Search results

1 – 2 of 2
To view the access options for this content please click here
Article
Publication date: 22 December 2020

Guanghui Yi, Dajiang Zheng and Guang-Ling Song

The purpose of this paper is to address the concern of some stainless steel users. To understand the effect of surface white spots on corrosion performance of stainless steel.

Abstract

Purpose

The purpose of this paper is to address the concern of some stainless steel users. To understand the effect of surface white spots on corrosion performance of stainless steel.

Design/methodology/approach

White spots appeared on some component surfaces made of 316 L stainless steel in some industrial applications. To address the concern about the pitting performance in the spot areas, the pitting corrosion potential and corrosion resistance were measured in the spot and non-spot areas by means of potentiodynamic polarization and electrochemical impedance spectroscopy and the two different surface characteristics were analytically compared by using optical microscopy, laser confocal microscopy, scanning electron microscopy, x-ray diffraction, energy dispersive spectroscopy and auger energy spectroscopy. The results indicated that the pitting performance of the 316 L stainless steel was not negatively influenced by the spots and the white spots simply resulted from the slightly different surface morphology in the spot areas.

Findings

The white spots are actually the slightly rougher surface areas with some carbon-containing species. They do not reduce the pitting resistance. Interestingly, the white spot areas even have slightly improved general corrosion resistance.

Research limitations/implications

Not all surface contamination or roughening can adversely affect the corrosion resistance of stainless steel.

Practical implications

Stainless steel components with such surface white spots are still qualified products in terms of corrosion performance.

Originality/value

The surface spot of stainless steel was systematically investigated for the first time for its effect on corrosion resistance and the conclusion was new to the common knowledge.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

To view the access options for this content please click here
Article
Publication date: 25 July 2019

Chi Zhang, Dajiang Zheng, Guang-Ling Song, Yang Guo, Ming Liu and Hamid Kia

This study aims to propose a simple experimental method to distinguish the galvanic corrosion, crevice corrosion and self-corrosion in metal/carbon fiber reinforced…

Abstract

Purpose

This study aims to propose a simple experimental method to distinguish the galvanic corrosion, crevice corrosion and self-corrosion in metal/carbon fiber reinforced polymer (CFRP) joints.

Design/methodology/approach

The corrosion behaviors of four different galvanic couples, whose anodes were Zn-coated DP590 steel and Al 6022, and cathodes were two kinds of CFRP, were investigated in immersion and GMW14872 cyclic conditions.

Findings

The results showed that the galvanic corrosion caused by direct contact between CFRP and metals was more serious than that caused by the jointing bolts. The corrosion damage caused by crevice corrosion was severer than that caused by galvanic corrosion. Self-corrosion was also significant, particularly under the cyclic salt spray condition.

Practical implications

Cyclic salt spray test may more reliably simulate the galvanic corrosion of a joint in industrial service environments, and real corrosion damage may be underestimated by a galvanic current measurement.

Originality/value

A deeper understanding of different corrosion mechanisms involved in CFRP/metal joints under different service conditions in industry has been given.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

1 – 2 of 2