Wisnu Ari Adi
Pusat Sains dan Teknologi Bahan Maju, Badan Tenaga Nuklir Nasional

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Effect of Silica Composition from Rice Husk Ash on The Performace of Absorbing Electromagnetic Wave on Composite of Unsaturated Polyester Resins/Silica Rizky Fauzy; Wisnu Ari Adi; Yana Taryana; Y. Yusmaniar
Jurnal ILMU DASAR Vol 19 No 1 (2018)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2353.719 KB) | DOI: 10.19184/jid.v19i1.6336

Abstract

This study aim is to know the effect of silica composition on the absorption of electromagnetic waves in the composite of unsaturated polyester resins (UPR)/silica. Silica raw materials have been synthesized from the results of rice husk ash extraction. The results of the analysis phase and elementary respective using X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) show that the extraction of silica has an amorphous phase with a high purity. This silica powders are filler material acts as an electromagnetic waves absorber material and combined with the UPR as a matrix to form a composite. Silica powder varied with several compositions in this composite. The observation of scanning electron microscope (SEM) shows that the silica particles have been distributed evenly in the UPR matrix. Meanwhile the results of testing the absorption of electromagnetic waves at frequency range of 8 GHz - 12 GHz using a vector network analyzer (VNA) show that the addition of silica composition have significant effect on the absorption of electromagnetic waves. The more the silica content in the UPR matrix causes the absorption of electromagnetic waves more increasing. It was concluded that the presence of silica can improve the absorption performance of electromagnetic waves in composite UPR/silica. Keywords: rice husk ash, silica, UPR, composites, electromagnetic wave absorber
Pengaruh Waktu Milling Terhadap Mikrostruktur dan Sifat Magnetik Komposit NiFe2O4-NdFeO3 [Influence Of Milling Time on Microstructure and Magnetic Properties of NiFe2O4-NdFeO3 Composite] Ade Mulyawan; Yunasfi Yunasfi; Wisnu Ari Adi
Metalurgi Vol 32, No 3 (2017): Metalurgi Vol. 32 No. 3 Desember 2017
Publisher : National Research and Innovation Agency (BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1021.118 KB) | DOI: 10.14203/metalurgi.v32i3.216

Abstract

The development of electromagnetic wave and microwave absorbing materials was important to overcome the electromagnetic wave interference in communication technology and in the development of radar materials for military purposes. In this study the composite which contained two different phases of NiFe2O4-NdFeO3 has successfully synthesized using Fe2O3, NiO, and Nd2O3 as starting materials through solid state reaction method. The composites were made by varying milling times from 10, 15, 20, and 25 hours then followed by sintering process at 1200 °C for 3 hours. Phase identification was performed using XRD (x-ray diffractometer) which revealed only NiFe2O4 and NdFeO3 phases. The crystallite size of the NiFe2O4 phase is in the range of 59-68 nm, and NdFeO3in the range of 62-65 nm. The agglomeration of particles was observed by using SEM (scanning electron microscope). Referring to the characterization result of the magnetic properties by using VSM (vibrating sample magnetometer), it is known that the parameters of the magnetic properties such as magnetization saturation (Ms), magnetization remanence (Mr), and coercivity (Hc) are highly dependent on the mass fraction, crystallite size,and the homogenity of the phase composition.AbstrakPengembangan bahan penyerap gelombang elektromagnetik dan gelombang mikro sangat penting dilakukan untuk mengatasi masalah interferensi gelombang elektromagnetik pada teknologi komunikasi serta pada material radar untuk tujuan militer. Pada penelitian ini berhasil dilakukan pembuatan material penyerap gelombang elektromagnetik komposit fasa NiFe2O4-NdFeO3 dengan menggunakan Fe2O3, NiO, dan Nd2O3 melalui reaksi padatan. Sampel komposit dimilling dengan variasi waktu 10, 15, 20, dan 25 jam dan selanjutnya disinter pada suhu 1200 oC selama 3 jam. Identifikasi fasa dilakukan dengan X-ray Diffractometer (XRD) menunjukan bahwa komposit hanya terdiri dari fasa NiFe2O4 dan NdFeO3. Ukuran kristalit fasa NiFe2O4 berada pada kisaran 59-68 nm, sedangkan fasa NdFeO3 pada kisaran 62-65 nm. Pengamatan morfologi permukaan dilakukan menggunakan Scanning Electron Microscope (SEM). Berdasarkan nilai parameter sifat magnetik yang dihasilkan menggunakan Vibrating Sample Magnetometer (VSM) seperti magnetisasi saturasi(Ms), magnetisasi remanen (Mr), dan koesivitas (Hc) sangat bergantung pada fraksi massa, ukuran kristalit, dan homogenitas fasa yang terbentuk.