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"Fabricate through-hole porous anodic aluminum oxide (AAO) template were made by a two-step anodization method of an aluminum with purity 99,98% in 0,3 M oxalic acid at 45 V with 360 minutes of second anodization time. The effect of duration time on the second anodizing step, voltage and solution of the electrolyte on the porous oxide layer and influence of the pore opening on the structural as a template were studied in detail. Then, the prepared template was used as a template for fabricated of dense array of Cu by using electrochemical deposition process performed by direct current (DC). The composition of AAO was confirmed by x-ray diffraction (XRD) analyses and for the deposition of Cu were performed by energy dispersive x-ray spectroscopy (EDS). The structural features of nanowire were calculated by scanning electron microscopy (SEM) images and compared with the imaging of AAO template as parameter.

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Fabrikasi templet Anodic aluminium Oxide (AAO) sebagai nanopori dilakukan dengan proses anodisasi dengan metode two-step anodization menggunakan alumunium dengan kemurnian 99,98 % pada larutan asam oksalat dengan konsentrasi 0,3 M pada voltase 45 V dan waktu anodisasi kedua sebesar 360 menit. Waktu anodisasi kedua dan voltase serta arus yang digunakan menjadi faktor utama dalam pembentukan ketebalan lapisan oksida dan diameter pori yang dihasilkan. Selain itu, pengaruh konsentrasi sangat berpengaruh dalam ketebalan templet AAO. Aplikasi templet AAO ini digunakan sebagai templet deposisi logam Cu, yaitu dengan cara elektrodeposisi dengan pada arus searah (DC). Digunakan pula X-ray diffraction (XRD) untuk melihat templet AAO dan komposisi Cu pada templet dikarakterisasi dengan energy dispersive x-ray spectroscopy. Untuk melihat morfologi nanopori pada cetakan AAO, dikarakterisasi dengan scanning electron microscopy (SEM)."

"Plasma Electrolytic Oxidation (PEO) merupakan pelapisan permukaan logam dengan plasma anodisasi untuk menghasilkan lapisan tahan karat dan keras. Sifat lapisan yang dihasilkan dikendalikan oleh parameter proses seperti arus dan waktu pembentukan. Proses PEO dilakukan dengan 2 variasi yaitu variasi waktu dan variasi arus dalam larutan 0,5 M Na3PO4. Pada variasi waktu, arus yang digunakan adalah 0,5 A dengan waktu 1, 3, dan 5 menit. Sedangkan pada variasi arus digunakan arus 0,2; 0,3; 0,4 A dan dilakukan pada waktu konstan selama 3 menit. Temperatur elektrolit dijaga tetap 30°C dan diaduk dengan magnetic stirrer dengan kecepatan konstan 300 rpm. Perubahan morfologi sebagai fungsi arus dan waktu diamati menggunakan scanning electron microscope dan energy dispersive X-ray spectroscopy (SEM-EDS). Analisis fasa dilakukan dengan X-ray Diffraction (XRD). Perubahan kekerasan diamati melalui uji kekerasan micro-Vickers. Perubahan sifat korosi diuji dengan metode electrochemical impedance spectroscopy (EIS) dan potentiodynamic polarization (PDP). Hasil karakterisasi menunjukkan fasa kristal yang terbentuk pada lapisan PEO adalah fasa Mg3(PO4)2 yang diidentifikasikan pada puncak 35°, 37°, 49° dan 62° pada pola XRD. Nilai kekerasan lapisan PEO yang terbentuk pada 1, 3 dan 5 menit masing-masing adalah 315,67; 427,67; dan 382,67 HV sedangkan pada arus 0,2; 0,3; dan 0,4 A diperoleh nilai kekerasan lapisan masing-masing sebesar 355; 421,67; dan 459 HV. Hasil uji polarisasi menunjukkan peningkatan ketahanan korosi yang ditunjukkan dengan berkurangnya rapat arus korosi. Semakin kecil rapat arus korosinya maka laju pembentukkan korosi semakin berkurang. Pada variasi waktu 1, 3 dan 5 menit nilai rapat arus korosinya adalah 3,24 x 10-5; 7,76 x 10-7; dan 1,11 x 10-6 A/cm2 sedangkan pada variasi arus 0,2; 0,3; dan 0,4 A nilai rapatarus korosinya adalah 2,26 x 10-6; 3,12 x 10-6; dan 7,60 x 10-7 A/cm2. Hasil EIS menunjukkan bahwa nilai R1 semakin besar yang artinya ketahanan resistansi polarisasi semakin besar dengan meningkatnya waktu dan arus pembentukan. Pada variasi waktu 1, 3 dan 5 menit nilai R1 adalah 42,35; 564,7; dan 574,4 Ω.cm2 sedangkan pada variasi arus 0,2; 0,3; dan 0,4A nilai R1 adalah 254,5; 169; 627,5 Ω.cm2 setelah dicelupkan selama 3 jam.

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Plasma Electrolytic Oxidation (PEO) is a coating for metal surface by plasma anodization to produce corrosion resistant and hard coating. The resulting coating properties were controlled by process parameters such as formation current and time. The PEO process in this research uses 2 variation: time and current formation in 0,5 M Na3PO4 solution. At the time variation, the current used is 0,5 A with time of 1, 3 and 5 minutes. Whereas in the current variation used 0,2;0,3 and 0,4 A for 3 minutes. The electrolyte temperature was kept at 30 oC and stirred with a magnetic stirrer at 300 rpm. Morphological changes were investigated by using scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS). Phase analysis was performed by X-ray Diffraction (XRD). Hardness changes were observed using micro-Vickers hardness test. Changes in corrosion properties were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). The phases formed in the PEO layer is Mg3(PO4)2 which identified at the peaks of 35°, 37°, 49° and 62° in the XRD pattern. Hardness of AZ31 alloys at 1, 3 and 5 minutes was 315,67 HV, 427,67 HV and 382,67 HV whilte at currents 0,2;0,3 and 0,4 A is 355 HV, 421,67 HV dan 459 HV. The polarization test results showed an increase in corrosion resistance which is approved by the reduced corrosion current density. The smaller the corrosion current, the rate of corrosion formation decreases. At the time variation of 1, 3 and 5 minutes the value of the corrosion current density is 3,24 x 10-5, 7,76 x 10-7, and 1,11 x 10-6 A/cm2 whereas in the variation of current 0,2; 0,3; and 0,4 A thecorrosion current density is 2,26 x 10-6; 3,12 x 10-6; and 7,60 x 10-7 A/cm2. EIS results showed that the higher value of R1 means the greater the polarization resistance. At the time variation of 1, 3 and 5 minutes the value of R1 are 42.35. 564.7, 574.4 Ω.cm2 whereas in the current variation of 0,2;0,3 and 0,4 A the value of R1 are 254.5, 169, 627.5 Ω.cm2 after being immersed for 3 hours."

"Nanoporous anodic aluminum oxide (AAO) layers were successfully fabricated on aluminum foil through an anodizing process in oxalic acid and mixed electrolytes of sulfuric and oxalic acid. The effect of electrolyte resistivity on the morphology of nanoporous AAO, such as pore diameter and pore density, was investigated. The nanoporous AAO layers‘bmorphology was examined using field emission scanning electron microscopy (FE-SEM) and analyzed using image analysis software. The results showed that anodizing in mixed electrolytes (sulfuric and oxalic acid) produced a much smaller pore diameter and a much higher pore density at lower voltage compared to anodizing in a single oxalic acid. For the anodizing process in oxalic acid, the pore diameters ranged from 14 to 52 nm, and the pore density ranged from 34?106 pores in 500×500 nm2. The anodizing process in the mixed electrolytes resulted in pore diameters within the range of 7?14 nm, and the pore densities were within the range of 211?779 pores in 500×500 nm2. Overall, increasing the electrolyte resistivity within the same solution leads to decreased pore diameter."

"The characteristics of coatings formed by Plasma Electrolytic Oxidation (PEO) are affected by the composition of metal substrates. In this work, the effect of alloying element Ca (0, 1 and 2 wt%) on the degradation behavior and apatite-forming ability of PEO coated AZ61 magnesium alloys was clarified by means of polarization measurements in 0.9% NaCl solution and an in-vitro test in Simulated Body Fluid (SBF), respectively. The AZ61 alloys were subjected to plasma electrolytic oxidation at a constant current of 200 A/m2 at 25°C for 8 min in 0.5 M Na3PO4 solution. The surface investigation suggested no significant effect of Ca content on the morphology of the PEO coating formed on the AZ61 specimens. The coatings exhibited an eruption-like structure decorated with micropores and microcracks. Their average thicknesses were 13.2, 17.4 and 14.3 µm for AZ61, AZ61-1Ca and AZ61-2Ca, respectively. The polarization measurements showed no significant difference in the corrosion potentials (-1.60 VAg/AgCl) and corrosion current densities (1.61×10-5 A cm-2) of all the coated specimens. Similarly, there was no significant effect of Ca on the apatite-forming ability in SBF, as indicated by the lack of apatite deposition on all the coated specimens after 14 days of immersion. Further sealing of the PEO coatings by chemical treatment in NaOH solution is suggested to enhance the corrosion resistance."

"Penumbuhan lapisan porous anodik aluminium oksida (PAAO) di atas substrat aluminium tubular merupakan suatu tantangan karena struktur pori tumbuh kurang teratur, kurang homogen, dan lapisannya rentan mengalami retakan. Penelitian ini bertujuan untuk meningkatkan ketahanan terhadap retakan lapisan PAAO yang ditumbuhkan di atas substrat aluminium tubular dengan penambahan etilen glikol (EG) dan pemanasan. Lapisan PAAO diperoleh melalui anodisasi aluminium dalam larutan 0,3 M asam sulfat dan oksalat pada suhu 10°C selama 4 jam. EG ditambahkan dengan variasi konsentrasi 0, 5, 10 dan15 vol%. Morfologi lapisan PAAO dikarakterisasi dengan FESEM dan struktur kristalnya dianalisis dengan XRD. Jumlah retakan berkurang dari 4,04x10-4/ µm2 menjadi 2,24x10-5/ µm2 retakan dan 2,47x10-4/µm2 menjadi 6,73x10-5/µm2 retakan dalam asam sulfat dan asam oksalat dengan penambahan 0-15 vol% EG. Rentang diameter pori sebelum dilepas dari substrat adalah 10-14 nm dan setelah dilepas dari substrat dan dietsa kimia menjadi 14-24 nm. EG berperan dalam menjaga stabilitas suhu selama anodisasi, mengurangi kerapatan arus dan meningkatkan viskositas larutan sehingga mampu mengurangi populasi dan lebar retakan. Pemanasan lapisan PAAO dari 1000-1250 oC menyebabkan perubahan fasa dari fasa amorf menjadi fasa kristal g, d, dan ὰ Al2O3.

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The growth of the porous anodic aluminum oxide (PAAO) layer on a tubular aluminum substrate is challenging because the pore structure grows less orderly, less homogeneous, and layers are prone to cracking. This study aims to improve resistance to cracking of PAAO layers grown on tubular aluminum substrates by adding ethylene glycol (EG) and heating. The PAAO layer was obtained by anodizing aluminum in a 0.3 M sulfuric and oxalic acid at 10 °C for 4 hours. The EG was added at various concentrations of 0, 5, 10, and 15 vol%. The morphology of PAAO layers was characterized by FESEM and the crystal structure was analyzed by XRD. The population of cracks decreased from 4.04x10-4/µm2 to 2.24x10-5/µm2 and 2.47x10-4/µm2 to 6.73x10-5/µm2 cracks in sulfuric and oxalic acid by addition EG 0-15 vol%. The pore diameter range before being removed from the substrate was 10-14 nm and after being removed from the substrate and chemically etched it was 14-24 nm. EG plays a role in maintaining temperature stability during anodization, reducing current, and increasing viscosity of solution to reduce population and width of the crack. Heating PAAO layer from 1000-1250 oC causes the phase change from amorphous to crystalline g-, d-, and ὰ-Al2O3."

"Aluminium merupakan salah satu logam yang banyak digunakan serta dikembangkan untuk berbagai aplikasi. Pada penelitian kali ini dilakukan modifikasi terhadap permukaan almunium meggunakan metode two step anodization sehingga pada permukaan almunium terbentuk almuniun oksida.Pembentukan anodic alumunium oxide AAO digunakan elektrolit asam oksalat 0.3 M dan elektrolit campuran asam oksalat dengan asam sulfat. Dilakukan variasi konsentrasi asam sulfat 0.1 M, 0.3 M dan 0.5 M yang ditambahkan kedalam asam oksalat untuk mendapatkan kondisi optimum. Kondisi optimum dalam pembentukan AAO dengan menggunakan elektrolit campuran asam oksalat 0.3 M dengan asam sulfat 0.1 M dengan diameter pori 76.32 nm dan jarak antar pori 33.56 nm. Variasi voltase dilakukan untuk mengetahui pengaruh voltase dalam pembentukan pori. Penggunaan voltase 45 V pada asam oksalat memperoleh diameter pori 97.37 nm dan jarak antar pori 30.97 nm, sedangkan pada elektrolit campuran asam oksalat 0,3 M dengan asam sulfat 0,1 M di peroleh diameter pori 76.32 nm dan jarak antar pori 33,55 nm hanya menggunakan voltase 25 V. Hal ini menunjukkan penambahan asam sulfat pada asam oksalat memberikan pengaruh terhadap voltase yang digunakan memberikan pengaruh dalam pembentukan templat anodic almunium oxide.

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Aluminum is one of the most widely used metals and developed for various applications. In this research, modification of aluminum surface using two step anodization method and aluminum oxide has formed on aluminum surface. The forming of anodic aluminum oxide AAO is used electrolyte oxalic acid 0.3 M and electrolyte mixture of oxalic acid and sulfuric acid. A variation of 0.1 M, 0.3 M and 0.5 M sulfuric acid concentrations was added to the oxalic acid to obtain the optimum condition. The optimum conditions in the forming of AAO by using 0.3 M electrolyte oxalic acid and 0.1 M sulfuric acid with pore diameter 76.32 nm and pore distance 33.56 nm. Variations of voltage are performed to determine the effect of voltage in the pore forming. Using 45 V voltage on oxalic acid obtained pore diameter 97.37 nm and pore distance 30.97 nm, whereas in the mixing of electrolyte oxalic acid 0,3 M and sulfuric acid 0,1 M obtained pore diameter 76.32 nm and pore distance 33.55 nm. This shows that the addition of sulfuric acid to oxalic acid has a significant effect on the voltage used."