Analisis Pengaruh Waktu Sputtering Pd dan Ni pada Sintesis Material Elektrokatalis Berbahan Pd-Ni/Graphene terhadap Unjuk Kerja Direct Methanol Fuel Cell (DMFC)

Direct Methanol Fuel Cell (DMFC) memiliki potensi untuk dikembangkan dengan menambahkan graphene sebagai material pendukung katalisnya karena luas permukaannya yang tinggi. Kemudian kinerjanya juga dapat ditingkatkan dengan penambahan logam yang sesuai seperti Nikel. Tujuan penelitian ini ialah menganalisa pengaruh waktu sputtering pada sintesis material elektrokatalis berbahan graphene/Pd-Ni terhadap unjuk kerja DMFC. Graphene diperoleh dari grafit yang dioksidasi menggunakan metode Hummer kemudian direduksi dengan serbuk Zn dan proses hidrotermal selama 12 jam pada temperatur 160oC. Kemudian didepositkan pada carbon cloth lalu dilapisi dengan logam Pd dan/atau Ni selama 15, 10 dan 5 menit dengan metode radio-frequency sputtering. Hasil penelitian menunjukkan waktu sputtering Pd(10) dan Pd(15)-Ni(5) memberikan hasil terbaik dengan nilai kapasitansi spesifik 32,86 F/g dan 23,30 F/g, Electrochemical active surface area (ECSA) sebesar 0,747 m2/g dan 0,371 m2/g berdasarkan pengujian cyclic voltametry (CV) pada larutan KOH 1M. Sedangkan pengujian pada elektrolit KOH+CH3OH 1M menghasilkan rasio If/Ib 23,5 dan 47,36 serta densitas arus sebesar 4,80 mA/g dan 4,18 mA/g

Deposition of Titanium Aluminium Nitride Thin Layer on High Speed Steel Substrate by Radio Frequency Sputtering

High Speed Steel (HSS) has been widely used in manufacturing industry as one of cutting tool materials because of its good mechanical properties yet with a low price. However, since this material has a low thermal resistance property, it will limit its application when used in dry cutting process. Several methods have been used to improve the cutting performance of HSS in dry cutting. One of them was by growing a thin layer of hard coating on the contact surface of the cutting tool material. In this research, Titanium Aluminium Nitride layer were deposited on AISI M41 High Speed Steel substrate by using Radio Frequency (RF) Sputtering method. The aims of this study were to analyze the effect of variations of Aluminium surface area ratios (10, 20, 30, and 40 %) on the Titanium target and also to analyze the effect of deposition time (15, 30, and 45 minutes) on the composition, phase characterization and morphology of the thin layer that formed. The formation of TiAlN and AlN crystalline compounds were observed by X-Ray Diffraction method. A dense layer with a thickness range from 1.4 to 5.2 µm was observed by using a Scanning Electron Microscopy. It was known that the deposition time affect the thickness and also the roughness of the layer. The topography images by Atomic Force Microscopy showed that the deposition time of 45 minutes produce the finest layer with the surface roughness of 10.8 nm