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Article
Publication date: 4 August 2020

Xiaochen Hu, Pei Zhang, Yong Zhou and Fuan Yan

The purpose of this paper is to reveal the mechanism of nitrite (NO2) for the surface passivation of carbon steels in acidic environments through investigating the…

Abstract

Purpose

The purpose of this paper is to reveal the mechanism of nitrite (NO2) for the surface passivation of carbon steels in acidic environments through investigating the influences of 0.01 mol/L NaNO2 addition on the corrosion and passivation behaviors of Q235 carbon steel in acidic phosphate buffer (APB) solutions (pH 2 to 6).

Design/methodology/approach

The electrochemical techniques including open circle potential evolution, potentiodynamic polarization, electrochemical impedance spectroscopy and cyclic voltammetry were applied.

Findings

In APB solutions without NO2, the Q235 steel presented the electrochemical behaviors of activation (A), activation-passivation-transpassivation and self-passivation-transpassivation at pH 2 to 4, pH 5 and pH 6, respectively; the corrosion rate decreased with the up of pH value, and the surface passivation occurred in the pH 5 and pH 6 solutions only: the anodic passivation at pH 5 and the spontaneous passivation at pH 6.

Originality/value

In APB solutions without NO2, the corrosion rate decreased with the up of pH value, and the surface passivation occurred in the pH 5 and pH 6 solutions only: the anodic passivation at pH 5 and the spontaneous passivation at pH 6. With the addition of 0.01 mol/L NaNO2, into APB solutions, the variation of corrosion rate showed the same rule, but the surface passivation occurred over the whole acidic pH range, including the anodic passivation at pH 2 to 4 and the spontaneous passivation at pH 5 to 6.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 17 April 2020

Chuanbo Zheng, Jiayan Huang and Gua Yi

This paper aims to study the effect of current density of hydrogen charging on the semiconductor properties and pitting initiation of 2205 duplex stainless steel (DSS…

Abstract

Purpose

This paper aims to study the effect of current density of hydrogen charging on the semiconductor properties and pitting initiation of 2205 duplex stainless steel (DSS) passivation film.

Design/methodology/approach

In this work, the 2205 DSS is pre-hydrogenated and passivated. Then, the passivation film is tested by electrochemical impedance method, Mott–Schottky curve method and dynamic potential scanning method. The influences of hydrogen on the properties of the passivation film and the corrosion behavior of the matrix were studied by analyzing the curves obtained in the electrochemical test. The surface of the passivation film after pre-hydrogenation and anodic polarization was observed by using the ultra-depth three-dimensional microscopy and the scanning electron microscope. The integrity, density and corrosion morphology of the passivation film were studied and discussed.

Findings

With the increase of the hydrogen current density, the growth of the passivation film is hindered, the concentrations of donor and acceptor in the film are increased, the conductivity of the passivation film increases. In the anodic polarization, the dimensional passive current density increases with the increase of the hydrogen current density, and the pitting potential is reversed, the more likely the sample is pitting. In general, hydrogen hinders the formation of the passive film on duplex stainless steel, which increases the concentration of point defects in the passive film. Finally, the passive film is easy to crack and pitting.

Originality/value

The performance of passive film is an important condition to influence the corrosion behavior of stainless steel. However, little research has been done on the effects of hydrogen on the electrochemistry and pitting sensitivity of 2205 DSS passivation films. The effect of hydrogen on semiconductor properties and pitting initiation of 2205 DSS passivation film is needed to be investigated.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 28 December 2018

Junzhe Liu, Jundi Geng, Hui Wang, Mingfang Ba and Zhiming He

This paper aims to study the influence of NaNO2 on the chemical composition of passivation film.

Abstract

Purpose

This paper aims to study the influence of NaNO2 on the chemical composition of passivation film.

Design/methodology/approach

X-ray photoelectron spectroscopy and X-ray diffraction were selected to determine the composition of passivation film of steel bars in mortar. The specimens were exposed to the chloride solution, carbonation environment and the coupling effects of chloride solution and carbonation. The chemical composition and micro structures at 0 and 5 nm from the outer surface of the passivation film of steel bars were analyzed.

Findings

Results showed that the nitrite inhibitor improved the forming rate of the passivation film and increased the mass ratio of Fe3O4 to FeOOH on the surface of steel bars. The component of Fe3O4 at 5 nm of the steel passivation film was more than that at 0 nm. Sodium ferrite in the pore solution was easily hydrolyzed and then FeOOH was formed. Therefore, due to the nitrite inhibitor, a “double layer structure” of the passivation film was formed to prevent steels bars from corrosion.

Originality/value

This is original work and may help the researchers further understand the mechanism of rust resistance by nitrite inhibitor.

Details

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

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Article
Publication date: 2 July 2018

Barbara Swatowska

The purpose of this study is to verify the possibility of applying alumina (Al2O3) as the passivation and antireflective coating in silicon solar cells.

Abstract

Purpose

The purpose of this study is to verify the possibility of applying alumina (Al2O3) as the passivation and antireflective coating in silicon solar cells.

Design/methodology/approach

Model of a studied structure contains the following layers: Al2O3/n+/n-type Si/p+/Al2O3. Optical parameters of the aluminium oxide films on silicon wafers were measured in the range of wavelengths from 250 to 1,400 nm with a spectrophotometer Perkin Elmer Lambda 900. The minority carrier lifetime at the start of the n-type Si base material and after each of the next technological process was analysed by a quasi-steady-state photoconductance technique. The electrical parameters of the solar cells fabricated with four different thickness of the Al2O3 layer were determined on the basis of the current-voltage (I-V) characteristics. The silicon solar cells of 25 cm2 area and 300 µm thickness were investigated.

Findings

The optimum thickness of alumina as passivation layer is 90 nm. However, considering also antireflective properties of the first layer of a photovoltaic cell, the best structure is silicon with alumina passivation layer of 30 nm thickness and with TiO2 antireflective coatings of 60 nm thickness. Such solution has allowed to produce the cells with the fill factor of 0.77 and open circuit voltage of 618 mV.

Originality/value

Measurements confirmed the possibility of applying the Al2O3 as a passivation and antireflective coating (obtained by atomic layer deposition method) for improving the efficiency of solar cells.

Details

Microelectronics International, vol. 35 no. 3
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 3 August 2020

Yijiang Chen, Pei Zhang, Yong Zhou and Fuan Yan

The purpose of this work is to reveal the mechanism of WO42 on surface passivation for Q235 carbon steel in tungstate solution.

Abstract

Purpose

The purpose of this work is to reveal the mechanism of WO42 on surface passivation for Q235 carbon steel in tungstate solution.

Design/methodology/approach

In Na2WO4 solutions with the different concentrations of WO42, the spontaneous passivation occurred on the surface of Q235 carbon steel when the concentration of WO42 was up to 0.13 mmol/L, which was attributed to the formations of the inner deposition film and the outer adsorption film on the Q235 surface under the action of WO42.

Findings

The inner deposition film presented a two-layer microstructure: the inside layer was composed of Fe2O3 mainly, and the outside layer comprised Fe(OH)2•nH2O, Fe(OH)3•nH2O, FeWO4 and Fe2(WO4)3.

Originality/value

Both FeWO4 and Fe2(WO4)3 repaired the defects in the outside layer of the inner deposition film; however, the outer adsorption film played a more important role in the surface passivation than the inner deposition film did.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 August 2016

Stanislawa Kluska and Piotr Panek

In this paper, we aim to investigate the influence of the hydrogenated silicon nitride layers deposited by a large area 13.56 MHz plasma-enhanced chemical vapour…

Abstract

Purpose

In this paper, we aim to investigate the influence of the hydrogenated silicon nitride layers deposited by a large area 13.56 MHz plasma-enhanced chemical vapour deposition system on the electrical activity of the surface and interfaces of the grains for solar cells fabricated on microcrystalline silicon and multicrystalline silicon.

Design/methodology/approach

The characterization of current-voltage parameters of 25 cm2 solar cells manufactured with different passivation and antireflective layers are presented. After spectral response measurements, external quantum efficiency was calculated, and the final results are shown graphically. The passivation effect concerning grain areas was evaluated more precisely by light-beam-induced current scan maps (LBIC).

Findings

The final impact of the type of passivation layer on surface and grain boundary photoconvertion in solar cells is determined.

Originality/value

The passivation effect concerning grain areas was evaluated more precisely by LBIC.

Details

Microelectronics International, vol. 33 no. 3
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 4 November 2013

Madeleine Du Toit and Josias Willem Van der Merwe

– This investigation aims to find the degree of passivation required to completely inhibit the stress corrosion cracking of carbon steel exposed to CO-CO2-H2O environments.

Abstract

Purpose

This investigation aims to find the degree of passivation required to completely inhibit the stress corrosion cracking of carbon steel exposed to CO-CO2-H2O environments.

Design/methodology/approach

A516 pressure vessel steel was exposed to distilled water with 25 per cent CO and 75 per cent CO2 at an overall pressure of 800 kPa with the introduction of potassium bichromate as an additional inhibitor. Slow strain-rate tests were performed to evaluate the steel for sensitivity to cracking. Electrochemical characteristics were investigated in parallel in order to determine the extent of passivation required with the addition of the inhibitor.

Findings

Slow strain-rate tests showed that between 100 and 1,000 ppm potassium bichromate was required to completely mitigate cracking with a significant reduction in passivation current densities.

Research limitations/implications

The chosen inhibitor is not ideal for practical applications as an inhibitor, but gave an indication of the passivation required.

Practical implications

The results showed that the added inhibitor might even cause increased sensitivity to cracking in this environment, with significant passivation required for resistance to cracking.

Originality/value

The degree of passivation required for complete resistance of carbon steel in 25 per cent CO-75 per cent CO2-H2O.

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 August 1998

M. Vishnudevan, G. Venkatachari, S. Muralidharan and N.S. Rengaswamy

The corrosion behaviour of Inconel 600 and 601 alloys has been evaluated by DC polarisation method in orthophosphoric acid solution of concentrations 0.5N to 15N. The…

Abstract

The corrosion behaviour of Inconel 600 and 601 alloys has been evaluated by DC polarisation method in orthophosphoric acid solution of concentrations 0.5N to 15N. The passivation range from + 200mV to + 800mV has been observed for 601 alloy. In the case of Inconel 600 a less passivation range in comparison with Inconel 601 is observed. In addition, the passivation current has been found to be higher than that of 601 alloy. Tafel polarisation study indicates that Inconel 601 alloy is more corrosion resistant than Inconel 600.

Details

Anti-Corrosion Methods and Materials, vol. 45 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 August 2004

C.Y. Huang

Flip chip technology involves the attachment of active side of the silicon chip onto printed circuit board or substrate. The interconnections are provided by solder bumps…

Abstract

Flip chip technology involves the attachment of active side of the silicon chip onto printed circuit board or substrate. The interconnections are provided by solder bumps, which are arranged in the area under the chip. Encapsulation helps reduce the impact of the thermal stress that results from the mismatch in the coefficient of thermal expansion between the silicon chip and the substrate. The adhesion of the encapsulant to the chip and the board coating are essential to the reliability of the package. This paper studies the adhesion characteristics of an encapsulant to a flip chip package. The quality of the encapsulation was inspected using a scanning acoustic microscope. The electrical continuity of the assemblies was tested during the liquid‐to‐liquid thermal shock testing. The various delamination mechanisms were then studied. Delamination was found predominantly at the interface between the passivation layer and the encapsulant material. Comparisons were made between samples assembled by different materials used, such as chip passivation layer, encapsulant materials, and fluxes. Finally, the best material combination was determined.

Details

Microelectronics International, vol. 21 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 December 2002

B. Jabeera, S.M.A. Shibli and T.S. Anirudhan

Zinc ions, produced by the electrolytic dissolution of zinc metal rods, exhibited excellent inhibition efficiency, especially in combination with the synergistic additions…

Abstract

Zinc ions, produced by the electrolytic dissolution of zinc metal rods, exhibited excellent inhibition efficiency, especially in combination with the synergistic additions of tungstate and nitrite ions. The optimum ratio of tungstate: nitrite: zinc was found to be 10:10:1 and the combination of tungstate: 100 ppm ‐ nitrite: 100 ppm ‐ zinc: 10 ppm (System A) gave the best results of all the systems studied. This system requires a much smaller concentration of tungstate and nitrite ions, as compared to the concentrations typically used and claimed to offer optimal inhibition efficiency. Long‐term open circuit potential measurements indicated that effective passivation occurred within 3 days of immersion. The passive layer thus formed on the metal surface retained its protective capability for several weeks, even after test coupons were transferred into a depleted inhibitor solution. The possible mechanism of the passivation is discussed.

Details

Anti-Corrosion Methods and Materials, vol. 49 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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