Corrosion Testing Of Materials Research Articles

Evaluation of Corrosion Resistance and Surface Film Analysis after Corrosion Testing of Materials Coated by Chemical Densified Coating Method under Boiling Sulfuric Acid Environment

For the purpose of developing metallic materials with excellent corrosion resistance under boiling sulfuric acid environment, the coated materials were evaluated for their corrosion resistance and the differences in surface morphology were investigated. As a result, the corrosion resistance of SUS304 coated and sintered eight times by chemical densified coating method (S-ZAC) was maintained at the point after 12h corrosion test, but the corrosion rate rapidly increased after 100h corrosion test. The cross-sectional microstructural analysis of the specimens showed that only a small amount of SiO2 remained on the surface, while Cr2O3 completely disappeared. The mechanism of film delamination in S-ZAC is assumed to be due to the thermal expansion caused by heating, which resulted in curvature of the thick film and cracks at the Cr2O3 and SiO2 interfaces. On the other hand, SUS304 coated with higher density of Cr2O3 by repeating the coating and sintering eleven times (MS-ZAC) showed excellent corrosion resistance as well as SiC even after 100h corrosion test. The results of cross-sectional microstructural analysis showed that MS-ZAC had higher Cr2O3 concentration, finer SiO2 grain size, and fewer porosity than S-ZAC. In particular, the mechanism of film maintenance in MS-ZAC is assumed to be the formation of a stacked structure in Cr2O3 particle layer, in addition to the thinning of the entire film.

The Grimsel Test Site – more than 35 years of underground research

Abstract. Nagra and its international partners have been conducting underground research projects at the Grimsel Test Site (GTS, https://www.grimsel.com, last access: 8 November 2021) for more than 35 years. The results have been incorporated directly into modelling, safety and engineering feasibility studies necessary for the siting and construction of deep geological repositories. Various types of experiments are carried out at the GTS, each involving field testing, laboratory studies, design and modelling tasks, thus integrating all scientific aspects. Projects are typically planned over a 5 year period with the option to extend depending on the latest findings from the experiment. In the current 5 year programme (2019–2023) new phases of running in situ experiments using radionuclides were started and include the Long-Term Diffusion experiment (LTD) and the Colloid Formation and Migration project (CFM). A completely new experiment studying the migration of C-14 and I-129 in aged cement (CIM) was also initiated. Other experiments focusing mostly on engineered barrier materials were continued such as the Material Corrosion Test (MaCoTe), which is studying anaerobic corrosion of candidate canister materials in bentonite (Fig. 1). Also, a 1:1 scale experiment studying the high-temperature (>175∘C) effects on bentonite materials (HotBENT project) was started last year. In this paper we provide an overview of the CIM, LTD and MaCoTe projects, including key findings so far. In addition to research, the GTS, as part of the Grimsel Training Centre (GTC), is also used as an education platform for knowledge transfer to the next generation of scientists and engineers in the area of radioactive waste disposal and geosciences.

Design of specimen holders for flow accelerated corrosion experiments in molten lead with numerical evaluation of pressure losses

A material corrosion test loop (“Lobo Lead Loop”) has been established at the University of New Mexico to investigate the compatibility of structural materials with flowing molten lead. The project aims to prequalify materials for Versatile Test Reactor (VTR) testing and support the development of computational models of flow accelerated corrosion in molten lead. The Lobo Lead Loop is designed to operate at high temperatures up to 700 °C and high mean flow velocities reaching 3 m/s within the specimen holder channels. Numerical simulations are utilized to design loop components with performance that allows for achieving the operation targets. Specimen holders are designed for (a) multi-material testing at 3 m/sec, (b) multi-velocity testing, (c) shear stress testing, and (d) high temperature (≥600 °C) testing at low mass flow rates. The computational fluid dynamics models used are shown to produce results in agreement with experimental data for flow in pipes. The models are then used in parametric analyses to identify parameters of importance to specimen holder design and computation of pressure losses for flows along smooth and rough specimen walls. Specimen holder designs for the purposes outlined are presented along with performance curves. The maximum achievable flow rate is estimated based on the intersection of the pump performance curve with the system curve.

The series of measures for improvement of safety in oil and gas facilities producing, processing and transporting materials containing hydrogen sulfide Part 1. Corrosion-mechanical attack of hydrogen sulfide-containing media on steel equipment. The choice of construction steels and noncorrosive alloys for the oil and gas equipment

The necessity of the complex approach is defined for increase of reliability of the oil and gas equipment operated under pressure of hydrogen sulfide-containing medium, including: - control at the stages of design, manufacturing, commissioning, operation, repair and reconstruction; - organization of corrosion service; - rational choice of materials for equipment manufacturing and its repair; - use of different methods to protect equipment against corrosion: - diagnostics of equipment and evaluation of corrosion protection efficiency; - conducting corrosion tests of materials and corrosion control. The trend of increasing corrosive activity of the products of a number of hydrogen sulfide-bearing oil and gas fields is described. This is associated with their watering and contamination by sulfate-reducing bacteria. All types of corrosion-mechanical damage of steels in accordance with GOST R 53679-2009 (ISO 15156-1:2001) are considered. Comments are given on each of these types of damage and the types of steels that are prone to these defects are shown. The recommendations of GOST R 53679-2009 (ISO 15156-1:2001) are given for the selection of steel equipment operated under pressure of hydrogen sulfide-containing media depending on the type of their corrosionmechanical failure, with comments. Requirements for the use of steels modified with rare-earth metals (REM) and alkaline-earth elements (ALE) intended for operation in hydrogen sulfide-containing media are given.

Corrosion testing of materials in simulated superheated geothermal environment

This paper reports the results of corrosion study for carbon steel, austenitic stainless steel, as well as titanium and nickel-based alloys which were tested in a simulated superheated geothermal environment (SSGE) in flow-through reactors to investigate the corrosion behaviour to aid in the future material selection for high temperature deep geothermal application. The testing fluid was superheated steam (T = 350 °C and P = 10 bars gauge) containing H2S, CO2 and HCl with condensate of pH = 3. The corrosion rate for all samples was negligible but carbon steel was prone to localized damage under a magnetite film with a sulphur rich sublayer.

Development of the Composition of a Magnesium Alloy for the Fabrication of Temporal Sealing Facilities Used in the Petroleum Industry

The composition is developed and heat-treatment mode is determined for obtaining an intensely dissolving magnesium alloy for use as ball plugs in conditions of oil-well preparation, i.e., to seal various well sections with the subsequent and almost complete fracture of these balls in a short time (up to 11 h). It is revealed that the cause of a high dissolution rate of the Mg alloy, whose composition is close to high-strength ML6 alloy, is the increased nickel content in it (up to 0.19%). The compounds of this element are located along the grain boundaries, which leads to intense intercrystallite corrosion of the alloy in a medium containing chlorine ions. It is shown that an effective method for controlling the dissolution rate of the Mg alloy is the synthesis of coatings of various thicknesses on its surface by the plasma electrolytic treatment (PEO) in an aqueous solution containing 110 g/L of technical water glass. This method makes it possible to deposit coatings from 10 to 41 μm in thickness on the experimental magnesium alloy with an increased nickel concentration (~0.19%) in a short time period (from 10 to 20 min) with a low specified AC current density (4 A/dm2), which is the galvanostatic mode of PEO processes. The corrosion tests are performed in a 3% aqueous KCl solution at 93 ± 2°C, and PEO coatings are formed on the magnesium alloy using a capacitive setup. The conditions of the corrosion tests of materials used as ball plugs in sealing facilities of oil wells are similar to those presented by foreign researchers.

Simulation of the influence of test factors on the corrosion of metal materials tested for the aggressive influence of components of the industrial atmosphere in a salt spray chamber

Simulation of the influence exercised by the main test factors (humidity, temperature, and aggressive components of the atmosphere) on the corrosion of metal materials was performed with the purpose to develop methods for corrosion testing of materials, junctions, and products in order to estimate the performance level of devices under all climatic operating conditions. Theoretical values of the acceleration coefficients were obtained for each test factor. Values of the test parameters were calculated, namely, concentrations of aggressive substances in a test chamber. Taking into account the earlier work on simulation of the influence of aggressive components in the industrial atmosphere on metal materials in a salt spray chamber, the concentrations of test solutions were calculated.

The design and utilization of a high-temperature helium loop and other facilities for the study of advanced gas-cooled reactors in the Czech Republic

This paper focuses on the research infrastructure of advanced gas cooled reactors in the Czech Republic, particularly on the high-temperature helium loop HTHL, which is a unique facility of its kind. HTHL is intended mainly for testing structural materials. It also can be used to research technologies relating to helium coolant. The maximum temperature and pressure that can be used within the specimen testing space are 900 °C and 7 MPa, respectively, and the maximum gas flow rate in the main loop is 38 kg/hr. Originally, the equipment was envisaged as a device for corrosion tests of materials in the reactor LVR-15 but, according to current plans, a different equipment will be built for this purpose within the frame of the SUSEN project. At the same time, an additional helium loop (S-Allegro) will be built to test selected components of advanced gas-cooled reactors.

Effects of local radiolysis and geometric parameters on intergranular attack caused by crevice corrosion

Effects of γ-ray irradiation upon crevice corrosion (CC) of type 316L stainless steel (316L SS) as an initiation site of stress corrosion cracking in a boiling water reactor environment have been studied using a material corrosion test loop which could be irradiated with a 60Co γ-ray source during testing. The CC tests were conducted using crevice specimens with various sizes of crevice gaps. Many of the examined specimen surfaces exhibited a selective grain boundary dissolution; that is, intergranular attack (IGA) as a result of the CC when the crevice gap size was lower than a certain value. The IGA initiation time was shortened by the γ-ray irradiation. The IGA occurred mostly near the crevice mouth at a distance of less than 2 mm from the mouth edge. When γ-ray exposure had occurred, it was found that the number of IGA sites deeper in the crevice increased compared with the IGA site distribution under the no-irradiation condition. Since the electrochemical corrosion potential inside crevice specimens must be low under the conditions for which IGA could occur, it was assumed that γ-ray irradiation accelerated the corrosion rate of 316L SS by decreasing the Fe2+ surface activity inside the crevice or increasing the cathodic current of radiolytic oxidants on the crevice surface. It was concluded that γ-ray irradiation affects the IGA occurrence not only temporally but also spatially.

Design and Construction of an Innovative Device for Corrosion Testing of Materials in Different Environments

Corrosion is the deterioration of a substance (usually a metal) or its properties because of the reaction with its environment. There are many forms of corrosion, some of which are encountered in everyday life. Direct losses due to corrosion are more than $276 billion dollars annually = 3.1% of Gross Domestic Product only in the United States. If we consider the rest of the world this figure would be many times higher. However, corrosion and its control besides of its importance, is often a neglected element in the practice of engineering. This work presents the design of an innovative low cost device to carry out corrosion testing of materials in different environments. High costs that result from the fabrication of special probes or devices for testing, make it an interesting challenge for the engineer or designer. This original and innovative device has been designed accordingly to both the laboratory equipment which will do the characterization and assessment of the corrosion testing, as well as the “Loop reactor” where testing will be carried out in different environments.

SUPERCRITICAL WATER LOOP DESIGN FOR CORROSION AND WATER CHEMISTRY TESTS UNDER IRRADIATION

An experimental loop operating with water at supercritical conditions(25MPa, <TEX>$600^{\circ}C$</TEX> in the test section) is designed for operation in the research reactor LVR-15 in UJV Rez, Czech Republic. The loop should serve as an experimental facility for corrosion tests of materials for in-core as well as out-of-core structures, for testing and optimization of suitable water chemistry for a future HPLWR and for studies of radiolysis of water at supercritical conditions, which remains the domain where very few experimental data are available. At present, final necessary calculations(thermalhydraulic, neutronic, strength) are being performed on the irradiation channel, which is the most challenging part of the loop. The concept of the primary and auxiliary circuits has been completed. The design of the loop shall be finished in the course of the year 2007 to start the construction, out-of-pile testing to verify proper functioning of all systems and as such to be ready for in-pile tests by the end of the HPLWR Phase 2 European project by the end of 2009.

Current status of JAERI spallation target material program

In the joint project of spallation neutron source between JAERI and KEK, material technology has been developed for the mercury target in the neutron source facility, the lead–bismuth target in the transmutation test facility, superconducting accelerator, post-irradiation examination and the ion beam test. Design of target system is progressing for the mercury spallation target: a pressure test of moderator, an impacting test in mercury and a corrosion test have been carried out. For nuclear transmutation with ADS an engineering facility is proposed. A material corrosion test loop is built-up and SS316 and F82H steels are to be tested in a flowing Pb–Bi. Fracture toughness of superconducting cavity material was found to be considerably large at 4 K. Irradiated samples at SINQ are to be transported to JAERI Hot Laboratory. For simulating radiation damage small disk specimens were irradiated in single, dual and triple ion beam modes.

Accelerated corrosion tests for aerospace materials: current limitations and future trends

Examines accelerated methods for the corrosion testing of materials, coatings and surface treatments used in the aerospace and defence industries. The drawbacks with some current accelerated corrosion tests are examined, particularly the problems experienced with neutral salt spray tests. Specific examples are given which identify the acute discrepancy between salt spray and marine exposure in the corrosion testing of metallic coatings on steels. Examines some recent advances in corrosion testing of aerospace materials, pre‐treatments and organic coatings, and outlines some preliminary research conducted at DERA Farnborough in developing more accurate test methods.

The effect of specimen handling on the cyclic oxidation behaviour of Ti-48Al-2Cr

The importance is indicated of specimen handling during mass change measurements for cyclic oxidation testing. Four different microstructures of Ti-48 Al-2 Cr were used, i.e. near gamma, duplex, nearly lamellar and fully lamellar. Experiments were performed at 700 °C in air. Two different procedures for intermediate mass change measurements were employed. In the first procedure the specimens were mechanically touched with a pair of tweezers. In the second one, the specimens were only indirectly handled for weighing. These different ways of testing resulted in different results. It is concluded that care should be taken of these and other test conditions employed for cyclic corrosion testing of materials. Recommendations related to specimen handling for a Code of Practice are made.

General guidelines for corrosion testing of materials for marine applications: Literature review on sea water as test environment

This literature review is intended to give some general guidelines on corrosion testing of metals and alloys for marine applications, in particular with regard to the choice of the test environment. The general chemical properties of sea water are discussed and compared with those of coastal and/or polluted sea water, stored and recirculated sea water, and synthetic solutions which are sometimes used to simulate sea water. After discussing the factors that can affect the corrosion mechanism, the results of test methods are reviewed, highlighting the differences obtained in the various test environments. A short review of the main alloys used in marine applications is given, followed by a discussion of the factors that can lead to differences between results obtained when testing in natural sea water and in simulated test solutions.

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Long-term corrosion tests of materials for thermal decomposition of sulphuric acid

The corrosion resistance of tubes of Incoloy 800 and AISI 310 SS has been studied in a mixture of air and H 2SO 4 vapours at 1 bar pressure. The duration of the test was one year (8500 h). The temperatures of the tubes ranged from 400 to 700°C for SS AISI 310 and from 400 to 900°C for Incoloy 800. The extent of the attack was determined by measuring the scale thickness and the penetration depth on cross-sections of samples taken from several zones of the tubes. X-ray diffraction and S.E.M. X-ray microanalysis techniques were used.

Simulated Boiling Water Reactor and Superheat Reactor Corrosion Facility

A versatile boiling water and superheated steam facility has been developed for out-of-pile corrosion testing of materials that are being used and considered for application in boiling water reactor (BWR) and superheat reactor (SHR) systems. The following capabilities have been achieved: 1. Simulation of the various environments (other than irradiation) that would contact materials in a Dresden type BWR and an SHR utilizing steam generated therefrom. Test space is available at 1000 psi in saturated steam, steam-water mixture and saturated water at 546°F and in superheated steam at 1050°F.2. Dynamic fuel-cladding material tests operated with a heat flux of 250,000 Btu/hr-ft2 for testing tubular type cladding under representative BWR heat transfer conditions.3. Dynamic fuel-cladding-material tests operated with a heat flux of 170,000 Btu/hr-ft2 for testing tubular cladding under representative SHR heat-transfer conditions.4. Control of oxygen and hydrogen content in the steam and water to simulate the gas conditions from radiolytic water decomposition found in a BWR.5. Attainment of metal temperatures of 1300°F while superheating steam to 1050°F.