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"Reinforced concrete structure are subjected to damage and deterioration during their service life because of exposure to many types of environmental influence. These damages or deterioration can reduce the performance and intended function of the structure. On several occasions structural failures are closely linked to the corrosion of steel reinforcement in concrete."

"Summary:A companion to the title Corrosion Chemistry, this volume covers both the theoretical aspects of cathodic protection and the practical applications of the technology, including the most cutting-edge processes and theories"

"Paduan aluminium 2024 dan 7075 adalah material yang digunakan pada penelitian ini untuk mengetahui mekanisme korosi retak tegang (SCC) yang diakibatkan oleh proses penuaan (age hardening). Persiapan sampel dilakukan sesuai dengan ASTM G 49, sedangkan pengujian SCC dengan teknik pembebanan tarik secara langsung. Larutan pengujian terdiri dari 3% NaCl + 0,5% H2O2, pH 3, waktu pencelupan selama 48 jam. Karakteristik dari perpatahan yang dipengaruhi oleh SCC dianalisa dengan menggunakan scanning electron microscope (SEM) dan optical microscope (OM). Hasil dari penelitian ini menunjukkan bahwa paduan aluminium 2024 dengan perlakuan natural aging lebih mudah terserang SCC dibandingkan dengan perlakuan over aging, namun demikian over aging mengakibatkan ketahanan terhadap korosi exfoliasi menurun. Paduan aluminium 7075 dengan perlakuan over aging memperlihatkan ketahanan SCC yang lebih baik dibandingkan dengan perlakuan artificial aging. Hal tersebut dibuktikan dengan keberadaan presipitat yang dihasilkan pada struktur mikro dari hasil proses penuaan.

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Two types of aluminum alloys, 2024 and 7075 have been selected in this study to investigate mechanism of stress corrosion cracking due to many forms of age hardening process. Stress corrosion cracking test using the direct tension stress corrosion technique were carried out on these aluminum alloys and the specimens were prepared as mentioned in G 49 ASTM. This test was carried out by immersing the specimens in 3% natrium chloride (NaCl) + 0.5% peroxide (H 2O2), used pH of 3 for 48h. The characteristic of fracture which is affected by stress corrosion cracking test was analyzed by means of scanning electron microscope (SEM) and optical microscope (OM).

The results showed that the susceptibility to stress corrosion cracking for aluminum alloy 2024 with natural aging is higher than the type with over aging condition although in this condition it has the worst exfoliation corrosion resistance. Meanwhile, aluminum alloy 7075, at over aging condition gives better stress corrosion cracking resistance rather than the artificial aging condition. These results refer to the precipitate in microstructure which is formed as a result of aging process."

"Tesis ini mempelajari mengenai pengaruh injeksi ekstrak daun kenikir sebagai green corrosion inhibitor pada baja karbon dalam larutan 0.5M H2SO4. Dengan pengujian weight loss diperlihatkan bahwa inhibitor ekstrak daun kenikir mampu menurunkan laju korosi dengan efisiensi 71.66 % pada konsentrasi inhibitor sebesar 4000 ppm. Dari pengujian polarisasi ditunjukkan bahwa inhibitor ekstrak daun kenikir menggeser kurva polarisasi kearah atodik dan katodik (mixed type inhibitor), yang menunjukkan ciri utama sebagai inhibitor dari bahan organik. Pengujian dengan FTIR dan EDX memperkuat dugaan bahwa inhibitor ekstrak daun kenikir sebagai inhibitor adsorpsi / film forming.

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This thesis is intended to study the influences of cosmos leaf extract injection as corrosion inhibitor for carbon steel in 0.5M H2SO4. By weight loss analysis, it show that inhibitor from cosmos leaf extract can reduce corrosion rate with efficiency up to 71.66 % under inhibitor injection about 4000 ppm.

With polarization, it is shown that inhibitor shift polarisation curves for both of anodic and cathodic polarisation (mixed type inhibitor), shows that inhibitor have characteristic as inhibitor from organic material. FTIR and EDX analysis can be concluded that inhibitor from cosmos leaf extract act inhibition by adsorption/film forming corrosion inhibitor."

"Permasalahan korosi dalam bidang minyak dan gas, menjadi salah satu perhatian serius. Proses penanganan korosi ini dilakukan dengan dua klasifikasi metode yaitu secara fisika dan kimia. Pada penelitian ini dilakukan penanganan korosi secara kimia menggunakan 2-mercaptobenzothiazole (MBT) sebagai inhibitor korosi pada tembaga. Pengamatan dilakukan menggunakan metode berat hilang dan polarisasi ekstrapolasi Tafel dalam larutan yang mengandung ion klorida (HCl dan brine). Karakteristik film yang terbentuk diamati menggunakan spektrofotometer ATR-IR dan spektrofotometer UV Vis. Studi morfologi hasil menggunakan SEM. Hasil penelitian menunjukkan bahwa terbentuknya film Cu(II)-2-mercaptobenzothiazole pada permukaan tembaga melalui mekanisme adsorpsi isotermal Langmuir. Peningkatan konsentrasi MBT akan meningkatkan % inhibisi pada tembaga dari proses korosi, sedangkan peningkatan temperatur akan menurunkan % inhibisi korosi pada tembaga dikonsentrasi yang sama. Aplikasi penggunaan MBT dengan konsentrasi minimal 25 ppm pada temperatur 70 oC dengan waktu kontak 72 jam memberikan % inhibisi diatas 90,00 % pada brine sintetis.

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Corrosion problems in oil and gas fields are very serious concern. Corrosion treatment process is used by two methods, physical and chemical. In this research, the corrosion treatment by chemical method with 2-mercaptobenzothiazole (MBT) as a corrosion inhibitor in copper. This research used weight loss method and polarization with extrapolation Tafel in solution which chloride ion contains (HCl and brine). Characteristic of film layer using ATR-IR spectrophotometer and UV Vis spectrophotometer. Surface morphological study was observed on SEM.

The results showed that formed Cu(II)-2-mercaptobenzothiazole on copper surface through the Langmuir isothermal adsorption mechanism. Increasing of concentration MBT will improve the % inhibition of copper from the corrosion process, whereas an increase in temperature will decrease the % corrosion inhibition of copper in the same concentration. The application of MBT in the minimal concentration 25 ppm at 70 °C in 72 hours contact times gave % inhibition value more than 90.00 % in synthetic brine."

"ABSTRAKPenelitian ini difokuskan pada analisa korosi pipa trunk line yangmenyebabkan pipa diganti dalam waktu 8 tahun dari 15 tahun rencana desain.Material baja API 5L Grade B dalam kondisi belum terpakai dan yang terkorosidianalisis secara fisik dan mekanik menggunakan uji metalografi, uji tarik, ujikomposisi kimia, Scanning electron microscopy-Energy Dispersive Spectroscopy(SEM-EDS), Difraksi Sinar-X (XRD), kemudian uji korosi dengan metodepolarisasi. Pada sampel belum terpakai diperoleh nilai laju korosi 0,0531 mmpydan sampel terkorosi diperoleh nilai 0,1377 mmpy. Juga terbentuk fasa Fe3O4(magnetite), FeS (besi sulfida) dan SiO2 (silika). Hasil data di lapangan berupakondisi sekitar jalur pipa trunk line dan laju korosi yang dihasilkan akibatpenurunan ketebalan menghasilkan data sisa umur pakai aktual yang dibandingkandengan sisa umur pakai sampel hasil pengujian.

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ABSTRACTThis research focused on the trunk line corrosion analysis that has causedpipe replacement within 8 years instead of 15 years design lifetime. Samples ofAPI 5L Grade B material were analyzed with physical and mechanical tests usingmetallographic, tensile testing, chemical composition test, scanning electronmicroscopy-energy dispersive spectroscopy (SEM-EDS), X-Ray difraction (XRD),then polarization corrosion test. On the new unused sample obtained corrosion Adeof 0.0531 mmpy and corroded sample obtained 0.1377 mmpy. Also formed phaseFe3O4 ( magnetite ) , FeS ( iron sulfide ) and SiO2 ( silica ). The results of fielddata in the form of conditions around the trunk line area and the pipeline corrosionrate generated due to decreased thickness obtained the actual remaining life datacompared with the remaining lifetime of the sample test"