Effect of Sulfuric Acid Patination Treatment on Atmospheric Corrosion of Weathering Steel

The requirements for the formation of a protective patina on conventional weathering steels (WS) are well known in the scientific literature related to civil structures. However, these criteria are not always given due consideration when WS is used in cultural heritage, as in the case of sculptural work. An artificial patina was produced simulating artists’ working procedures using a direct patination technique, applying a solution of 10% H2SO4 on WS specimens. These were exposed for two years in the urban atmosphere of Madrid along with weathering steel specimens without artificial patina, called natural patina. The patinas generated have been analyzed using colorimetry, micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thickness measurements.The artificial patina color formed hardly differs from the color that the natural patina acquires from practically the beginning of its formation in the atmosphere of Madrid. After two years, the atmospheric corrosion rate of patinated WS is lower than 6 µm/year. The sulfuric acid treatment accelerates the protective ability of the patina with respect to the natural patina according to the ratio goethite to lepidocrocite (α/γ). Chromium-rich goethite is located in the inner part of the artificial patina as well as chromium-rich ferrihydrite. Ferrihydrite may act as a precursor of nanophasic goethite.

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Pengaruh Suhu dan Konsentrasi terhadap Proses Pemisahan Nikel dari Logam Pengotor Menggunakan Metode Leaching

FLUIDA ◽

10.35313/fluida.v13i2.2388 ◽

2020 ◽

Vol 13 (2) ◽

pp. 81-92

Author(s):

Ade Yanti Nurfaidah ◽

Dheana Putri Lestari ◽

Rheisya Talitha Azzahra ◽

Dian Ratna Suminar

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Sulfuric Acid ◽

Atmospheric Pressure ◽

Operating Temperature ◽

Acid Leaching ◽

X Ray Diffraction ◽

X Ray ◽

Pressure Acid Leaching ◽

Scanning Electron

Abstrak Nikel merupakan unsur logam yang penggunaannya sudah dikenal dalam industri, terutama pada pelapisan logam dan paduan. Pengolahan nikel dari bijih nikel laterit (jenis Limonit) menggunakan proses hidrometalurgi Atmospheric Pressure Acid Leaching (APAL) yang dinilai lebih ekonomis karena pemakaian energi dan biaya operasional cukup rendah. Media pelarut yang digunakan berupa larutan asam sulfat (H2SO4). Sebelum dilakukan pengolahan, karakterisasi bijih dilakukan menggunakan X-Ray Diffraction (XRD), X-Ray Flourscence (XRF), dan Scanning Electron Microscopy (SEM). Metode penelitian yang dilakukan yaitu literature review. Hasil review dari beberapa artikel jurnal menunjukkan bahwa kadar nikel yang terkandung pada suatu bijih sekitar 1,42%, 2,94 dan 0,95% serta sisanya adalah pengotor. Kondisi operasi yang tepat akan menghasilkan pemurnian nikel yang cukup tinggi. Parameter kondisi operasi yang dapat memengaruhi proses pemisahan nikel diantaranya suhu operasi yang ditunjukan dengan semakin meningkatnya % ekstraksi nikel seiring dengan kenaikan suhu. Selain suhu operasi, konsentrasi pelarut juga salah satu parameter yang mempengaruhi % ekstraksi karena semakin tinggi ion H+ akan memudahkan proses pelarutan sehingga akan mengikat Nikel Oksida yang terdapat pada bijih. Suhu paling optimal untuk menghasilkan nikel dengan kemurnian tinggi dalam operasi pelindian atmosferik adalah 90°C dan konsentrasi asam sulfat 5 M. Kata Kunci: Nikel, pelindian, suhu, konsentrasi Abstract Nickel is a metal element whose use is well known in industry, especially in metal and alloy plating. The processing of nickel from laterite nickel ore (Limonite type) uses a hydrometallurgical process of Atmospheric Pressure Acid Leaching (APAL) which is considered more economical because energy consumption and operational costs are quite low. The solvent medium used is a solution of sulfuric acid (H2SO4). Prior to processing, ore characterization was carried out using X-Ray Diffraction (XRD), X-Ray Flourscence (XRF), and Scanning Electron Microscopy (SEM). The research method literature review article. The results of reviews from several journal articles show that the nickel content contained in an ore is around 1.42%, 2.94% and 0.95% and the rest is impurity. The right operating conditions will result in relatively high nickel refining. The operating condition parameters that can affect the nickel separation process include the operating temperature which is indicated by the increasing % nickel extraction along with the increase in temperature. In addition to operating temperature, solvent concentration is also one of the parameters that affects the% extraction because the higher the H+ ion will facilitate the dissolving process so that it will bind to the Nickel Oxide contained in the ore. The optimal temperature to produce high-purity nickel in atmospheric leaching operations is 90°C and a sulfuric acid concentration of 5 M. Keywords: Nickel, leaching, temperature, concentration

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COMPOSITION, STRUCTURE AND TEXTURAL CHARACTERISTICS OF DOMESTIC ACID ACTIVATED BENTONITE

Contemporary Materials ◽

10.7251/comen1401133p ◽

2014 ◽

Vol 5 (1) ◽

Author(s):

Zоrаn Pеtrоvić ◽

Pеrо Dugić ◽

Vојislаv Аlеksić ◽

Sаbinа Bеgić ◽

Vlаdаn Мićić ◽

...

Keyword(s):

Sulfuric Acid ◽

Low Temperature ◽

Layered Structure ◽

Nitrogen Adsorption ◽

X Ray Diffraction ◽

Textural Characteristics ◽

X Ray ◽

Before And After ◽

Activated Bentonite ◽

Composition Structure

Bentonites are aluminosilicate minerals which, due to their porosity, layered structure and composition have a wide application. Structural and textural characteristics of bentonite may be improved by different modification procedures. The aim of this study was to investigate compositional, structural and textural characteristics of domestic bentonite in place Gerzovo, before and after the activation with sulfuric acid. These characteristics were investigated by analytical methods, X-ray diffraction (XRD) and the method of low-temperature nitrogen adsorption (BET). Characteristics of acid-activated bentonite were compared with the characteristics of commercial active clay. The obtained results showed that the activation of bentonite with sulfuric acid leads to a significant improvement in structural and textural characteristics. Using these results it can be assumed that this bentonite will have good adsorption characteristics and can serve as an alternative in comparison with imported commercial aluminosilicate-based adsorbents.

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Phase characterisation of TiO/sub 2/ thin films using micro-Raman spectroscopy and glancing angle X-ray diffraction

2002 Conference on Optoelectronic and Microelectronic Materials and Devices. COMMAD 2002. Proceedings (Cat. No.02EX601) ◽

10.1109/commad.2002.1237222 ◽

2005 ◽

Cited By ~ 1

Author(s):

J. Hugmann ◽

B.S. Richards ◽

A. Crosky

Keyword(s):

Thin Films ◽

Raman Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Micro Raman Spectroscopy ◽

Glancing Angle

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Corrosion Performance of TRIP Steels under Atmospheric Environment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.960.3 ◽

2019 ◽

Vol 960 ◽

pp. 3-8

Author(s):

Hao Xu Wang ◽

Yi Qin Cai ◽

Zhuang Li ◽

Qi Zhou

Keyword(s):

Trip Steel ◽

Atmospheric Corrosion ◽

Alloying Elements ◽

Atmospheric Environment ◽

Protective Mechanism ◽

Corrosion Performance ◽

X Ray Diffraction ◽

X Ray ◽

Trip Steels ◽

Surface Morphologies

Atmospheric corrosion test of TRIP steels was conducted in laboratory. The surface morphologies of the specimens were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and electro-probe microanalysis (EPMA). Corrosion performance of TRIP steels under atmospheric environment was investigated by discussing the protective mechanism. The corrosion rates of steel A are significantly greater than steel B in atmospheric environment tests. The enhancement of corrosion performance of TRIP steel is attributed to the additions of alloying elements, such as P, Cr, Cu, and Ni etc.. The alloying elements increase the compactness and densification of rust layers. Electrochemical characteristic of TRIP steel is improved by means of the enhancement of the thermodynamic stability.

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Combined synchrotron x-ray diffraction and micro-Raman for following in situ the growth of solution-deposited YBa2Cu3O7 thin films

Journal of Materials Research ◽

10.1557/jmr.2005.0421 ◽

2005 ◽

Vol 20 (12) ◽

pp. 3270-3273 ◽

Cited By ~ 3

Author(s):

F. Berberich ◽

H. Graafsma ◽

B. Rousseau ◽

A. Canizares ◽

R. Ramy Ratiarison ◽

...

Keyword(s):

Raman Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Additional Information ◽

Micro Raman Spectroscopy ◽

High Temperature Process ◽

Structural Growth ◽

Metal Organic ◽

Insight Into

A unique combination of in situ synchrotron x-ray diffraction and in situ micro-Raman spectroscopy was used to study the growth process of YBa2Cu3O6+x films obtained by metal organic decomposition using trifluoroacetate precursor on LaAlO3 substrates. The techniques give complementary information: x-ray diffraction gives insight into the structural growth, whereas micro-Raman spectroscopy gives information of the chemical composition with additional information on the texture. To perform both experiments in situ, a special high-temperature process chamber was designed.

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Baeyer-Villiger Oxidation of 10-Methyl-9-Anthraldehyde: Formation and Photochemical Dimerization of 9-Formyloxy-10-methylanthracene

Australian Journal of Chemistry ◽

10.1071/ch9881977 ◽

1988 ◽

Vol 41 (12) ◽

pp. 1977 ◽

Cited By ~ 1

Author(s):

HD Becker ◽

BW Skelton ◽

AB Turner ◽

AH White

Keyword(s):

Molecular Structure ◽

Hydrogen Peroxide ◽

Acetic Acid ◽

Sulfuric Acid ◽

Diffraction Study ◽

Crystalline State ◽

X Ray Diffraction ◽

X Ray ◽

Tail Structure ◽

Villiger Oxidation

Oxidation of 10-methyl-9-anthraldehyde with hydrogen peroxide in acetic acid in the presence of sulfuric acid gives 9-formyloxy-10-methylanthracene which dimerizes in solution upon exposure to light. The head-to-tail structure of the 4π+4π photodimer was established by a single-crystal X-ray diffraction study. In the crystalline state, the molecular structure is centrosymmetric, and the length of the photochemically formed bonds 1.646(4)Ǻ. Crystals are monoclinic, P21/c, a 7.980(5), b 16.143(7), c 9.571(3)Ǻ, β 114.38(3)°, Z=2 dimers; R was 0.041 for 1362 'observed' diffractometer reflections.

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The Effect of Ru on Unsupported Pt-Ru Alloys for Methanol Electro-Oxidation at Different Temperatures

MRS Proceedings ◽

10.1557/proc-393-25 ◽

1995 ◽

Vol 393 ◽

Author(s):

Deryn Chu ◽

Charles Walker ◽

Sol Gilman

Keyword(s):

Cyclic Voltammetry ◽

Sulfuric Acid ◽

Surface Area ◽

Hydrogen Adsorption ◽

X Ray Diffraction ◽

X Ray ◽

Different Temperatures ◽

Adsorption Surface ◽

Electro Oxidation ◽

Bulk Alloys

ABSTRACTUnsupported different atomic ratios of platinum-ruthenium bulk alloys were prepared. The alloys were characterized by cyclic voltammetry, X-ray diffraction and energy dispersive X-ray spectroscopy. These alloys were also tested as anodes for methanol electro-oxidation in sulfuric acid over a range of temperatures. Ruthenium is inactive for methanol electro-oxidation at 25 °C, but becomes active at higher temperatures. When a comparison is made on the basis of “true” (hydrogen adsorption) surface area, a 30 atomic percent Ru electrocatalyst provides the highest activity for methanol electro-oxidation as measured at either 0.4 or 0.5V vs. RHE at both 25 and 60 °C.

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