Self-passivation of Fe-Cr-PGM alloys in reducing acids studied by electrochemical and electron spectroscopic techniques

Tjong, S.C.

doi:10.1016/0169-4332(90)90040-7

Cited by 26 publications

(3 citation statements)

References 26 publications

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“…Even when ruthenium has been added to the bulk of an alloy at low concentrations, it has been found that corrosion rates of stainless steels can be reduced (Olubambi et al, 2009). When noble metals such as ruthenium are added to an alloy the corrosion potential of the alloy becomes more noble and is moved into the passive region through cathodic modification because of the higher exchange current density and low over voltage for the hydrogen evolution reaction (Tjong, 1990).…”

Section: Introductionmentioning

confidence: 99%

“…Various explanations have been given for the slow shifting of the corrosion potential of stainless steel by the addition of ruthenium. Tjong (1990) credited it to the presence of ruthenium in the steel which allows ruthenium to be taken up in the surface scale. Potgieter et al (1990) also showed that cathodic modification can increase corrosion resistance of materials in non-oxidizing acids, by increasing the potential to a value that is in the passive potential range.…”

Section: Introductionmentioning

confidence: 99%

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The corrosion resistance of low concentration ruthenium laser alloyed 304L stainless steel exposed to sulphuric acid at 25°C

Merwe

Nelwalani

2018

ACMM

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Purpose This paper aims to study the effect of small ruthenium additions through laser surface alloying of 304L stainless steel on the corrosion resistance when exposed to a 1 M sulphuric acid solution at 25°C. Design/methodology/approach In this study, the characteristics of laser-alloyed surface layers enriched with low concentrations of ruthenium, less than 0.3 Wt.%, were evaluated. Samples were manufactured by performing laser surface alloying on a 304L stainless steel and using a 304 stainless steel powder enriched with ruthenium. The welded surfaces were cross-sectioned and the microstructure and chemical composition were analysed; in addition, the depth of penetration was determined. The corrosion characteristics of these surface welds were investigated through electrochemical analysis such as open circuit potential measurements and potentiodynamic scans. Findings It was found that with the addition of ruthenium levels of more than 0.2 Wt.%, the corrosion characteristics when exposed to 1 M sulphuric acid improved in the enriched welded zone. Research limitations/implications This study investigated the improvement of the surface layer of the 304L stainless steel because of the cost involved when ruthenium is alloyed in the bulk and showed that an improved corrosion resistance can be achieved in sulphuric acid at room temperature. Practical implications The hardness of the laser alloying was not significantly affected by the ruthenium, but more by the laser parameters. Originality/value This paper considers the improvement of 304L stainless steel through laser alloying with ruthenium.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The corrosion resistance of low concentration ruthenium laser alloyed 304L stainless steel exposed to sulphuric acid at 25°C

Merwe

Nelwalani

2018

ACMM

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“…Tjong et al 1 showed with only the addition of up to 0.2 wt-% Pd and Ru that corrosion resistance improved in reducing acids. Stainless steels alloyed with Ru have been gaining focus in recent years by, for example, Potgieter and Brookes, 2 Banda and Van der Merwe, 3 Govender et al , 4 Myburg et al , 5 Tjong 6 and Sherif et al , 7 all clearly stated that both the general and pitting corrosion resistance is significantly increased by alloying with small amounts of Platinum Group Metals (PGMs). They found corrosion resistance is dependent on PGM concentration and the environment.…”

Section: Introductionmentioning

confidence: 99%

Corrosion resistance of laser cladded 304L stainless steel enriched with Ru in hydrochloric acid

Merwe

Tharandt

2016

Corrosion Engineering, Science and Technology

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The corrosion behaviour of laser surface cladding made from 304L stainless steel alloyed with varying concentrations of ruthenium in 1M HCl at 25°C was evaluated, fresh and after 12 hours, by electrochemical tests including open circuit potential and potentiodynamic polarisation scans. The ruthenium concentration in the 800 µm cladded layer varied from 0.82 wt-% to 4.67 wt-% ruthenium. The ruthenium doped samples were compared against a 304L stainless steel laser surface cladding with no ruthenium, 304L stainless steel samples with no laser cladding, 316L stainless steel, SAF2205 duplex stainless steel and Hastelloy C276®. Initial passivation was not observed in the 1M HCl but after 12 hours the addition of ruthenium led to reduced corrosion rates and improved passivation characteristics compared to the surface cladding without ruthenium. An optimum ruthenium range was observed between 3 wt-% and 5 wt-%. It was shown that at this optimum concentration, the ruthenium containing stainless steel clad on 304L stainless steel can compete commercially with the SAF2205 and Hastelloy C276® as long as the clad is 200 µm or less.

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The nature of the passive film on cathodically modified stainless steels

1993

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Self-passivation of Fe-Cr-PGM alloys in reducing acids studied by electrochemical and electron spectroscopic techniques

Cited by 26 publications

References 26 publications

The corrosion resistance of low concentration ruthenium laser alloyed 304L stainless steel exposed to sulphuric acid at 25°C

The corrosion resistance of low concentration ruthenium laser alloyed 304L stainless steel exposed to sulphuric acid at 25°C

Corrosion resistance of laser cladded 304L stainless steel enriched with Ru in hydrochloric acid

The nature of the passive film on cathodically modified stainless steels

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