Metallographic etching reagents. III: For alloy steels

Groesbeck, E.C.

doi:10.6028/nbsscipaper.206

Cited by 3 publications

(4 citation statements)

References 10 publications

(16 reference statements)

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“…As the film formed on the deleterious phases in DSSs is composed by oxides of its forming components (chromium and molybdenum), the application of anodic potential in hydroxide solution generates the selective dissolution of these oxides, thus ensuring the selectivity of the method. 14,16 In a similar way, it is reported in the literature the use of microcells for the study of localized corrosion in metals and their alloys, the reduction of the area of analysis allows the comparison between microstructural characteristics and local electrochemical processes that could hardly be obtained in the study of global corrosion. 17,18,19 In addition, there is a gain in the quality of the signal obtained from the possibility of high rates of mass transport from the working electrode, reduction of capacitive currents and reduction of Ôhmic drop 20 .…”

Section: Introductionmentioning

confidence: 78%

“…These voltammograms presented peaks at approximately 0.07 and 0.15 V, wherein the peak at 0.07 presented higher current density. However, the current peak at 0.045 was not observed, a temporary phenomenon indicating its relation with some metastable phase such as the chi phase, which is a metastable phase of DSSs 16 as well as the appearance of the third peak at 0.15 V should be related to sigma phase precipitation.…”

Section: Linear Sweep Voltammetry In Potassium Hydroxide Solutionmentioning

confidence: 92%

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A New methodology of Nondestructive Testing for Quantitative Evaluation of Sigma Phase in Duplex Stainless Steels

2019

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Duplex Stainless Steels (DSSs) are widely used in the oil and gas industry. When the steel is subjected to a thermal gradient, as in welding may occur precipitation of intermetallic phases. Among these phases, there is the sigma phase, which even in small quantities reduces drastically the mechanical and corrosion resistance properties. According to some studies in the literature, the limit amount of sigma phase present in steel in welded joints must be in a maximum volume fraction of 2,5%. In search to improve the detection sensitivity of the sigma phase, this paper presents results obtained by Linear Sweep Voltammetry (LSV) in Duplex Stainless Steel UNS S31803 as a Nondestructive Testing (NDT) model. The innovation in the application of this test is to use a microcell-based system that allows a reduced area of analysis obtaining density of currents in the order of microamperes and in the use of selective electrolytes to the elements of the oxides present in the intermetallic phases. With the use of these systems and through the optimization of control parameters it was possible to detect very low amounts of deleterious phases such as the sigma and chi phases.

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Section: Introductionmentioning

confidence: 78%

Section: Linear Sweep Voltammetry In Potassium Hydroxide Solutionmentioning

confidence: 92%

A New methodology of Nondestructive Testing for Quantitative Evaluation of Sigma Phase in Duplex Stainless Steels

2019

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“…The etching effect produced by the Murakami's reagent originates from radical nascent oxygen [O] generated in the reaction occurring between potassium ferricyanide and alkali in close conjunction with metal carbides surface that has an attraction to oxygen 47 . When the surface is attacked by potassium ferricyanide K 3 [Fe(CN) 6 ] and KOH, the Ti 3 C 2 slabs withdraw the nascent oxygen from KOH on the slab surface, and the potassium left combines with potassium ferri cyanide K 3 [Fe(CN) 6 ] to form potassium ferrocyanide K 4 [Fe(CN) 6 ] (ref.…”

Section: Articlementioning

confidence: 99%

“…When the surface is attacked by potassium ferricyanide K 3 [Fe(CN) 6 ] and KOH, the Ti 3 C 2 slabs withdraw the nascent oxygen from KOH on the slab surface, and the potassium left combines with potassium ferri cyanide K 3 [Fe(CN) 6 ] to form potassium ferrocyanide K 4 [Fe(CN) 6 ] (ref. 47), according to the reaction:…”

Section: Articlementioning

confidence: 99%

Synthesis of goldene comprising single-atom layer gold

Kashiwaya,

Shi,

et al. 2024

Nat. Synth

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The synthesis of monolayer gold has so far been limited to free-standing several-atoms-thick layers, or monolayers confined on or inside templates. Here we report the exfoliation of single-atom-thick gold achieved through wet-chemically etching away Ti3C2 from nanolaminated Ti3AuC2, initially formed by substituting Si in Ti3SiC2 with Au. Ti3SiC2 is a renown MAX phase, where M is a transition metal, A is a group A element, and X is C or N. Our developed synthetic route is by a facile, scalable and hydrofluoric acid-free method. The two-dimensional layers are termed goldene. Goldene layers with roughly 9% lattice contraction compared to bulk gold are observed by electron microscopy. While ab initio molecular dynamics simulations show that two-dimensional goldene is inherently stable, experiments show some curling and agglomeration, which can be mitigated by surfactants. X-ray photoelectron spectroscopy reveals an Au 4f binding energy increase of 0.88 eV. Prospects for preparing goldene from other non-van der Waals Au-intercalated phases, including developing etching schemes, are presented.

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Color Metallography

Voort

2004

Metallography and Microstructures

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This article is a compilation of color etchants that have been developed for a limited number of metals and alloys. It describes the optical methods for producing color, such as polarized light and differential interference contrast, with illustrations. The article discusses film formation and interference techniques such as anodizing, chemical etching, and tint etching. It provides a description of reagents that deposit sulfide films and molybdate films. The article concludes with a discussion on the thermal and vapor deposition methods to produce color.

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Metallographic etching reagents. III: For alloy steels

Abstract: A quite complete, though brief, review of the literature on equilibrium dia-

Cited by 3 publications

References 10 publications

A New methodology of Nondestructive Testing for Quantitative Evaluation of Sigma Phase in Duplex Stainless Steels

A New methodology of Nondestructive Testing for Quantitative Evaluation of Sigma Phase in Duplex Stainless Steels

Synthesis of goldene comprising single-atom layer gold

Color Metallography

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