagnetic simulation program based on atomistic models. The results showed that Curie’s temperature decreased when Co content increased. The composition of Co0.25 Fe0.75 has the highest Curie temperature that is equal to 1075 K. The temperature Curie is not affected by the size of the cube. When the sample is given a temperature rise below the Curie temperature, the value of the coercivity field decreases. The value of the coercivity field is very difficult to determine when the temperature used is above the Curie temperature. The percentage of composition does not affect the coercivity field value. Therefore, cube-shaped CoFe material is very suitable for use as a material data storage device operated at temperatures below the Curie.
Co-Authors E Supriyanto E. Purwandari Farid Thalib H.T.B.F Nagara L Rohman L. Rohman M. Alfatun N. Syahbuddin Tri Surawan Yunus Falah Kaban