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All Journal TEKNIK Teknologi Indonesia Metalurgi Piston: Journal of Technical Engineering Jurnal Litbang Polri Jurnal Sains Materi Indonesia
Gadang Priyotomo
Research Center for Metallurgy and Material, Indonesian Institute of Sciences, Serpong, Tangerang
Aerospace Engineering Computer Science & IT Control & Systems Engineering Energy Engineering Industrial & Manufacturing Engineering Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mechanical Engineering Social Sciences

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THE INFLUENCES OF APPLIED STRESS, TEST TEMPERATURE AND CONCENTRATION ON ENVIRONMENT INDUCED CRACKING OF Ni3(Si,Ti) INTERMETALIC COMPOUND IN NEUTRAL SODIUM CHLORIDE SOLUTIONS priyotomo, gadang
Teknologi Indonesia Vol 38, No 1 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (16.054 KB) | DOI: 10.14203/jti.v38i1.133

Abstract

The environment-induced cracking (EIC) behavior of Ni3(Si,Ti) intermetallic compound was investigated as the function of applied stress, test temperature, and chloride-ion concentration in NaCl solution using a constant load method. From the applied stress dependence of the three parameters ( tf, lss and tss/tf ), the relationships were found to be divided into three regions: stress, EIC, and corrosion dominated regions. The ratio of tss/tf in the EICdominated region was independent constant of applied stress, test temperature, and chloride-ion concentration. Furthermore, the relationship between log tf and log lss in the EIC-dominated region became a good straight line, irrespective of applied stress, test temperature, and chloride-ion concentration. The fracture appearance in the EIC dominated region was intergranular. On the basis of the results obtained, an intergranular EIC was supposed to be influenced by hydrogen entry, dissolution, and film formation.
Studi Inhibitor Korosi Berbasis Imidazoline Salt Pada Brine Water Di Pipa Penyalur Minyak Mentah [Studies of Imidazoline Salt Inhibitor for Brine Water in Crude Oil Pipeline] Nuraini, Lutviasari; Priyotomo, Gadang; Nasoetion, Ronald; Harsisto, Harsisto
Metalurgi Vol 31, No 2 (2016): Metalurgi Vol. 31 No. 2 Agustus 2016
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (371.431 KB) | DOI: 10.14203/metalurgi.v31i2.62

Abstract

A study of imidazoline salt inhibitor for brine water in crude oil pipeline was carried out using tafel polarization test, Fourier Transform Infrared Spectroscopy (FTIR) and Electrochemical Impedance Spectroscopy (EIS). A type of specimen used in this research is API 5L grade B. The solution of brine water came from fluid in crude oil pipeline. The addition of commercial inhibitor of imidazoline salt base was conducted with range of 3-40 ppm for polarization test and range of 3-20 ppm for EIS test. The addition of imidazoline salt at 3-20 ppm is effective to decrease corrosion rate and to increase inhibitor efficiency up to 95% . The resistance of adsorbed molecule layer increase with the addition of inhibitor compared without inhibitor, where this addition could decrease the electrochemical reaction on the surface. The decrease of corrosion rate took place due to the presence of adsorbed thin layer in metal surface.AbstrakStudi kinerja inhibitor imidazoline salt pada brine water di pipa penyalur minyak mentah dilakukandengan melakukan pengujian tafel, Fourier Transform Infrared Spectroscopy (FTIR) dan Electrochemical Impedance Spectroscopy (EIS). Jenis spesimen uji baja yang digunakan dalam penelitian adalah API 5L dan larutan brine water berasal dari 70% dari total fluida di pipa penyalur minyak mentah. Penambahan inhibitor komersial berbasis imidazoline salt dilakukan dengan variasi 3 - 40 ppm untuk pengujian polarisasi dan variasi 3 - 20 ppm untuk pengujian EIS. Penambahan inhibitor berbasis imidazoline salt antara 3 – 20 ppm secara efektif dapat menurunkan nilai laju korosi dan meningkatkan efisiensi inhibitor hingga 95%. Tahanan lapisan adsorpsi molekul dengan penambahan inhibitor meningkat dibandingkan kondisi tanpa inhibitor, dimana hal ini dapat menurunkan aktifitas reaksi elektrokimia di permukaan baja. Penurunan laju korosi terjadi dikarenakan pembentukan lapisan tipis yang teradsopsi di permukaan logam.
Sifat Korosi Dari Material Berbasis Nb yang Mengandung 24% Berat Sn Pada Berbagai Konsentrasi Natrium Klorida [Corrosion Behavior Of Nb-Base Material Containing 24wt% Sn At Various Sodium Chloride Concentrations] Priyotomo, Gadang
Metalurgi Vol 30, No 1 (2015): Metalurgi Vol.30 No.1 APRIL 2015
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (473.032 KB) | DOI: 10.14203/metalurgi.v30i1.104

Abstract

Sifat korosi pada material berbasis Nb yang berisi 24% berat Sn yang terdiri dari fasa Nb3Sn dan NbSn2 telah diinvestigasi dengan menggunakan pengujian polarisasi, potensiostatik dan  metode analisis permukaan (SEM dan EDS) di dalam larutan netral NaCl. Pelarutan terseleksi pada fasa NbSn2  terjadi dengan konsentrasi rendah pada Nb dibandingkan dengan fasa Nb3Sn.  Melalui kurva polarisasi, rapat arus korosi dan laju korosi pada material meningkat dengan peningkatan konsentrasi klorida.   Pada daerah pasif, pelarutan terseleksi tidak terjadi pada dua fasa yang ada, namun pelarutan tersebut terjadi di daerah transpasif. Peningkatan konsentrasi klorida memberikan efek mengganggu terhadap ketahanan korosi pada material. Hasil yang didapat juga menjelaskan efek galvanik antara fasa-fasa yang menyebabkan kelarutan terseleksi pada fasa NbSn2. AbstractThe corrosion behavior of Nb-base material containing 24wt% Snthat are consisted of Nb3Sn and NbSn2phases, has been investigated using polarization test, potentiostatic test and surface analytical method (SEM;scanning electron microscope and EDS; Energy Dispersive Spectroscopy) in neutral NaClsolutions. It wasfound that the preferential dissolution of NbSn2 phase with a lower Nb concentration compared to Nb3Snphase. From polarization curves, the corrosion current density and corrosion rate of the material increasewith the increase of chloride concentration. In passive region, there is no preferential dissolution in both thephases, whereas the preferential dissolution of NbSn2 takes place in transpassive region. The increase ofchloride concentration has detrimental effect in the corrosion resistance of the material. The results obtainedwere also explained the galvanic effect between the phases generating for the preferential dissolution ofNbSn2 phase.
Pengaruh Penambahan Inhibitor Ekstrak Tembakau Terhadap Laju Korosi Internal Pipa API 5L X-52 Pada Artificial Brine Water Dengan Injeksi Gas CO2 [Effect of Addition of Extracted Tobacco Inhibitor to The Corrosion Rate of Internal Steel Pipe API 5L X-52 in Artificial Brine Water With CO2 Gas Injection] Ahmadi, Rapli Nur; Oediyani, Soesaptri; Priyotomo, Gadang
Metalurgi Vol 31, No 3 (2016): Metalurgi Vol. 31 No. 3 Desember 2016
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (827.178 KB) | DOI: 10.14203/metalurgi.v31i3.164

Abstract

Crude oil containing brine water with high concentration of NaCl and HCO3 and the presence of dissolved CO2 gas may increase the potential for corrosion in the pipeline. The use of natural corrosion inhibitor is one of the alternative to solve these problem. Natural materials were chosen as an alternative because it is safe, readily available, biodegradable, low cost, and environmentally friendly. This study was conducted to determine the effect of tobacco extracts on the rate of corrosion and inhibition efficiency. The novelty of this research is a continuous injection of CO2 gas that does not exist in previous research. Spectroscopy analysis was conducted to determine the chemical composition of samples of steel API 5L X-52, TLC densitometry was used to determine the levels of nicotine in tobacco sauce. Gamry Potensiostat Type 6:25 was used for testing the corrosion behavior, using the Tafel polarization and EIS methods. The results show that, the corrosion rate of samples decreased with the addition of tobacco extracts. The addition of 60 ppm of tobacco extract in a solution decrease corrosion rate samples at 8.95 mpy in ABW 1 and 9.87 mpy in ABW 2. Optimum inhibition efficiency occurs upon the addition of 60 ppm tobacco extracts, for the solution of ABW 1 by 79.51% and amounted to 80.94% ABW 2. The inhibition efficiency began to decline by the addition of 80 ppm, to 42.32% in ABW 1 by and 68.71% in ABW 2.AbstrakCrude oil yang mengandung brine water dengan kadar NaCl dan HCO3 - yang tinggi serta adanya gas CO2 yang terlarut dapat meningkatkan potensi korosi pada pipa. Penggunaan inhibitor korosi alami menjadi alternatif baru untuk menyelesaikan masalah tersebut. Bahan alam dipilih sebagai alternatif karena bersifat aman, mudah didapatkan, bersifat biodegradable, biaya murah, dan ramah lingkungan. Penelitian ini dilakukan untuk mengetahui pengaruh penambahan ekstrak tembakau terhadap laju korosi dan efisiensi inhibisi yang dihasilkan dengan menambahkan pembaharuan penelitian berupa penginjeksian gas CO2 secara kontinu yang belum ada pada penelitian sebelumnya. Pengujian pada penelitian ini menggunakan spectroscopy untuk mengetahui komposisi kimia sampel baja API 5L X-52, TLC. Densitometri digunakan untuk mengetahui kadar nikotin pada sampel tembakau. Gamry Potensiostat Type 6.25 digunakan untuk pengujian polarisasi Tafel dan EIS. Hasil penelitian menunjukkan bahwa data laju korosi baja API 5L X-52 mengalami penurunan dengan penambahan ekstrak tembakau. Penurunan optimum laju korosi terjadi pada penambahan 60 ppm ekstrak tembakau pada larutan ABW 1 sebesar 8,95 mpy dan ABW 2 sebesar 9,87 mpy. Peningkatan optimum efisiensi inhibisi terjadi pada penambahan 60 ppm ekstrak tembakau, untuk larutan ABW 1 sebesar 79,51% dan ABW 2 sebesar 80,94%. Efisiensi inhibisi mulai mengalami penurunan kembali pada penambahan 80 ppm, untuk larutan ABW 1 sebesar 42,32% dan ABW 2 sebesar 68,71%. 
Studi Korosi Baja Galvanis Melalui Perlakuan Ekspos Di Lingkungan Perairan Sungai Cidaho - Sukabumi Royani, Ahmad; Priyotomo, Gadang; Gunawan, Hadi; Triwardono, Joko; Nuraini, Lutviasari; Prifiharni, Siska; Nugraha, Heri; Sugiarti, Sugiarti; Sundjono, Sundjono
TEKNIK Vol 41, No. 1 (2020): May 2020
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (288.12 KB) | DOI: 10.14710/teknik.v41i1.24709

Abstract

Penelitian ini bertujuan untuk mempelajari korosi pada baja galvanis setelah diekspos di Sungai Cidaho Wilayah Sukabumi, Jawa Barat. Kehilangan berat baja galvanis diukur dengan metode pengurangan berat setelah diekspos untuk periode waktu tertentu di permukaan air sungai dan kedalaman air 1 meter. Morfologi permukaan dan komposisi produk korosinya dianalisismenggunakan Scanning Electron Microscopy (SEM) - Energy Dispersive Spectroscopy (EDS) dan X-Raya Diffraction (XRD). Setelah diekspos, seluruh permukaan baja galvanis tertutup oleh produk korosi. Hasil berat yang hilang dari baja galvanis setelah diekspos 76 hari adalah 1,37 mg/cm2 pada permukaan air sungai dan 7,83 mg/cm2 untuk kedalaman air 1 meter. Peningkatan kerusakan dari baja galvanis ini terjadi karena tidak terbentuk lapisan protektif akibat tergerus arus sungai. Produk korosi yang dominan pada baja galvanis yang diekspos pada kedalaman 1 meter adalah senyawa Zincite (ZnO). Hasil ini mengindikasikan bahwa penggunaan baja galvanis tidak cocok untuk lingkungan di kedalaman air
Efek Perlakuan Panas Terhadap Sifat Mekanik Logam Stainless Steel Seri J4 Priyotomo, Gadang; Astawa, I Nyoman Gede Putrayasa; Rokhmanto, Fendy
TEKNIK Vol. 42, No. 2 (2021): August 2021
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/teknik.v42i2.36461

Abstract

Logam stainless steel (SS) seri J4 merupakan baja paduan austenitik krom dan mangan yang mempunyai kekuatan dan ketahanan korosi yang cukup baik. Namun umumnya, logam SS austenitik mengalami proses sensitasi saat terjadi pemanasan logam yang menurunkan sifat mekanik logam. Investigasi pengaruh sifat mekanik SS seri J4 terhadap variasi temperatur logam  dilakukan menggunakan uji tarik dan uji kekerasan mikro Vickers. Proses pemanasan logam dilakukan pada rentang suhu antara 600oC-1050oC. Penurunan nilai kekuatan tarik, kekuatan luluh, dan kekerasan yang disertai kenaikan ketangguhan dan elongasi terjadi seiring dengan kenaikan temperatur logam hingga 1050oC. Ini dimungkinkan akibat transformasi α’-martensite menjadi fasa austenit seiring dengan peningkatan temperatur pemanasan. Disisi lain, Penurunan nilai ketangguhan, kekuatan luluh dan elongasi terjadi pada kisaran temperatur pemanasan 700oC dimana ini mengindikasikan proses sensitasi paduan stainless steel J4 terjadi. Proses sensitasi logam SS akan berhubungan dengan kerentanan korosi retak tegang stainless steel.
Copper Dissolution Rate of Modified Self-Polishing Antifouling Paint with Cerium Oxide Nikitasari, Arini; Irawan, Januar; Priyotomo, Gadang; J.W. Soedarsono; Riastuti, Rini
Jurnal Sains Materi Indonesia Vol. 26 No. 2 (2025): Jurnal Sains dan Materi Indonesia
Publisher : BRIN Publishing (Penerbit BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/jsmi.2025.8753

Abstract

The main objective of the work is to substitute SeaNine 211 in self-polishing antifouling (SPA) paint formulations for marine coating using cerium oxide as a co-biocide. The development of SPA paint with cerium oxide as a co-biocide is expected to significantly improve the environmental friendliness and efficacy of antifouling paints. The preparation of modified SPA paint was undertaken by incorporating the cerium oxide with various concentrations (0.1, 0.3, and 0.5 wt.%) in the SPA paint formulation without SeaNine 211. The copper dissolution rate determines the efficacy of antifouling paint, where the greater the copper release rate, the greater the efficacy of the antifouling paint. The leached-out test results obtained suggest that with an increase of 0.1% wt in the concentration of cerium oxide, there was an improvement in the copper dissolution rate. It was also observed that the mild steel specimens were coated with modified SPA paint when immersed in the seawater for 7 days for testing. The properties were observed by utilizing scanning electron microscopy (SEM). An improvement in the copper dissolution rate was found, as shown by cerium oxide SPA paint when contrasted with bare paint. The contact angle test finding also suggests that adding 0.1% wt of cerium oxide to the SPA paint will increase the dissolution rate of copper. This work could provide insight into developing an environmentally friendly antifouling paint co-biocide.
Evaluasi Mutu Sarana dan Prasarana Polri untuk Pengamanan Objek Vital dalam Rangka Pengamanan Pemilu 2024: Pengamanan Objek Vital dalam Rangka Pengamanan Pemilu 2024 Raslin, Harvin; Astuti, Septi; Saragih, Agung Shamsudin; Wahyono, Ary; Priyotomo, Gadang
Jurnal Litbang Polri Vol 27 No 2 (2024): JURNAL LITBANG POLRI
Publisher : Pusat Penelitian dan Pengembangan Polri

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46976/litbangpolri.v27i2.247

Abstract

The Directorate of Vital Object Security (Ditpamobvit) of the Indonesian National Police is responsible for securing vital objects by applying predictive policing techniques to anticipate and analyze issues that could potentially disrupt public security. As the 2024 elections approach, readiness for securing vital objects becomes crucial to preempt potential security disturbances. This study aims to analyze the preparedness of facilities and infrastructure in supporting the performance of Ditpamobvit. The methodology employed is descriptive-analytical with both qualitative and quantitative approaches, using interviews, observations, checklists, and questionnaires. The results indicate that Pamobvit facilities at the Polda level are generally adequate and function well according to regional needs, whereas at the Polres level, they are still limited. Regular training is necessary to enhance personnel knowledge, storage facilities are available but not yet sufficient, and skill improvement is undertaken through both internal and external training. However, high-tech training needs to be optimized, training for modern facilities ceases after contract periods, maintenance costs lack standard indices at SBK Polri, there is no budget support for operator welfare, new facilities do not keep up with the increase in vital objects, personnel understanding of incident handling is limited, and there is a lack of special storage space. Required solutions include optimizing high-tech training, extending training for modern facilities, establishing maintenance cost norms, securing budget support for operator welfare, planning new facility procurement, improving understanding through simulations, and providing accessible standard operation guides.
The Effect of Chloride Ions for Corrosion Resistance of C276 Material in NaCl Solution Priyotomo, Gadang; Anam, Ahsonul
Piston: Journal of Technical Engineering Vol. 8 No. 1 (2024)
Publisher : Program Studi Teknik Mesin Universitas Pamulang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32493/pjte.v8i1.48481

Abstract

Hastealloy-C276 is an austenitic nickel-molybdenum-chromium alloy with small amounts of tungsten added. This material is quite familiar and is used in various industrial components. However, this alloy, like other types, is very susceptible to corrosion due to the influence of chloride ions in solution. The corrosion resistance of steel alloy materials was investigated using electrochemical methods including open circuit potential (OCP), Anodic Potentiodyamic (AP) with and Tafel in NaCl solution media. The test parameters carried out were chloride concentration (0.001 M-1M) and pH (2, 7 and 10) values. The test results show that an increase in chloride ion concentration causes a decrease in the OCP value in a negative direction, which indicates a tendency for decreasing of the corrosion resistance for C276. The AP test results show that the pitting potential (Epit) value slowly decreases as the chloride ion concentration increases up to 1 M. On the other hand, the role of pH is very important in changing the corrosion resistance performance. A decrease in pH to 2 causes an increase in the corrosion rate of the material, whereas an increase in pH causes this decrease.
The Influence of Chloride Ion Concentration and Short Immersion Time on the Corrosion Behavior of C11000 Copper Alloy Priyotomo, Gadang; Anam, Ahsonul; Maldini, Noviar Rizky
Piston: Journal of Technical Engineering Vol. 8 No. 2 (2025)
Publisher : Program Studi Teknik Mesin Universitas Pamulang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32493/pjte.v8i2.48881

Abstract

The effect of various chloride ion concentration (0 %, 1 %, 2 %, 3%, 4% and 5 % NaCl solution) on the corrosion behavior of the C1100 copper alloy was investigated with the immersion test (weight loss method). The effect of various immersion periods was also examined up to 14 days. After conducting immersion test, metal surfaces were observed with an optical microscope and the SEM analysis. The product of corroded copper was characterized using Energy Dispersive Analysis of X-rays (EDAX). On the basis of results, the magnitude of corrosion rate is higher in increasing the chloride concentration and immersion period, respectively. The increase of chloride concentration causes the copper oxide layer to become porous and cracked compared to without chloride addition. The reduction in the integrity of the copper protective layer took place due the presence of chloride ion.
Co-Authors Ahmadi, Rapli Nur ahsonul anam Astawa, I Nyoman Gede Putrayasa Astuti, Septi Fachry Abda El Rahman Hadi Gunawan, Hadi Harsisto, Harsisto Heri Nugraha Irawan, Januar J.W. Soedarsono Maldini, Noviar Rizky Nasoetion, Ronald Nikitasari, Arini Nuraini, Lutviasari Nuraini, Lutviasari Prifiharni, Siska Raslin, Harvin Rini Riastuti, Rini Rokhmanto, Fendy Royani, Ahmad Saragih, Agung Shamsudin Soesaptri Oediyani Sundjono, Sundjono Triwardono, Joko Wahyono, Ary