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"Peningkatan kebutuhan bahan penghambat korosi yang aman dan ramah lingkungan menjadi perhatian utama, terutama dalam industri berbasis baja karbon rendah. Salah satu penyebab utama kerusakan pada material ini adalah korosi yang dipercepat oleh penggunaan larutan asam seperti H2SO4. Salah satu cara untuk mengurangi laju korosi dari material adalah dengan menambahkan inhibitor organik dari ekstrak tumbuhan yang mengandung senyawa bioaktif. Pada penelitian ini, dilakukan penambahan variasi konsentrasi inhibitor dari ekstrak akar pepaya (Carica papaya L.) dengan melarutkan ke dalam larutan 1M asam sulfat (H2SO4), dimana asam sulfat merupakan senyawa yang digunakan untuk acid pickling pada baja. Dilakukan uji Optical Emission Spectroscopy (OES) untuk mengetahui komposisi kimia dari material uji sesuai dengan spesifikasi material API 5L dan uji Fourier Transform Infra Red (FTIR) untuk mengetahui senyawa yang terkandung dalam ekstrak akar pepaya yang akan digunakan sebagai inhibitor pada baja karbon rendah API 5L grade B. Dilakukan juga pengujian Linear polarisasi untuk mengetahui efisiensi laju korosi pada penambahan variasi ekstrak inhibitor akar pepaya. Kemudian, dilakukan pengujian Electrochemical impedance spectroscopy (EIS) untuk menginterpretasikan sistem variasi konsentrasi inhibitor akar pepaya pada rangkaian listrik. Hasil pengujian menunjukkan bahwa material uji sesuai dengan spesifikasi API 5L grade B, ekstrak akar pepaya mengandung senyawa bio aktif flavonoid, saponin, alkaloid, dan tanin yang terbukti menurunkan laju korosi dengan variasi konsentrasi dari 4 ml sampai 20 ml terbukti menurunkan laju korosi dari 1,172 mm/year menjadi 0,074 mm/year dengan efisiensi maksimum 93,68% pada konsentrasi 20 ml.

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The increasing need for safe and environmentally friendly corrosion inhibiting materials is a major concern, especially in low carbon steel-based industries. One of the main causes of damage to these materials is accelerated corrosion by the use of acidic solutions such as H2SO4. One way to reduce the corrosion rate of the material is to add organic inhibitors from plant extracts containing bioactive compounds. In this study, the addition of various concentrations of inhibitors from Akar Pepaya extract (Carica papaya L.) was carried out by dissolving it in 1M sulfuric acid (H2SO4) solution, where sulfuric acid is a compound used for acid pickling on steel. Optical Emission Spectroscopy (OES) test was conducted to determine the chemical composition of the test material in accordance with API 5L material specifications and Fourier Transform Infra Red (FTIR) test to determine the compounds contained in Akar Pepaya extract which will be used as an inhibitor on API 5L grade B low carbon steel. Linear polarization testing was also carried out to determine the efficiency of the corrosion rate in the addition of akar pepaya inhibitor extract variations. Then, Electrochemical impedance spectroscopy (EIS) testing was carried out to interpret the system of variations in Akar Pepaya inhibitor concentration in electrical circuits. The test results show that the test material is in accordance with API 5L grade B specifications, Akar Pepaya extract contains bioactive compounds flavonoids, saponins, alkaloids, and tannins which are proven to reduce the corrosion rate with a concentration variation from 4 ml to 20 ml which is proven to reduce the corrosion rate from 1,172 mm/year to 0,074 mm/year with a maximum efficiency of 93,68% at a concentration of 20 ml."

"Baja rendah karbon merupakan bahan konstruksi utama pada industri minyak dan gas. Namun, bahan ini bersifat sangat rentan terhadap korosi. Pada penelitian ini, telah dilakukan sintesis inhibitor korosi TETA-MGS (trietilentetramin-minyak goreng sawit) dengan metode refluks selama 14 jam. Temperatur divariasikan pada 130, 140, 150, dan 160⁰C, dan kecepatan pengadukan pada 700, 1000, dan 1200 rpm. Diperoleh kondisi reaksi optimum dari titrasi penentuan angka penyabunan, yaitu pada temperatur 150⁰C, kecepatan pengadukan 1200 rpm, dan waktu reaksi 14 jam. Produk sintesis TETA-MGS A dimurnikan, sehingga didapatkan TETA-MGS B. TETA-MGS B kemudian diidentifikasi dengan KLT, dikarakterisasi dengan spektrofotometri UV-visibel, spektroskopi FTIR dan LC-MS. Identifikasi dengan KLT menunjukkan bahwa TETA-MGS B bersifat cukup polar seperti prekursor trietilentetraminnya. TETA-MGS B memberikan serapan maksimum pada 204 nm untuk spektrum UV-visibelnya  dan memiliki gugus-gugus kromofor yang sama dengan minyak goreng sawit dan trietilentetramin. Spektrum FTIR TETA-MGS B menunjukkan adanya tumpang tindih senyawa-senyawa TETA-MGS B. Pada LC-MS, diketahui bahwa TETA-MGS B dari sintesis pada 150⁰C, 1200 rpm, dan selama 14 jam bukan senyawa imidazolin, melainkan masih berupa intermediet amidanya. Senyawa imidazolin baru diperoleh pada temperatur sintesis 160⁰C. Pengujian efisiensi inhibisi korosi dilakukan dengan metode gravimetri dan elektrokimia menggunakan TETA-MGS A dan B dari sintesis pada 150⁰C, 1200 rpm, dan selama 14 jam. Konsentrasi divariasikan pada 0, 5, 20, 50, dan 100 ppm. Pengujian dilakukan untuk baja rendah karbon JIS G3123 grade SGD 400D pada media korosi berupa larutan NaCl 1,5% yang telah dialirkan gas CO2. Efisiensi tertinggi diperoleh pada konsentrasi 100 ppm dan nilainya 62,12 dan 93,52% untuk TETA-MGS A dan B masing-masing. Hasil SEM-EDX mendukung efisiensi tinggi TETA-MGS B. Tipe korosi yang terjadi adalah korosi pitting. Adsorpsi TETA-MGS B pada permukaan baja merupakan fisisorpsi kuat dan sesuai dengan model isoterm Langmuir.

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Low carbon steel is the main construction material in the oil and gas industry. However, this material is highly susceptible to corrosion. In this research, the synthesis of the corrosion inhibitor TETA-PCO (triethylenetetramin-palm cooking oil) was carried out using the reflux method for 14 hours. The temperature was varied at 130, 140, 150 and 160⁰C, and the stirring speed at 700, 1000 and 1200 rpm. The optimum reaction conditions were obtained from saponification value determination titration, namely at a temperature of 150⁰C, a stirring speed of 1200 rpm, and a reaction time of 14 hours. The synthesis product of  TETA-PCO A was purified to obtain TETA-PCO B. TETA-PCO B was then identified by TLC, characterized by UV-visible spectrophotometry, FTIR spectroscopy and LC-MS. Identification by TLC showed that TETA-PCO B is as polar as its precursor triethylenetetramine. TETA-PCO B provides maximum absorption at 204 nm for its UV-visible spectrum and has the same chromophore groups as palm cooking oil and triethylenetetramine. The FTIR spectrum of TETA-PCO B showed an overlapping of the TETA-PCO B compounds. In LC-MS, it was found that TETA-PCO B from synthesis at 150⁰C, 1200 rpm, and for 14 hours was not an imidazoline compound, but were still its amide intermediates. Imidazoline compounds were obtained at a synthesis temperature of 160⁰C. Corrosion inhibition efficiency testing was carried out by gravimetric and electrochemical methods using TETA-PCO A and B from synthesis at 150⁰C, 1200 rpm, and for 14 hours. Concentrations were varied at 0, 5, 20, 50, and 100 ppm. The test was carried out for low carbon steel JIS G3123 grade SGD 400D in a corrosion medium in the form of 1.5% NaCl solution which had been flowed with CO2 gas. The highest efficiencies were obtained at the concentration of 100 ppm and the values were 62.12 and 93.52% for TETA-PCO A and B respectively. SEM-EDX results support the high efficiency of  TETA-PCO B. The type of corrosion that occured was pitting corrosion. The adsorption of  TETA-PCO B on the steel surface is a strong physisorption and is in accordance with the Langmuir isotherm model."

"Kemampuan inhibisi korosi senyawa fenolik minyak zaitun pada baja API 5L Grade B di lingkungan NaCl 3,5 % diinvestigasi dengan menggunakan pengujian Tafel polarisasi dan Electrochemical Impedance Spectroscopy (EIS). Senyawa fenolik minyak zaitun yang berperan dalam menginhibisi korosi diinvestigasi dengan pengujian FTIR. Senyawa oleuropein dalam minyak zaitun berperan dalam menginhibisi korosi pada sistem dengan tipe mixed inhibitor. Efisiensi inhibisi optimal terjadi pada konsentrasi 1 ml minyak zaitun/100 ml NaCl. Efisiensi inhibisi akan menurun seiring dengan kenaikan temperatur. Senyawa oleuropein menginhibisi korosi dengan cara adsorpsi fisika (interaksi elektrostatis) pada permukaan logam membentuk lapisan tunggal yang akan menghambat transfer muatan dan massa. Adsorpsi senyawa fenolik minyak zaitun pada permukaan logam terjadi spontan mengikuti Langmuir adsorpsi isoterm. Adsorpsi senyawa fenolik minyak zaitun akan meningkatkan energi aktivasi proses korosi. Hasil pengujian menunjukkan bahwa senyawa fenolik minyak zaitun dapat digunakan sebagai alternatif inhibitor ramah lingkungan pada baja API 5L Grade B di lingkungan NaCl 3,5 %.

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Corrosion inhibition ability of olive oil phenolic compounds on API 5L Grade B steel in 3.5% NaCl environment was investigated using Tafel polarization and Electrochemical Impedance Spectroscopy (EIS) test. Olive oil phenolic compounds that acts for inhibit corrosion process was investigated by FTIR test. Oleuropein compounds in olive oil acts for inhibit corrosion process in the system with mixed type inhibitors. Optimal inhibition efficiency occurs at a concentration 1 ml olive oil/100 ml NaCl. Inhibition efficiency decreases with increasing temperature. Oleuropein compounds inhibit corrosion by physisorption (electrostatic interactions) on the metal surface to form a single layer that will inhibit the charge and mass transfer. Adsorption of olive oil phenolic compounds on the metal surface occurs spontaneously follow the Langmuir adsorption isotherm. Adsorption of olive oil phenolic compounds will increase the activation energy of the corrosion process. The results showed that olive oil phenolic compounds can be used as an alternative green corrosion inhibitor on API 5L Grade B steel in 3.5% NaCl environment."

"Indonesia memiliki potensi cengkeh yang melimpah,daunnya dapat gugur setiap minggunya 0.96 kg/pohon. Inhibitor yang digunakan adalah ekstrak daun cengkeh dengan konsentrasi 1ml,2ml,3ml,4ml,5ml dan minyak cengkeh dengan konsentrasi 2ml,4ml,6ml,8ml,10ml. Pengujian dilakukan dengan metode linear polarisasi, Fourier Transform Infrared Spectroscopy ( FTIR ), Gas Chromatography Mass Spectroscopy ( GCMS ), dan Eletrochemical Impedance Spectroscopy ( EIS ). Konsentrasi optimum pada ekstrak daun cengkeh berada pada konsentrasi 4 ml dengan laju korosi 0.042 mm/year dan efisiensi 46.6 % sedangkan minyak cengkeh konsentrasi optimumnya berada pada konsentrasi 8 ml dengan laju korosi 0.001 mm/year dengan efisiensi 98.6 %. FTIR menunjukkan gugus - gugus fungsi yang berada di dalam inhibitor dan diperkuat dengan hasil GCMS untuk mengetahui senyawa aktif yang berada dalam inhibitor. Pengujian FTIR juga menunjukkan bahwa gugus - gugus fungsi pada inhibitor menempel pada permukaan sampel ketika sampel di rendam. Mekanisme adsorpsi dari kedua inhibitor adalah physical adsorption dengan nilai ΔGads pada inhibitor ekstrak daun cengkeh sebesar -7.575 kJ/mol, dan - 12.142 kJ/mol untuk inhibitor minyak cengkeh. EIS menunjukkan adanya peningkatan nilai tahanan charge transfer pada setiap kenaikan konsentrasi inhibitor dan nilai dari Cdl menurun yang menunjukkan bahwa terjadi pembentukan lapisan protektif. Nilai charge transfer dari inhibitor minyak cengkeh lebih besar yang berarti minyak cengkeh memiliki kemampuan inhibisi lebih baik dan ini diperkuat dari hasil polarisasi. Kedua jenis inhibitor ini termasuk dalam jenis inhibitor campuran (mix type inhibitor).

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Indonesia has abundant potential clove, leaves can fall every week 0.96 kg/tree. Inhibitor which used on this research are clove leave extract with concentration 1ml,2ml,3ml,4ml,5ml and clove oil with concentration 2ml,4ml,6ml,8ml,10ml. Inhibitor are examined by linear polarization, Fourier Transform Infrared Spectroscopy ( FTIR ), Gas Chromatography Mass Spectroscopy ( GCMS ), and Electrochemical Impedance Spectroscopy ( EIS ). The result show that optimum concentration of clove leave extract is at 4 ml with corrosion rate 0.042 mm/year and efficiency 46.6% where as optimum concentration of clove oil is at 8 ml with corrosion rate 0.001 mm/year and efficiency 98.6 %. FTIR obtain functional group which contained in inhibitor and GCMS result also show active compound in inhibitor. FTIR show that functional group in inhibitor adsorp on the metal surface when sample is soaked in inhibitor. Adsorption mechanism of these inhibitor is physical adsorption with ΔGads of clove leave extract inhibitor is -7.575 kJ/mol, and - 12.142 kJ/mol for clove oil inhibitor. EIS show increasing charge transfer resistance with increasing inhibitor concentration and decreasing Cdl also show there are protective film forming. The charge transfer resistance of clove oil inhibitor higher, means clove oil has better inhibition than clove leaves extract. Both of these inhibitor are included in mix type inhibitor."

"Material baja karbon API 5L Grade B banyak digunakan dalam industri minyak dan gas dengan sistem operasi tekanan dan suhu yang cukup tinggi. Penelitian ini dilakukan terhadap analisis korosi pipa penyalur bahan bakar di wilayah Jakarta terhadap manajemen resiko berdasarkan nilai index sum dan menganalisis perilaku korosi sampel material pipa API 5L Grade B berupa struktur mikro, pengaruh sifat mekanis, dan laju korosi pada pipa penyalur. Hasil analisa memperlihatkan bahwa pipa API 5L Grade B yang digunakan sebagai jalur distribusi bahan bakar ditemukan adanya cacat yang pada awalnya berupa korosi seragam kemudian membentuk korosi celah setelah itu membentuk korosi sumuran dan berakibat pada kemunduran bahan pipa dengan tingkat resiko pipa penyalur berada pada level medium risk.

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Carbon steel material API 5L Grade B was used by industry of the oil and gas with the pressure operating system and with high enough temperature. This research was conducted to corrosion analysis pipelines for fuel in Jakarta on risk management based on the value of the index sum and analyze the corrosion behavior of the material sample pipe API 5L Grade B is a micro-structure, the influence of mechanical properties and corrosion rate in the conduit.

The results of the analysis showed that the pipe API 5L Grade B used as a distribution line of fuel is defects and the result is deterioration of pipe materials with the risk level of the pipeline is at the medium level of risk."

"[ABSTRAKKorosi pada tubing baja karbon merupakan masalah serius bagi eksplorasi dan produksi minyak dan gas. Perilaku korosi baja paduan rendah 3%Cr (3Cr) dan baja karbon J55 dalam lingkungan air formasi diinvesitigasi dengan menggunakan pengujian tafel polarisasi potensiodinamik, electrochemical impedance spectroscopy (EIS) dan pengamatan metalografi. Komposisi dan morfologi dari produk korosi kedua baja dianalisa dengan energy dispersive spectroscopy (EDS) dan scanning electron microscopy (SEM). Hasil pengujian memperlihatkan adanya korosi lokal pada baja J55 dengan struktur mikro pro-eutektoit ferit dan perlit, dan tidak terlihat pada baja 3Cr dengan struktur mikro martensit temper dikarenakan terbentuknya lapisan produk korosi kaya-Cr yang padat, kontinyu dan melekat dengan baik ke permukaan baja. Lapisan produk korosi yang bercelah dan tidak kontinyu pada baja J55 menyediakan jalan bagi ion-ion agresif untuk masuk dan menimbulkan korosi lokal pada permukaan baja.ABSTRACTCorrosion of carbon steel tubings is a serious problem for oil and gas wet exploration and production. Corrosion behaviour of low bearing 3%Cr (3Cr) alloy steel and J55 carbon steel in produced water were investigated by polarisation potentiodynamic tafel, electrochemical impedance spectroscopy (EIS) and metallography observation. The composition and morphology of corrosion products were analyzed by energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The results show that there was localized corrosion was observed in J55 carbon steel with pro-eutectoid ferrite and pearlite microstructure, which did not exist in 3Cr steel with tempered martensite microstructure due to formation of a dense, continuous and adherent Cr-rich scale on surface steel. Many pits in the less adherent corrosion scale of J55 carbon steel could build up ion-diffusion channels which would degrade the protective capabilities of the product films and aggravate localized corrosion.;Corrosion of carbon steel tubings is a serious problem for oil and gas wet exploration and production. Corrosion behaviour of low bearing 3%Cr (3Cr) alloy steel and J55 carbon steel in produced water were investigated by polarisation potentiodynamic tafel, electrochemical impedance spectroscopy (EIS) and metallography observation. The composition and morphology of corrosion products were analyzed by energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The results show that there was localized corrosion was observed in J55 carbon steel with pro-eutectoid ferrite and pearlite microstructure, which did not exist in 3Cr steel with tempered martensite microstructure due to formation of a dense, continuous and adherent Cr-rich scale on surface steel. Many pits in the less adherent corrosion scale of J55 carbon steel could build up ion-diffusion channels which would degrade the protective capabilities of the product films and aggravate localized corrosion.;Corrosion of carbon steel tubings is a serious problem for oil and gas wet exploration and production. Corrosion behaviour of low bearing 3%Cr (3Cr) alloy steel and J55 carbon steel in produced water were investigated by polarisation potentiodynamic tafel, electrochemical impedance spectroscopy (EIS) and metallography observation. The composition and morphology of corrosion products were analyzed by energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The results show that there was localized corrosion was observed in J55 carbon steel with pro-eutectoid ferrite and pearlite microstructure, which did not exist in 3Cr steel with tempered martensite microstructure due to formation of a dense, continuous and adherent Cr-rich scale on surface steel. Many pits in the less adherent corrosion scale of J55 carbon steel could build up ion-diffusion channels which would degrade the protective capabilities of the product films and aggravate localized corrosion., Corrosion of carbon steel tubings is a serious problem for oil and gas wet exploration and production. Corrosion behaviour of low bearing 3%Cr (3Cr) alloy steel and J55 carbon steel in produced water were investigated by polarisation potentiodynamic tafel, electrochemical impedance spectroscopy (EIS) and metallography observation. The composition and morphology of corrosion products were analyzed by energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The results show that there was localized corrosion was observed in J55 carbon steel with pro-eutectoid ferrite and pearlite microstructure, which did not exist in 3Cr steel with tempered martensite microstructure due to formation of a dense, continuous and adherent Cr-rich scale on surface steel. Many pits in the less adherent corrosion scale of J55 carbon steel could build up ion-diffusion channels which would degrade the protective capabilities of the product films and aggravate localized corrosion.]"

"Kemampuan kombinasi ekstrak temulawak Curcuma Xanthorrhiza dan bawang Dayak Eleutherine Americana sebagai inhibitor ramah lingkungan untuk baja karbon API 5L X42 pada lingkungan HCl 1M diinvestigasi dengan pengujian tafel, weight loss, polarisasi, Electrochemical Impedance Spectroscopy EIS , dan Fourier Transform Infrared Spectroscopy FTIR . Senyawa flavonoid dan antioksidan yang berperan untuk menginhibisi korosi diinvestigasi melalui pengujian FTIR. Selain itu, lapisan yang terbentuk di permukaan logam juga dipelajari dengan menggunakan metode adsorpsi Langmuir isotherm. Campuran ekstrak temulawak dan bawang Dayak merupakan inhibitor jenis campuran, dan dominan pada katodik. Efisiensi inhibisi paling tinggi didapatkan dengan persentase 80 :20 yaitu 91,78 . Campuran ekstrak temulawak dan bawang Dayak dapat digunakan sebagai alternatif inhibitor ramah lingkungan untuk baja karbon API 5L X42 pada lingkungan asam.

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This study aimed to investigate the ability of combination from Curcuma Xanthorrhiza and Eleutherine Americana extract as an environment friendly inhibitor for API 5L X42 steel in 1M HCl environment. Corrosion inhibition ability of this extract was tested using weight loss, tafel polarization, electrochemical impedance spectroscopy methods, and fourier transform infrared spectroscopy. FTIR test was used to investigate flavonoid and antioxidant compound that plays an important role to inhibit corrosion. In addition, formed layer on the metal surface was also studied using Langmuir isotherm adsorption methode. It can be concluded that combination from Curcuma Xanthorrhiza and Eleutherine Americana extract could be used as an alternative and environmental friendly inhibitor for API 5L X42 steel in acidid environment."

"Efek penghambatan dari ekstrak Curcuma xanthorhizza pada korosi baja API 5L Grade X42 dalam larutan HCl 1M diselidiki dengan menggunakan metode kehilangan berat, polarisasi tafel, dan metode electrochemical impedance spectroscopy EIS . Uji FTIR digunakan untuk menyelidiki senyawa antioksidan yang berperan penting dalam menghambat korosi. Dalam penelitian ini konsentrasi ekstrak temulawak yang digunakan adalah 0 ppm, 100 ppm, 250 ppm, 500 ppm, dan 1000 ppm.Hasilnya menunjukkan bahwa temulawak dapat menghambat korosi pada baja dan bertindak sebagai penghambat tipe campuran. Laju korosi menurun seiring dengan meningkatnya konsentrasi inhibitor. Sedangkan efisiensi inhibisi meningkat dengan meningkatnya konsentrasi inhibitor. Adsorpsi ekstrak pada permukaan baja mengikuti Langmuir isotherm. Nilai energi bebas ?Gads menunjukkan bahwa adsorpsi molekul inhibitor secara fisika. Dapat disimpulkan bahwa ekstrak Curcuma xanthorhizza dapat digunakan sebagai penghambat alternatif dan ramah lingkungan untuk baja API 5L Grade X42 di lingkungan asam.

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The inhibitory effect of the extract of Curcuma xanthorhizza on the corrosion of API 5L Grade X42 steelin HCl 1M solution was investigated by using weight loss, tafel polarization, and electrochemical impedance spectroscopy methods.FTIR test was used to investigate the antioxidant compound that plays an important role to inhibit corrosion.In this study the concentration of Curcuma xanthorhizza extract used was 0 ppm, 100 ppm, 250 ppm, 500 ppm, and 1000 ppm.

The results show that Curcuma xanthorhizza inhibit the steel corrosion and act as mixed type inhibitors. The corrosion rate decreases with the increasing of inhibitors concentrations. At the same time, inhibition efficiency increases with the increase of inhibitors concentrations.The adsorption of extract on the steel surface was found to obey Langmuir rsquo s adsorption isotherm. The free energy value Gads indicated that the adsorption of inhibitor molecules was typical of physisorption.It can be concluded that Curcuma xanthorhizza extract could be used as an alternative and environmental friendly inhibitor for API 5LGrade X42 steel in acidic environment."

"80% kegagalan material baja pada fasilitas produksi industri minyak dan gas bumi disebabkan oleh proses korosi. Salah satu pengendalian proses korosi material baja API 5L Grade X60 dengan menggunakan inhibitor ramah lingkungan. Pada penelitian ini, ekstrak kayu secang (Caesalpinia Sappan L.) dievaluasi sebagai inhibitor ramah lingkungan untuk baja API 5L X60 di lingkugan HCl 1M dengan variasi volume ekstrak 0,5 ml, 1 ml, 1,5 ml, 2 ml, 3ml dan variasi temperatur 302K, 312K, 322K, dan 332K menggunakan metode polarisasi tafel, Electrochemical Impedance Spectroscopy (EIS), Fourier Transform Infra-red Spectroscopy (FTIR), dan Stimultaneous Thermal Analysis (STA). Hasil dari pengujian polarisasi tafel dan EIS menunjukan ekstrak kayu secang bertindak sebagai inhibitor campuran (Mixed Inhibitor). Efisiensi optimal dihasilkan dari penambahan volume ekstrak sebesar 1,5 ml dalam 400 ml HCl 1M. sebesar 91 % polarisasi tafel, dan sebesar 94% EIS. Rapat arus korosi material pada volume 1,5 ml ekstrak kayu secang sebesar 57 µA/cm2 dan nilai resistivitas larutan 841 ?.cm2. Kenaikan temperatur lingkungan sebesar 332 K menaikan rapat arus korosi material menjadi 139 µA/cm2 dan menurunkan nilai resistivitas larutan sampai 121 ?.cm2, sehingga nilai efisiensi inhibitor turun sampai 50%. Gugus fungsi keton (C=O) muncul dari hasil karakterisasi pengujian FTIR yang menandakan keberadaan senyawa brazilein dan dan sappanchalcone.

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80 % failure of carbon steel at oil and gas production facility was caused by corrosion. One of corrosion mitigation of carbon steel was used green inhibitor. In this study, Caesalpinia Sappan L. extract has been evaluated as green inhibitor corrosion for API 5L X60 in HCl 1M environment with variation of volume extract 0,5 ml, 1ml, 1,5 ml, 2ml, 3ml and variation of temperature 302K, 312K, 322K, and 332K using Tafel polarization and Electrochemical Impedance Spectroscopy (EIS), Fourier Transform Infra-red Spectroscopy (FTIR), dan Stimultaneous Thermal Analysis (STA).The Result show the tafel polarization and EIS show caesalpinia sappan extract acts for inhibit corrosion process in the system with mixed type inhibitor. Optimal inhibiton efficiency occurs at volume 1.5 ml extract caesalpinnia sappan/400 ml HCl 1M, 91% for tafel polarization and 94% for EIS. Current density at volume extract 1,5 ml was 57 µA/cm2 and resistivity of solution 841 ?.cm2. Increasing temperatur of environment will increase current density to 139 µA/cm2 and decrease resistivity to 121 ?.cm2. So, the inhibition efficiency decrease to 50%. Keton fuctional group was found showed exisstance of showed that brazilein dan dan sappanchalcone"