Gadang Priyotomo

Corrosion Behavior of Ni3(Si,Ti) + 2Mo in Hydrochloric Acid Solution

The corrosion behaviour of the intermetallic compounds Ni3(Si,Ti) (L12: single phase), has been investigated using an immersion test, electrochemical method, scanning electron microscope in 0.5 kmol/m3 HCl at 303 K. In addition, the corrosion behaviour of austenitic stainless steel type 304 and C276 was studied under the same experimental conditions as references. It was found that the intergranular attack was observed for Ni3(Si,Ti) in the immersion test. From the immersion test and polarization curves, Ni3(Si,Ti) had the moderate corrosion resistance, while the corrosion resistances of C 276 and type 304 were the highest and the lowest. Ni3(Si,Ti) and type 304 were difficult to form a stable passive film, but not for C276. A further experiment must be conducted to clarify the stability of film for Ni3(Si,Ti) in detail.

The Corrosion Behavior of Ni3Al/Ni3V Two-Phase Intermetallic Compounds in Various Acidic Solutions

The corrosion behavior of the Ni3Al/Ni3V two-phase intermetallic compounds with and without minor elements (Nb, Co, and Cr) to be composed of L12 phase (Ni3Al) and a mixed phase of L12 (Ni3Al) and D022 (Ni3V) has been investigated by using an immersion test in 0.5u2009kmol/m3 HCl, H2SO4, and HNO3 solutions. The surface morphology was observed before and after the immersion test by scanning electron microscope (SEM). The results were compared to those of the L12 single-phase Ni3(Si,Ti) and austenitic stainless steel type 304. In all acidic solutions, preferential dissolution of (L12

Atmospheric corrosion performance of different steels in early exposure in the coastal area region West Java, Indonesia

The performance of carbon steel, galvanized steel and aluminium after one month exposed in the atmospheric coastal area, which is in Limbangan and Karangsong Beach, West Java, Indonesia was evaluat...

Studi Deteksi Dini Korosi Pada Logam Baja Dengan Menggunakan Material Cerdik Berbahan Akrilik

Di bidang manufaktur dan industri, dregradasi perfoma logam baja akibat proses korosi merupakan gabungan reaksi oksidasi di anoda dan reaksi reduksi di katoda sehingga tercipta sel elektrokimia. Proses korosi terjadi pada logam yang terlapisi lapisan polimer akibat preparasi permukaan logam subtrak yang tidak benar. Dalam aplikasi luar, dibutuhkan material senyawa cerdik sebagai indikator terjadinya proses korosi sebelum terjadi kerusakan berlanjut pada logam baja. Material senyawa cerdik dengan variasi konsentrasi 0.01 persen 0,1 persen dan 1 persen phenolphthalein dan coumarin di dalam sistem lapisan akrilik. Pengujian menggunakan Uji Kabut Garam berstandar ASTM B117-97 dengan waktu ekspos 144 jam. Observasi kerusakan menggunakan visual makro. Hasil uji kabut garam tersebut menunjukkan kinerja phenolpthalein konsentrasi 0.01 persen dan 1 persenmenunjukan spot warna jingga di 24 jam sedangkan coumarin menunjukkan warna pendaran hijau di konsentrasi 1 persen. Daerah antar muka polimer akrilik dan substrak baja diindikasikan sebagai daerah terjadinya reaksi elektrokimia yang ditandai dengan indikasi warna dan floresensi. National Seminar 2014. Hlm 1-6

Identification of biofilm-forming bacteria from steel panels exposed in sea waters of Jakarta Bay and Madura Strait

Biofouling formation on marine constructions may cause significant problem such as bridge and vessel damages. Bacterial biofilms are the initiating cause of biofouling. Unfortunately, information of identified biofilm-forming bacteria associated with biofouling process in Indonesian seawaters was still limited. The purpose of this study was to identify biofilm-forming bacteria from biofouling of surface of steel panels exposed in Seawaters of Jakarta Bay and Madura Strait. Steel panels coated either with antifouling or anticorrosion paints were put into sea waters of Jakarta Bay and Madura Strait. Isolation of bacteria was conducted from steel panels fully covered by fouling organisms and on surface without fouling. Confirmation of biofilm-forming activities was performed based on crystal violets-stained bacterial materials on polystyrene well plates. As results, accumulation of macroorganisms and microorganisms was recognized visually on anticorrosion-coated panel that had been put in all observed sea waters for one month. However, biofouling appearances were not recognized on the antifouling-coated panel. Bacterial colonies isolated from Jakarta Bay (108 isolates) and Madura Strait (30 isolates) were screened for biofilm formation on polystyrene well plates. Five isolates representing the most active strain to biofouling activity were then identified based on 16S rRNA gene sequences. As results, isolates of Jakarta Bay C021.MB.1.8, C221.MB.II.11, and C221.MB.II.12 was closely related to Vibrio alginolyticus (99 % similarity). Another two isolates of Madura Strait J111.SM and J111.1.10-6.S had similarity to Vibrio natriegens (99 % to 100 %). All these biofilm-forming bacteria were isolated from biofouling of panels coated with anticorrosion paints. In addition, we confirmed that V. alginolyticus C021.MB.1.8 formed biofilm only if growth medium is seawater from Jakarta Bay. Our study and the bacterial collections will be useful for evaluating and developing new antifouling paints that will be applied in sea waters of these two sites.Biofouling formation on marine constructions may cause significant problem such as bridge and vessel damages. Bacterial biofilms are the initiating cause of biofouling. Unfortunately, information of identified biofilm-forming bacteria associated with biofouling process in Indonesian seawaters was still limited. The purpose of this study was to identify biofilm-forming bacteria from biofouling of surface of steel panels exposed in Seawaters of Jakarta Bay and Madura Strait. Steel panels coated either with antifouling or anticorrosion paints were put into sea waters of Jakarta Bay and Madura Strait. Isolation of bacteria was conducted from steel panels fully covered by fouling organisms and on surface without fouling. Confirmation of biofilm-forming activities was performed based on crystal violets-stained bacterial materials on polystyrene well plates. As results, accumulation of macroorganisms and microorganisms was recognized visually on anticorrosion-coated panel that had been put in all observed sea wa...

Corrosion performance of steel and galvanized steel in Karangsong and Limbangan sea water environment

Due to wide spread use of steel and galvanized steelin Indonesia, it is important to study corrosion behavior of these materials in marine environments. Thus, corrosion performance of those materials was conducted in Karangsong and Limbangan. Since, the surface data was not available in the literature. Those materials were immersed in sea water for 27 days. The corrosion measurement was conducted by weight loss. Sea water parameter such as temperature, pH, salinity, DO (Dissolved Oxygen), and conductivity were measured. SEM-EDS was conducted to see corrosion morphology. The results showed that mild steel was more corroded than galvanized steel in both seawater environments. Corrosion rate of mild steel and galvanized steel in the Karangsong sea water were 29.5 and 8.4 mpy respectively, and corrosion rate of mild steel and galvanized steel in Limbangan sea water were 25.5 and 7.6 mpy respectively.Due to wide spread use of steel and galvanized steelin Indonesia, it is important to study corrosion behavior of these materials in marine environments. Thus, corrosion performance of those materials was conducted in Karangsong and Limbangan. Since, the surface data was not available in the literature. Those materials were immersed in sea water for 27 days. The corrosion measurement was conducted by weight loss. Sea water parameter such as temperature, pH, salinity, DO (Dissolved Oxygen), and conductivity were measured. SEM-EDS was conducted to see corrosion morphology. The results showed that mild steel was more corroded than galvanized steel in both seawater environments. Corrosion rate of mild steel and galvanized steel in the Karangsong sea water were 29.5 and 8.4 mpy respectively, and corrosion rate of mild steel and galvanized steel in Limbangan sea water were 25.5 and 7.6 mpy respectively.

The Selection of Magnesium alloys as Sacrificial Anode for the Cathodic Protection of Underground Steel Structure

Various characterization 4 type of Mgsacrificial anodes (A,B,C and D from differentproducts) have been conducted such as chemicalcomposition, closed and opened potential, currentcapacity and efficiency test by galvanostatic method.On the basis of the results, the presence of impuritieselement gives detrimental effects of electrochemicalproperties and anode efficiency. The presence ofhigh concentration of impurities for Cu, Fe and Nihave cathodic effect to Mg anode such as anode Aand B , where the indication of galvanic corrosiontake place in Mg anode. Mg anode A and B werelower current capacities, current efficiencies andconsumption rates than Mg anode C and D. Mganode A and B have a lower performance comparedto Mg anode C and D Mg anode A and B are noteligible become a standard sacrificial anodes toprotect steel structure in soil. International Journal of Engineering Trends and Technology (IJETT) – Volume 51 Number 2 September 2017

Evaluation of anticorrosion and antifouling paint performance after exposure under seawater Surabaya–Madura (Suramadu) bridge

Antifouling paints are used widely to coat the underwater structures to prevent various fouling organisms. The evaluation of the performance for the two commercial anticorrosion and antifouling paints was carried out in the piles of Suramadu Bridge, East Java during 1 month exposure. The 20u2005cm width × 25u2005cm high × 0.3u2005cm thick specimens of mild steel were sandblasted and coated by anticorrosion and antifouling paint. Blank specimen (without exposed) were also prepared as a control. On the other hand, the 7.5u2005cm width × 15u2005cm high × 0.3u2005cm thick specimen bare mild steel was prepared for measure the corrosion rate throught weight loss method. The test panels containing specimens were exposure up to 1 month for immersion in splash zone and tidal zone (0, 1, 3, meters from sea level). Sea water parameters consisting of temperature, pH, salinity, conductivity and dissolved oxygen (DO) were also measured. The thickness, glossy, hardness and adhesion strength of the coating performance were carried out. The resu...

The effect of pH on the corrosion behavior of intermetallic compounds Ni3(Si,Ti) and Ni3(Si,Ti) + 2Mo in sodium chloride solutions

The corrosion behavior of the intermetallic compounds, Ni3(Si,Ti) (L12: single phase) and Ni3(Si,Ti) + 2Mo (L12 and (L12 + Niss) mixture region), has been investigated using an immersion test, electrochemical method and surface analytical method (SEM; scanning electron microscope and EDAX: Energy Dispersive X-ray) in 0.5 kmol/m3 NaCl solutions at various pH. The corrosion behavior of nickel alloy C-276 was studied under the same experimental conditions as a reference. It was found that the uniform attack was observed on Ni3(Si,Ti) for the immersion test at lower pH, while the pitting attack was observed on this compound for this test at neutral solution. Furthermore, Ni3(Si,Ti)+2Mo had the preferential dissolution of L12 compared to (L12 + Niss) mixture region at lower pH, while pitting attack occurred in (L12 + Niss) mixture region at neutral solution. For both intermetallic compounds, the magnitude of pitting and uniform attack decrease with increasing pH of solutions. From the immersion test and polari...

The influences of applied stress, test temperature, and concentration on environment-induced cracking of Ni3 (Si,Ti) intermetallic compound in neutral sodium chloride solutions

The environment-induced cracking (EIC) behavior of Ni3 (Si,Ti) intermetallic compound was investigated as functions of applied stress, test temperature and chloride-ion concentration in NaCl solution by 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 EIC-dominated region was constant independent 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 in terms of hydrogen entry, dissolution and film formation. Article in press, 2014