The Influence of Archaeometallurgical Copper Alloy Castings Microstructure towards Corrosion Evolution in Various Corrosive Media

The local patterns at the interfaces of corrosion stratification, developed on two archaeometallurgical bronzes (a Cu-Sn-Pb and a Cu-Zn-Sn-Pb alloy), in the as-cast condition, were assessed by OM and SEM-EDS systematic elemental chemical analyses. Previously, the alloys—whose metallurgical features and electrochemical behaviour were already well studied—have been subjected to laboratory corrosion experiments. The corrosion procedures involved electrochemical anodic polarization experiments in various chloride media: 0.1 mol/L NaCl, 0.6 mol/L NaCl and two other synthetic chloride-containing solutions, representing electrolytes present in marine urban atmosphere and in the soil of coastal sites. The characterization of the Cu-Sn-Pb alloy electrochemical patinas after anodic sweep (OCP+ 0.6 V) revealed that the metal in all electrolytes undergoes extensive chloride attack and selective dissolution of copper which initiates from the dendritic areas acting as anodic sites. The most abundant corrosion products identified by FTIR in all electrochemical patinas were Cu2(OH)3Cl), Cu2(OH)2CO3 and amorphous Cu and Sn oxides. The characterization of the Cu-Sn-Pb alloy electrochemical patina after slow anodic sweep (OCP+ 1.5 V) in 0.1 mol/L NaCl reveals selective oxidation of dendrites and higher decuprification rate in these areas. Corrosion products of Sn-rich interdendritic areas are dominated by oxygen species (oxides, hydroxides, hydroxyoxides) and Cu-rich dendrites by chlorides. In the case of Cu-Zn-Sn-Pb, Zn in dendritic areas is preferentially attacked. The alloy undergoes simultaneous dezincification and decuprification, with the former progressing faster, especially in dendritic areas. The two processes at the alloy/patina interface leave behind a metal surface where α-dendrites are enriched in Sn compared to the alloy matrix. The results of this study highlight the dynamic profile of corrosion layer build-up in bronze and brass. Moreover, the perception of the dealloying mechanisms progression on casting features, at mid-term corrosion stages, is extended.

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TRIBALOY 400

Alloy Digest ◽

10.31399/asm.ad.co0072 ◽

1975 ◽

Vol 24 (7) ◽

Keyword(s):

Alloy Powder ◽

Base Alloy ◽

Intermetallic Phase ◽

Heat Treating ◽

Corrosion And Wear ◽

Corrosive Media ◽

Alloy Matrix ◽

Cobalt Base Alloy ◽

Plasma Sprayed ◽

Cobalt Base

Abstract TRIBALOY 400 consists of a hard, intermetallic phase in a softer, cobalt-base alloy matrix. It can be cast or hardfaced. As alloy powder it can be plasma sprayed or blended with other powders for P/M (Powder/Metallurgy) processing. Uses include anti-wear surfaces and bearings or seals operating in corrosive media. This datasheet provides information on composition, physical properties, hardness, tensile properties, and compressive strength as well as fracture toughness. It also includes information on corrosion and wear resistance as well as forming, heat treating, machining, and joining. Filing Code: Co-72. Producer or source: Tribaloy Products.

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Mechanical characterization of LM25 alloy matrix composite reinforced with boron carbide

Journal of Composite Materials ◽

10.1177/00219983211005513 ◽

2021 ◽

pp. 002199832110055

Author(s):

Zeeshan Ahmad ◽

Sabah Khan

Keyword(s):

Tensile Strength ◽

Boron Carbide ◽

Mechanical Characterization ◽

Stir Casting ◽

Surface Mapping ◽

Alloy Matrix ◽

Casting Technique ◽

The Matrix ◽

Carbide Particles

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.

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Stable isotopic characterization of nitrate wet deposition in the tropical urban atmosphere of Costa Rica

Environmental Science and Pollution Research ◽

10.1007/s11356-021-15327-x ◽

2021 ◽

Author(s):

Mario Villalobos-Forbes ◽

Germain Esquivel-Hernández ◽

Ricardo Sánchez-Murillo ◽

Rolando Sánchez-Gutiérrez ◽

Ioannis Matiatos

Keyword(s):

Costa Rica ◽

Wet Deposition ◽

Urban Atmosphere ◽

Stable Isotopic ◽

Isotopic Characterization

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Characterization of corrosion products on archaeological iron coins

Anti-Corrosion Methods and Materials ◽

10.1108/00035591111097693 ◽

2011 ◽

Vol 58 (1) ◽

pp. 39-45 ◽

Cited By ~ 1

Author(s):

Guo Cheng Lv ◽

Zi Se Wang ◽

Li Mei Wu ◽

Chunchun Xu

Keyword(s):

Corrosion Products ◽

Archaeological Iron

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Production and mechanical characterization of Ni-coated carbon fibers reinforced Al-6063 alloy matrix composites

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2019.02.043 ◽

2019 ◽

Vol 787 ◽

pp. 543-550 ◽

Cited By ~ 14

Author(s):

Anıl Alten ◽

Eray Erzi ◽

Özen Gürsoy ◽

Gökçe Hapçı Ağaoğlu ◽

Derya Dispinar ◽

...

Keyword(s):

Carbon Fibers ◽

Mechanical Characterization ◽

Matrix Composites ◽

Alloy Matrix ◽

Coated Carbon

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Morphological, chemical and optical absorbing characterization of aerosols in the urban atmosphere of Valladolid

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-2739-2005 ◽

2005 ◽

Vol 5 (10) ◽

pp. 2739-2748 ◽

Cited By ~ 11

Author(s):

S. Mogo ◽

V. E. Cachorro ◽

A. M. de Frutos

Keyword(s):

Mass Fraction ◽

Fine Particles ◽

Aerosol Particles ◽

Cascade Impactor ◽

Urban Atmosphere ◽

Coarse Particles ◽

X Ray ◽

Illumination System ◽

Inverse Power Law

Abstract. Samples of atmospheric aerosol particles were collected in Valladolid, Spain, during the winter of 2003-2004. The measurements were made with a Dekati PM10 cascade impactor with four size stages: greater than 10 µm, between 2.5 to 10 µm, 1 to 2.5 µm and less than 1 µm. The size and shape of the particles were analyzed with a scanning electron microscope (SEM) and elemental analysis was done with an energy dispersive x-ray analysis (EDX). We present an evaluation by size, shape and composition of the major particulate species in the Valladolid urban atmosphere. The total aerosol concentration is very variable, ranging from 39.86 µg·m-3 to 184.88 µg·m-3 with the coarse particles as the dominant mass fraction. Emphasis was given to fine particles (<1 µm), for which the visible (400 nm to 650 nm) light absorption coefficients were measured using the integrating plate technique. We have made some enhancements in the illumination system of this measurement system. The absorption coefficient, σa, is highly variable and ranges from 7.33×10-6 m-1 to 1.01×10-4 m-1 at a wavelength of 550 nm. There is an inverse power law relationship between σa and wavelength, with an average exponent of -0.8.

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Corrosion Products Electrochemical Behaviour into Molten LiF-NaF: Investigation of Cr(II) System

Journal of The Electrochemical Society ◽

10.1149/1945-7111/abe088 ◽

2021 ◽

Vol 168 (2) ◽

pp. 026510

Author(s):

L. Massot ◽

M. Gibilaro ◽

D. Quaranta ◽

P. Chamelot

Keyword(s):

Electrochemical Behaviour ◽

Corrosion Products

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Characterization of nighttime formation of particulate organic nitrates based on high-resolution aerosol mass spectrometry in an urban atmosphere in China

10.5194/acp-2018-1009 ◽

2018 ◽

Author(s):

Kuangyou Yu ◽

Qiao Zhu ◽

Ke Du ◽

Xiao-Feng Huang

Keyword(s):

High Resolution ◽

Factorization Method ◽

Urban Atmosphere ◽

Ozone Production ◽

Urban Site ◽

High Time Resolution ◽

Organic Nitrates ◽

Aerosol Mass ◽

Polluted Atmosphere

Abstract. Organic nitrates are important atmospheric species that significantly affect the cycling of NOx and ozone production. However, characterization of particulate organic nitrates and their sources in inorganic nitrate-abundant particles in polluted atmosphere is a big challenge, and has been little performed in the literature. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed at an urban site in South China from 2015 to 2016 to characterize particulate organic nitrates with high time resolution. Based on two different data processing methods, 13–21 % of the total measured nitrates was identified to be organic nitrates in spring, 41–64 % in summer and 16%–25 % in autumn; however, in winter, most measured nitrates were inorganic. The good correlation between organic nitrates and fresh secondary organic aerosol identified by the positive matrix factorization method at night rather than in the daytime indicated a potentially important role of nighttime secondary formation. Therefore, we theoretically estimated nighttime NO3 radical concentrations and SOA formation using the various VOCs measured simultaneously. Consequently, the calculated products of monoterpene reacting with NO3 agreed well with the organic nitrates in terms of both concentration and variation, suggesting that the biogenic VOC reactions with NO3 at night are the dominant formation pathway for particulate organic nitrates in polluted atmosphere, despite of much higher abundance of anthropogenic VOCs.

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