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Article
Publication date: 11 June 2018

Somrerk Chandra-ambhorn, Sermsak Srihirun and Thamrongsin Siripongsakul

The purpose of this study is to investigate the aesthetic blackening coating formed by a hydrothermal process, focusing on the formation of magnetite and the oxide…

Abstract

Purpose

The purpose of this study is to investigate the aesthetic blackening coating formed by a hydrothermal process, focusing on the formation of magnetite and the oxide adhesion for improving the corrosion resistance of the steel.

Design/methodology/approach

The aesthetic black coating was applied on AISI 4140 steel using a hydrothermal process with a non-toxic solution consisted of ferrous sulphate hydrate (FeSO4·7H2O), sodium hydroxide (NaOH) and hydrazine hydrate (N2H4·H2O). Upon process parameters temperature and time, the morphology of the coatings and oxidation kinetics were investigated by using scanning electron microscopy and X-ray diffraction (XRD) analysis. Furthermore, the samples with coatings were subjected to the adhesion test using a tensile testing machine equipped with a charge-coupled device (CCD) camera.

Findings

From the formation parameters due to temperature and time for the conversion coatings, it was found that the oxidation kinetics had special characteristics which were in accordance with a linear rate law and Arrhenius relation. For the samples blackened, the XRD analysis results revealed that the magnetite was successfully formed on the surface of the steel. On the other hand, increasing the blackening temperature worsened the scale adhesion as observed by the lower strain provoking the first spallation and the higher sensitivity of the oxide to spall out with the imposed strain.

Originality/value

The effects of parameters of the formation of conversion coatings were investigated to understand the kinetics of the coatings. Furthermore, a tensile adhesion test using a CCD camera was applied to evaluate the adhesion between the native oxide formed by conversion coating.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 1 July 1966

C.W. Tuck, M. Odgers and K. Sachs

The work described in this paper is part of a current programme that has two objects: (1) to investigate further the reasons for the different scaling behaviour of steel…

Abstract

The work described in this paper is part of a current programme that has two objects: (1) to investigate further the reasons for the different scaling behaviour of steel in steam and carbon dioxide, although these gases have similar oxygen potentials; (2) to provide background information for an investigation into the effect of variations in re‐heating furnace atmospheres upon scaling and scale adhesion.

Details

Anti-Corrosion Methods and Materials, vol. 13 no. 7
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 1 April 1966

K. Sachs, C.W. Tuck and J. Barlow

TWO nickel‐bearing commercial steels were oxidised in the range 1100°–1250°C for up to 8 hr. in air and CO2. The increase in thickness of the scale and the inner layer…

Abstract

TWO nickel‐bearing commercial steels were oxidised in the range 1100°–1250°C for up to 8 hr. in air and CO2. The increase in thickness of the scale and the inner layer with embedded metal particles was followed in detail. A distinction is made between filaments which retain continuity with the base metal and discrete particles. The continuous filaments may be of practical importance in holding the scale to the metal in hot rolling, leading to surface defects on hot‐rolled products.

Details

Anti-Corrosion Methods and Materials, vol. 13 no. 4
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 1 January 1971

N.R. Chapman

DISCUSSION The chromium coating thicknesses used in this work were comparable to those used commercially, being between 70 and 170 micrometres approximately. Even after…

Abstract

DISCUSSION The chromium coating thicknesses used in this work were comparable to those used commercially, being between 70 and 170 micrometres approximately. Even after oxidation for the temperatures and times stated the chromium concentrations at the metal‐oxide interface were between 20% and 60%. These concentrations fell steadily to approximately 13% over the approximate depth stated above before reducing sharply to zero at what was the ferrite‐austenite transformation boundary during the coating process. This is contrary to the structure observed in aluminized stainless steels where a complex structure is produced due to the existence of intermetallic phases. Hence during all the oxidation experiments performed the chromium level of the surface offered for oxidation was never below 13% and complete oxidative breakdown therefore did not occur, excluding spalling effects. Many workers have shown that the oxidation rate of iron‐chromium alloys initially drops sharply with increasing chromium but eventually reaches a minimum of about 20% chromium and then rises for more chromium rich alloys. From the graph of oxidation rate in pure oxygen against chromium content given by Mortimer et al., from 13% chromium to 100% chromium the oxidation rate increases by approximately 6 × 10−9 g.cm−2 sec.−1 It is reasonable to assume that for a diffusion coating the oxidation behaviour will be markedly affected by the composition at its outer surface layer and much less by the composition gradient. If oxidation was continued for sufficiently long periods the latter could affect the general availability of chromium ions for the oxidation process. Over the first 5?m the average chromium levels were between 63% and 20% for the chromised and chrome‐aluminized respectively. From the figures given by Mortimer et al the oxidation rate of the 63% chromium coating would be expected to be 0.5 × 10−9 g.cm−2 sec−1 greater than the 20% chromium coating on the chrome‐aluminized specimens at 600°C, on the basis of the chromium content alone. The results obtained here vary in this manner, hence it is reasonable to conclude that the general oxidation behaviour of the coatings will be very similar to that of pure iron‐chromium alloys containing the same chromium content as in the outer few micrometres of the respective coatings. Even though the true surface area is greater with diffusion treated specimens their oxidation rates are lower that for the corresponding pure alloys.

Details

Anti-Corrosion Methods and Materials, vol. 18 no. 1
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 9 April 2021

Yanbo Zhu, Xiaohong Chen, Ping Liu, Shaoli Fu, Honglei Zhou and Jiayan Wu

This study aims to investigate the effect of changes in iron content in 70/30 copper–nickel alloy on the corrosion process.

Abstract

Purpose

This study aims to investigate the effect of changes in iron content in 70/30 copper–nickel alloy on the corrosion process.

Design/methodology/approach

70Copper–30Nickel-xFe-1Mn (x = 0.4,0.6,0.8,1.0 Wt.%) alloy were prepared by the high frequency induction melting furnace. The scanning electron microscope, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy were used to analyze the morphology and component of the corrosion product film.

Findings

The results show that the corrosion resistance of 70/30 copper–nickel alloy added with 1.0%Fe is the best, and the film is divided into inner dense Cu2O composite film and outer hydration loose layer; XRD showed that after adding 1.0% Fe, the content of Cu2(OH)3Cl in the corrosion product film was significantly reduced, while the content of Cu2O remained unchanged; XPS showed that nickel accumulates in the inner layer of corrosion product film; the stage growth mode of the film, the role of nickel in it and the enrichment mechanism of iron in the inner film were summarized and discussed.

Originality/value

The changes in the composition and structure of the corrosion product film caused by the iron content are revealed, and the mechanism of the difference in corrosion resistance is discussed.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 14 June 2013

Mieczysław Kaczorowski and Radosław Winiczenko

The results of a study of friction welding of ductile cast iron using stainless steel interlayer are presented. Based on the microstructure evolution at the region close…

Abstract

Purpose

The results of a study of friction welding of ductile cast iron using stainless steel interlayer are presented. Based on the microstructure evolution at the region close to the ductile cast iron‐stainless steel interface, the phenomena accompanying the process of joining were evaluated. Therefore, the purpose of this paper is to take a closer look into metallurgical phenomena accompanying the friction welding of ductile cast iron.

Design/methodology/approach

In this paper, ductile cast iron and austenitic‐stainless steel are welded using the friction welding method. The tensile strength of the joints was determined using a conventional tensile test machine. Moreover, the hardness across the interface ductile cast iron‐stainless steel interface was measured on a metallographic specimen. The microstructure of the joints was examined using light metallography as well as electron microscopy. In this case, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied. Energy Dispersive X‐ray analysis (EDS) was carried out across the section of friction welded ductile iron‐stainless steel interface.

Findings

On the basis of careful analysis of experimental data it was concluded that the process of friction welding was accompanied with diffusion of Cr, Ni and C atoms across the ductile cast iron‐stainless steel interface. This leads to an increase of carbon concentration in stainless steel where chromium carbides were formed, the size and distribution of which was dependent on the distance from the interface.

Originality/value

The main value of this paper is to contribute to the literature on friction welding of ductile cast iron.

Details

Industrial Lubrication and Tribology, vol. 65 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 11 December 2018

Somrerk Chandra-Ambhorn, Sompong Chueaprakha and Thamrongsin Siripongsakul

The dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were investigated on oxidation at 700°C with the effects of dissolved nitrogen in the welds. This paper aims to…

Abstract

Purpose

The dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were investigated on oxidation at 700°C with the effects of dissolved nitrogen in the welds. This paper aims to clarify the oxidation behaviors to expand the range of application for Fe-Cr-Mn stainless steel.

Design/methodology/approach

Dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were fabricated using gas tungsten arc welding to investigate the oxidation behavior of the welds at 700°C. Pure Ar and Ar-4%N2 shielding gases were used to evaluate the effects of nitrogen gas. The welds were introduced to the cyclic oxidation test. In each cycle, the furnace was heated up to 700°C, and the temperature was kept at 700°C for 8 h, then the mass gain because of oxidation was examined. The scales after oxidation test were investigated by using scanning electron microscopy with EDX and X-ray diffraction analysis.

Findings

Addition of 4 per cent nitrogen to Ar shielding gas reduced delta-ferrite content in the weld. Ar-4%N2 shielding gas resulted in dissolved nitrogen which helped increase the diffusivities of chromium or oxygen vacancies in the oxide to facilitate the chromia formation at the inner part near the steel substrate. This protective layer can help reduce the Fe outward diffusion, thus reducing mass gain because of iron oxide formation.

Originality/value

The oxidation behavior of dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were investigated at 700°C. The evaluation is beneficial for expanding the range of application of Fe-Cr-Mn stainless steel at high temperature.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 20 December 2021

Xiang Qiu, Kun Zhang, Qin Kang, Yicheng Fan, Hongyu San, Yiqing Chen and Heming Zhao

This paper aims to study the mechanism of hydrogen embrittlement in 12Cr2Mo1R(H) steel, which will help to provide valuable information for the subsequent hydrogen…

70

Abstract

Purpose

This paper aims to study the mechanism of hydrogen embrittlement in 12Cr2Mo1R(H) steel, which will help to provide valuable information for the subsequent hydrogen embrittlement research of this kind of steel, so as to optimize the processing technology and take more appropriate measures to prevent hydrogen damage.

Design/methodology/approach

The hydrogen diffusion coefficient of 12Cr2Mo1R(H) steel was measured by the hydrogen permeation technique of double electrolytic cells. Moreover, the influence of hydrogen traps in the material and experimental temperature on hydrogen diffusion behavior was discussed. The first-principles calculations based on density functional theory were used to study the occupancy of H atoms in the bcc-Fe cell, the diffusion path and the interaction with vacancy defects.

Findings

The results revealed that the logarithm of the hydrogen diffusion coefficient of the material has a linear relationship with the reciprocal of temperature and the activation energy of hydrogen atom diffusion in 12Cr2Mo1R(H) steel is 23.47 kJ/mol. H atoms stably exist in the nearly octahedral interstices in the crystal cell with vacancies. In addition, the solution of Cr/Mo alloy atom does not change the lowest energy path of H atom, but increases the diffusion activation energy of hydrogen atom, thus hindering the diffusion of hydrogen atom. Cr/Mo and vacancy have a synergistic effect on inhibiting the diffusion of H atoms in α-Fe.

Originality/value

This article combines experiments with first-principles calculations to explore the diffusion behavior of hydrogen in 12Cr2Mo1R(H) steel from the macroscopic and microscopic perspectives, which will help to establish a calculation model with complex defects in the future.

Details

Anti-Corrosion Methods and Materials, vol. 69 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 1 January 1978

The Equal Pay Act 1970 (which came into operation on 29 December 1975) provides for an “equality clause” to be written into all contracts of employment. S.1(2) (a) of the…

1090

Abstract

The Equal Pay Act 1970 (which came into operation on 29 December 1975) provides for an “equality clause” to be written into all contracts of employment. S.1(2) (a) of the 1970 Act (which has been amended by the Sex Discrimination Act 1975) provides:

Details

Managerial Law, vol. 21 no. 1
Type: Research Article
ISSN: 0309-0558

Article
Publication date: 1 February 1968

J.A. Von Fraunhofer and G.A. Pickup

In the study of a corrosion phenomenon, corrosion product analysis can only be regarded as a part, albeit essential, of the whole investigation. The content to which any…

Abstract

In the study of a corrosion phenomenon, corrosion product analysis can only be regarded as a part, albeit essential, of the whole investigation. The content to which any corrosion process, and its manifestations, is studied is governed by several factors, which include the information required, the motive behind the investigation (research or industrial), the relevance of laboratory tests with respect to service conditions and the cost of the work. The ad hoc solutions of a plant engineer are often satisfactory over an indefinite period but they can only rarely be regarded as the complete answer to a particular corrosion problem although they will permit the plant to carry on in operation. The corrosion engineer must be able to justify his proposed research or fundamental investigations into a corrosion process from a cost and time standpoint.

Details

Anti-Corrosion Methods and Materials, vol. 15 no. 2
Type: Research Article
ISSN: 0003-5599

1 – 10 of 447