Development Of Corrosion Products Research Articles

An integrated investigation of the crystalline, rheological and physical properties of corrosion products in cementitious materials

This paper discusses the behaviour of the rheological behaviour of corrosion products (produced in the laboratory) in a high alkaline environment to understand hydraulic-induced fracture by corrosion products in reinforced concrete. A mixture of iron powder, sodium chloride, calcium hydroxide, and water was used to produce corrosion products. The development of corrosion products was studied at 2, 4, 6, and 8-week intervals. Imaging techniques, along with rheological characterization methods, were conducted to understand the viscoelastic flow behaviour of corrosion products. The results show that corrosion products exhibited different rheologic properties throughout the corrosion process. Three iron oxide phases (Magnetite, Goethite, and Lepidocrocite) were detected throughout the initiation and propagation stages of corrosion in the laboratory. The corrosion products obtained for each study period behaved as colloidal materials, demonstrating all the characteristics of shear-thinning materials. As a result of chemical and particle disintegration, the viscosity of corrosion products decreased with the applied shear rate. In addition, the experimental data showed that the density and particle size of corrosion products decreased with time. These results can be used to understand the progress of corrosion's damage in reinforced concrete.

Corrosion Damage to Joints of Lattice Towers Designed from Weathering Steels

The article dealt with the load-bearing capacity and durability of power line lattice towers designed from weathering steel. Attention was paid in particular to the bolted lap joints. The article evaluates the static and corrosion performance of bolted lap joints in long-term operating towers, and also presents and evaluates design measures that can be applied in the design of new lattice towers, or in the reconstruction of already operating structures. Power line lattice towers are the most extensive realization of weathering steel in the Czech Republic. On the basis of the inspections carried out to evaluate the working life of the transmission towers in operation, it can be stated that a sufficiently protective layer of corrosion products generally developed on the bearing elements of the transmission towers. However, the development of crevice corrosion at the bolted joints of the leg members is a significant problem. In this paper, the corrosion damage of bolted joints was evaluated considering two basic aspects: (1) the influence of crevice corrosion on the bearing capacity of the bolted joint was evaluated, using experimental testing and based on analytical and numerical calculations; (2) appropriate design measures applicable to the rehabilitation of developed crevice corrosion of in-service structures, or the elimination of crevice corrosion in newly designed lattice towers, was evaluated. Calculation analyses and destructive tests of bolted joints show that the development of corrosion products in the crevice does not have a significant effect on the bearing capacity of the joint, provided that there is no significant corrosion weakening of the structural elements, and bolts of class 8.8 or 10.9 are used. The results of the long-term experimental programme, and the experience from the rehabilitations carried out, show that, thanks to appropriate structural measures, specified in detail in the paper, the long-term reliable behaviour of the lattice towers structures is ensured.

Corrosive Environment Factors and their Influence on the Development of Weathering Steel Corrosion Products

This article deals with the topic of atmospheric corrosion. Atmospheric corrosion causes damage to nearly 80% of all existing steel structures. The main parameters of atmospheric corrosion are the time of wetness (TOW), air temperature and aggressive corrosive agents such as chlorides, sulfur dioxide and others. Currently, low alloy steels with improved atmospheric corrosion resistance called weathering steels are used for the steel structures located in outdoor environment. A protective layer of corrosion products is created on the steel surface and this layer can reduce continuation of corrosion of steel. The time of wetness together with the effect of aggressive corrosive agents are various for surfaces oriented vertically or horizontally. Experimental tests of atmospheric weathering steel were carried out to monitor the impact of location and position of surface on the different constructions. These tests allow monitoring the development of corrosion products in real exposures. The article presents a part of the research, which includes monitoring the development of the thickness of corrosion products with regard to the position on the structure. Research is developed to refine of prediction models with the aim of improving determination of corrosion losses during the service life of the structure. Second part of these experiments is dedicated to measuring the deposition rate of chlorides. Chlorides have a corrosive impact on the steel surface. Under normal conditions the chlorides does not create suitable environment for the development of a protective layer of corrosion products.

Corrosion Processes on Weathering Steel Bridges Influenced by Deposition of De-Icing Salts.

The safety and durability of bridges designed from weathering steels are conditioned by the development of a sufficiently protective layer of corrosion products. Air pollution, microclimate around the bridge, time of wetness, structural solution of the bridge, and the position and orientation of the surface within the bridge structure all influence the development of protective layers on the surface of the weathering steel. In this article, attention is focused mainly on the microclimatic effects resulting from the road traffic under the bridge. The influence of chloride deposition on the development of corrosion products is evaluated using experimental in situ testing. Two neighboring bridges made of weathering steel and crossing different types of obstacles were selected for this experiment. Relations and dependences between the measured parameters (deposition rate of chlorides, corrosion rates, thickness of corrosion products and the amount of chlorides in corrosion products) are evaluated and discussed.

Identification of corrosion products and 3D distribution in reinforced concrete using X-ray micro computed tomography

Abstract The main purpose of this study is to non-destructively monitor the formation and development of corrosion products in reinforced mortar with the help of X-ray micro computed tomography (X-ray µCT). A new method based on the relationship between the linear attenuation coefficient and CT number as well as greyscale value is built to identify different type of corrosion products. Based on this method, two categories of corrosion products including iron oxides and iron hydroxides are identified in this research. Additionally, the corrosion mechanism and the interaction between different types of corrosion products are discussed according to the characteristics of corrosion evolution. Furthermore, the volumetric expansion ratio of corrosion products is quantified (from 2.71 to 3.97). This method provides a new angle to investigate the formation and development of reaction products, which contributes to further understand the corrosion process in reinforced concrete.

Long-Term Atmospheric Corrosion of Hot-Dip Galvanized Steel and Zn-Al Coated Steel

Hot dip galvanized steel and zinc alloyed coated steel such as ZnAl are widely used in the building industry. However, despite large efforts made to study the corrosion products formed on zinc under atmospheric weathering conditions (see for instance reference 1 and 2), very few data exist on HDG and zinc alloyed coated steel [5]. This work is a part of a larger research program were steel with different zinc coatings are exposed on a worldwide basis on well characterized exposure sites in Europe, Asia and North America, see Table 1. Corrosion rates of hot dip galvanized steel and zinc aluminum coated steel (e.g. Zn5%Al and Zn 55% Al) were determined after 1, 2, 4 and 6 years of exposure under different climatic conditions. The formation and development of corrosion products was followed by detailed analysis of samples exposed 0.5, 1, 2, 4 and 6 years using XRD, FTIR-spectroscopy and SEM-EDS. The data are discussed in view of current knowledge in the atmospheric corrosion of zinc, HDG and Zn-Al coated steel materials [1-6] Table 1. Test sites in the exposure program Code Name Country Distance to Sea(m) A Brest France <5 B Bohus-Malmön (I) Sweden <5 C Bohus-Malmön (II) Sweden 300 D Ijmuiden Netherlands 2600 E Cadiz Spain 750 F Jiangjin China ̴900 km G Ostrawa Czech Republic ̴500 km H Dubai UAE 2000 I Daytona Beach USA 100 J Quindao China 10 K Wanning China 100 L Bangkok Thailand 35 km M Sattahip Thailand 10 N Singapore SIngapore 10 References 1-I. Odnevall, C. Leygraf, Corros. Sci. 34 (1993) 1213–1229. 2- I. Odnevall, C. Leygraf, Corros. Sci. 36 (1994) 1551–1567. 3- N. Le Bozec, D. Thierry, M. Rohwerder, Dan Persson, G. Luckeneder and L. Luxem, Effect of CO2 on the atmospheric corrosion of ZnMgAl coated steel, Corrosion Science, 74, pp 379-386, 2013 4- E. Diller, B. Lescop, S. Rioual, G Nguyen, D. Thierry and B. Rouvello, Initial formation of corrosion products on pure zinc and MgZn2 examined by XPS: Corrosion Science 79, pp 83-88, 2014. 5- D. Persson, N. Le Bozec, T. Prosek, D. Thierry, G. Luckenader , Corrosion Science Vol 90, pp 276-283, 2015. 6- D. Persson, D. Thierry, N. Le Bozec: Corrosion products formation on Zn55Al upon exposure in marine atmosphere, Corrosion Science, 720, 2011.

Characterization of Corrosion Products on Weathering Steel Bridges Influenced by Chloride Deposition

The article presents the results of experimental testing of corrosion processes on weathering steel bridges. Two bridge structures spanning various obstacles were selected for the experimental measurement. The tested bridges are situated in the same location and structural solution of these bridges is similar. Differences in development of corrosion products are mainly affected by the microclimate below the bridge structure. Special attention is paid to a bridge over the motorway which is strongly affected by the deposition of chlorides. The dependences between the measured deposition of chlorides and parameters of corrosion layers (thickness of corrosion products, corrosion rates, and chemical composition) are discussed and evaluated in this article.

Influence of Chloride Deposition on Corrosion Products

The article deals with the influence of atmospheric corrosion and corrosive environment factors on the development of a protective layer of corrosion products of the weathering steel. The main aggressive factors of atmosphere that can negatively affect corrosion rate and the development of corrosion products on the steel surface include sulfates and chlorides. The development of the protective layer of corrosion products on bridge structures designed from weathering steel is monitored by program of experimental atmospheric corrosion tests. Exposed specimens on selected bridges allow to determine the relationship between the thickness of the layer of corrosion products and corrosion losses depending on the time of exposure and local environmental conditions. For the evaluation of protective properties of corrosion layer of the weathering steel indexes PAI is applied. This article presents the part of results of field experimental atmospheric corrosion tests for selected bridge structures in Ostrava. The influence of the amount of chlorides forming insoluble compounds in corrosion products on the protective properties of corrosion layers weathering steel is monitored for these bridges.

(Invited) Atmospheric Corrosion of Zinc Magnesium Aluminum Coated Steel

Hot dip galvanized steel and zinc alloyed coated steel such as ZnAl and ZnAlMg (ZM) are used in the building industry and in the automotive industry. However, In the case of zinc coated steel with Al and Mg, there is still relatively scarce information on the long term performance under atmospheric weathering conditions. Although large efforts have been made to study the corrosion products formed on zinc under atmospheric weathering conditions (see for instance reference 1 and 2), very few data exist on HDG and zinc alloyed coated steel [5]This work is a part of a larger research program were steel with different zinc coatings are exposed on a worldwide basis on well characterized exposure sites in Europe, Asia and North America, see table 1. Corrosion rates of hot dip galvanized steel and zinc magnesium aluminum (e.g. 2% w% of Al and 2w% of Mg) coated steel were determined after 1, 2 and 4 years of exposure under different climatic conditions. The formation and development of corrosion products was followed by detailed analysis of samples exposed 0.5, 1, 2 and 4 years using XRD, FTIR-spectroscopy and SEM-EDS. For HDG the sulphate/carbonate ratio was highly dependent on the exposure site (with low values at marine sites and high values at industrial sites). A model of initiation and propagation of local corrosion on HDG has been proposed. The analyses of corrosion products on ZM coated steel revealed higher sulphate/carbonate ratio compared to HDG. This may be linked to the corrosion rate of the coating with less formation of hydrozincite.The data are discussed in view of current knowledge in atmospheric corrosion of zinc, HDG and ZM coated steel materials [1-6] Table 1. Test sites in the exposure program Code Name Country Distance to Sea(m) A Brest France <5 B Bohus-Malmön (I) Sweden <5 C Bohus-Malmön (II) Sweden 300 D Ijmuiden Netherlands 2600 E Cadiz Spain 750 F Jiangjin China ̴900 km G Ostrawa Czech Republic ̴500 km H Dubai UAE 2000 I Daytona Beach USA 100 J Quindao China 10 K Wanning China 100 L Bangkok Thailand 35 km M Sattahip Thailand 10 N Singapore SIngapore 10 References1-I. Odnevall, C. Leygraf, Corros. Sci. 34 (1993) 1213–1229.2- I. Odnevall, C. Leygraf, Corros. Sci. 36 (1994) 1551–1567.3- N. Le Bozec, D. Thierry, M. Rohwerder, Dan Persson, G. Luckeneder and L. Luxem, Effect of CO2 on the atmospheric corrosion of ZnMgAl coated steel, Corrosion Science, 74, pp 379-386, 2013 4- E. Diller, B. Lescop, S. Rioual, G Nguyen, D. Thierry and B. Rouvello, Initial formation of corrosion products on pure zinc and MgZn2 examined by XPS: Corrosion Science 79, pp 83-88, 2014.5- D. Persson, N. Le Bozec, T. Prosek, D. Thierry, G. Luckenader , Corrosion Science Vol 90, pp 276-283, 2015.6- D. Persson, D. Thierry, N. Le Bozec: Corrosion products formation on Zn55Al upon exposure in marine atmosphere, Corrosion Science, 720, 2011.

Atmospheric Corrosion of Zinc Coated Steel- Results from a Worldwide Outdoor Exposure Program

In the last decades, numerous national or international exposure programs have been launched to collect data on atmospheric corrosion rates and to establish prediction tools for atmospheric corrosion of metallic structures [1]. Most commonly, carbon steel, zinc, copper and aluminum samples are exposed in selected locations for a year or more. Based on weight loss measurements, dose-response functions and corrosivity maps have been compiled [2,3]. A major limitation of most previous studies is that data have been acquired mainly for bulk metals while studies on metallic coatings are rare. Similarly, the evolution of corrosion products with exposure time has been studied for bulk zinc [4] but few studies on zinc coated steel is reported. This work is a part of a larger research program were steel with different zinc coatings are exposed on a worldwide basis on well characterized exposure sites in Europe, Asia and North America, see table 1. Corrosion rates of HDG were determined after exposure under different climatic conditions. Corrosion rates for HDG after two years exposure have been measred. Uniformity of the coating corrosion and performance at cut edges was evaluated. The effect of sample orientation and sheltering was investigated. Correlation of data on mass loss with environmental data collected at the exposures sites enabled the derivation of dose-response function HDG. The formation and development of corrosion products was followed by detailed analysis of samples exposed 0.5, 1 and 2 years using XRD, FTIR-spectroscopy and SEM-EDS. The main corrosion products formed on HDG on the different sites are Zn5(OH)6(CO3)2, NaZn4(SO4)(OH)6Cl·6H2O, (Zn(OH)2)3 ZnSO4·5H2O and Zn5(OH)8Cl2·H2O. The type and relative amounts of different corrosion products were related to the location and type of exposure site but no systematic changes were observed with the time of exposure. Table 1. Test sites in the exposure program Code Name Country Distance to Sea(m) A Brest France <5 B Bohus-Malmön (I) Sweden <5 C Bohus-Malmön (II) Sweden 300 D Ijmuiden Netherlands 2600 E Cadiz Spain 750 F Jiangjin China ̴900 km G Ostrawa Czech Republic ̴500 km H Dubai UAE 2000 I Daytona Beach USA 100 J Quindao China 10 K Wanning China 100 L Bangkok Thailand 35 km M Sattahip Thailand 10 N Singapore SIngapore 10 References 1- D. Knotkova, V. Kucera, P. Boschek: ASTM STP 1421 Outdoor Atmospheric Corrosion, pp.107, 2002 2- A. Mikhailov, J. Tidblad and V. Kucera: Protection of Metals, 40(6),pp 541-550, 2004 3- M. Morcillo, E. Almeida, B. Chico, D. De la Fuente Analysis of ISO Standard 9223 (Classification of Corrosivity of Atmospheres) in the Light of Information Obtained in the Ibero-American Micat, ASTM STP 1421 Outdoor Atmospheric Corrosion, 2002, pp. 59. 4. I. Odnevall, C. Leygraf, Atmospheric Corrosion, ASTM STP 1239, ASTM, Philadelphia, 1995, pp. 215–229

Corrosion of cadmium plating by runway de-icing chemicals: Study of surface phenomena and comparison of corrosion tests

In this paper, we study the corrosion of cadmium plating by four runway de-icing chemicals using electrochemical measurements and standard (immersion) and proposed (cyclic) runway de-icing corrosion tests for cadmium plating. Besides the obtained electrochemical and gravimetric data, we analyze the exposed surfaces by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and infra-red spectroscopy (IR). The chemicals included in the tests are pure potassium formate, pure potassium acetate and the corresponding commercial chemicals.Examinations revealed two parallel and linked phenomena on the plating surface, i.e., anodic dissolution of cadmium and development of corrosion products, primarily cadmium carbonate, CdCO3. Electrochemical measurements disclosed that the formed corrosion products slightly improved corrosion resistance of the surface but definitely did not stop corrosion completely, probably due to discontinuous structure. As for the studied de-icing chemicals, potassium formates systematically introduced more segmented corrosion products than potassium acetates and, subsequently, more severe corrosion on the specimens. Immersion cadmium corrosion test did not give very reliable results due to relatively low introduced corrosion rates and very large occasional scatter in the results. Cyclic cadmium corrosion tests introduced relatively greater corrosion rates and somewhat lower deviations than the immersion test, being hence, more reliable, but also more challenging in terms of meeting the weight change criteria for passing the test.

Corrosion Products and Formation Mechanism During Initial Stage of Atmospheric Corrosion of Carbon Steel

The formation and development of corrosion products on carbon steel surface during the initial stage of atmospheric corrosion in a laboratory simulated environment have been studied by scanning electron microscopy (SEM) and Raman spectroscopy. The results showed that two different shapes of corrosion products, that is, ring and chain, were formed in the initial stage of corrosion. MnS clusters were found in the nuclei of corrosion products at the active local corrosion sites. The ring-shaped products were composed of lepidocrocite (γ-FeOOH) and maghemite (γ-Fe 2 O 3) transformed from lepidocrocite. The chain-type products were goethite (α-FeOOH). A formation mechanism of the corrosion products is proposed.

Transmission Mössbauer Analysis of Nanophased Oxides Formed on High Strength Steels

Nanophased oxides found in the corrosion coatings of atmospherically weathered steels have properties that are scientifically significant and industrially important. Mossbauer spectroscopy proves to be a very useful tool to accurately characterize the corrosion coatings. Samples of carbon steel were exposed in Campeche, along the Gulf of Mexico for up to one year and the development of corrosion products as a function of steel type and exposure time were studied using Mossbauer spectroscopy, micro-Raman spectrometry and X-ray diffraction. Both X-ray diffraction and transmission Mossbauer spectroscopic results indicated that lepidocrocite, maghemite and goethite were the dominant oxides. Transmission Mossbauer analysis at 77 K indicated that for up to three months of exposure, lepidocrocite and maghemite accounted for nearly 80% of the relative amount, with goethite contributing only 20% to the mixture. However, as the exposure time increased to 6 months, the relative contribution of goethite increased at the expense of decreasing amounts of maghemite. Monitoring the environment during the exposure time indicated that the average time of wetness decreased. The decrease in the relative contribution of maghemite to the total oxide concentration is related to the decreasing time of wetness, with increasing exposure time.

Atmospheric Corrosion of Zinc in the Presence of Ammonium Sulfate Particles

The atmospheric corrosion of zinc in the presence of particles has been investigated at 300 and 373 K in air‐water vapor mixtures. The development of corrosion products was followed by several in situ techniques, including Fourier transform infrared spectroscopy, x‐ray diffraction, pH measurements, and scanning Kelvin probe measurements. Unlike earlier work on copper and aluminum, zinc reacts with the particles below the critical relative humidity (CRH) of . At 300 K reaction was observed at 65% relative humidity (RH), but not at 60% RH. This is attributed to the presence of basic zinc carbonate on the surface, which absorbs sufficient water at this low RH to make electrochemical reactions possible. At and above the CRH of , zinc reacts with forming mixed ammonium zinc sulfate and later on basic zinc sulfate, and at 373 K additionally zincite (ZnO). Above the CRH of , the corrosion potential decreases directly after formation of droplets surrounding the particles and zinc becomes active. Corrosion mechanisms are proposed to explain the observations.

Electrochemical monitoring of aluminium corrosion in a cyclic atmospheric test chamber

Abstract A three electrode probe, comprising an aluminium electrode of interest with surrounding graphite half rings, has been employed to study the corrosion behaviour of aluminium in an atmospheric test chamber, using a mixed salt spray with wet/dry cycling. The potential response of the probe reveals four distinct regions associated with initial wetting, the presence of a continuous electrolyte film, and initial and final drying. Understanding of the potential response, in terms of the corrosion behaviour of aluminium, is assisted by the use of intermittent polarization, whereby aluminium is transiently connected to one graphite electrode. Thus, localized corrosion initiates in the misting periods with enhanced corrosion in the early stages of electrolyte solution concentration through drying. Development of corrosion products in the concentrating. electrolyte solution probably hinders further corrosion at such sites. On the other hand, with increased times of exposure in the cabinet, the general devel...

Mössbauer spectroscopy study of iron corrosion underneath painting system

The effect of pigments on the development of corrosion products between the painting system and metal surface when exposed to marine environments has been discussed. The pigments studied were; Red Mud Zinc chromate, Zinc chromate, Red oxide Zinc Phosphate, Manganese Phosphate Barium chromate and Basic Lead Silico Chromate. Mossbauer Spectroscopy revealed that the upper rust layer in all the cases consisted ofγ-Fe203,γ-FeOOH andα-FeOOH. The lower rust layer immediately in contact with the metal surface consisted of an asymmetrical doublet due to γ-FeOOH.

The anodic oxidation of zirconium—II. Growth and morphology of anodic ZrO 2 films

Measurements of the rate of growth of anodic barrier films, the stresses in these films, and the relative film thicknesses after anodising in electrolytes which may contain fluoride ions have been interpreted as showing that the incorporation of F − ions into the oxide leads to a greater flux of zirconium ions which in turn may lead to tensile stresses in the oxide. These stresses can cause oxide fracture and the development of corrosion products. The incorporation of F − ions into the oxide depends upon the F − ion concentration in the electrolyte and the surface pH of the electrode. This latter is in turn dependent upon the bulk pH of the electrolyte and the applied current density. At high current densities the surface pH shifts to smaller values which leads to enhanced pick-up of F − ions; at low current densities higher surface pH's can prevent the pick-up of fluoride ions.