Anodizing Steel in KOH and NaOH Solutions

Burleigh, Thomas D.; Dotson, Thomas; Dotson, K. T.; Gabay, S. J.; Sloan, T. B.; Ferrell, S. G.

doi:10.1149/1.2767417

Cited by 33 publications

(32 citation statements)

References 15 publications

(20 reference statements)

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“…The oxide thickness values that were found in this study fall in the interval reported for first-order interference in steels, from light yellow (46 nm) to blue (72 nm) [1,2,13].…”

Section: Figure 4 Schematic Representation Of An Absorbing Layer In Asupporting

confidence: 65%

Colour evolution of the oxide layer formed on the Au-25Fe and Au-24.5Fe-0.5Co alloys

Restrepo-Arcila

Echavarría-Velásquez

Giraldo

et al. 2015

Rev. Fac. Ing. Antioquia

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ABSTRACT:The colour theory proposed by Heavens in 1991 has been applied to calculate the thickness of magnetite thin layers, Fe 3 O 4 , which were obtained by heat treatment at 250 °C in a gold alloy (Au-24.5Fe-0.5Co). The reflectance spectra obtained from the polished samples with different oxidation (and colour) degrees were used to calculate the real part of the refraction index and the (imaginary) extinction coefficients of both the metallic substrate (n 2 , k 2 ) and the magnetite layer (n 1 =2.42, k 1 ). The a+bλ+cλ 2 form was taken adjusting parameters between experimental and theoretical curves. The fitting of the data resulted in deviations between 2 and 10% for thicknesses in the range of 0 nm (only substrate) and 65 nm (dark blue colour). By means of a mathematic model and following the Heavens' theory, the thickness of each layer has been predicted with high precision, using the spectral reflectance. Consequently, we propose that by using this methodology, the values of the extinction coefficients of the oxide species can be easily obtained, and the thicknesses of the oxide layers can be predicted. The magnetite thickness values found in this study fall into the interval reported in the literature for first-order interference in steels, from light-yellow (~46 nm) to blue (~72 nm). RESUMEN:Se aplica la teoría del color propuesta por Heavens (1991) para el cálculo de los espesores de las películas delgadas de magnetita, Fe 3 O 4 , los cuales fueron obtenidos por tratamiento térmico a 250°C de una aleación de oro (Au-24.5Fe-0.5Co).Los espectros de reflectancia obtenidos de las muestras pulidas con diferentes grados de oxidación (y de color) fueron usados para calcular los índices de refracción (real) y de extinción (imaginario) del sustrato metálico (n 2 , k 2 ) y de la capa de magnetita (n 1 =2,42, k 1 ). La forma a+bλ+cλ 2 se tomó del ajuste de parámetros entre las curvas experimentales y teóricas. El ajuste de los datos resultan en desviaciones entre 2 y 10%, para los espesores en el rango de 0 nm (solo metal original) y 65 nm (color azul oscuro). Por medio de un modelo matemático siguiendo la teoría de Heavens, el espesor de cada capa ha sido predicho con alta precisión, utilizando las mediciones de reflectancia espectral. En consecuencia, proponemos que mediante el uso de esta metodología se pueden obtener fácilmente los valores de los coeficientes de extinción de las especies de óxido y, además, se pueden predecir los espesores de la capa de óxido. Los valores de espesores de la magnetita encontrados en la presente investigación están dentro del intervalo reportado en la literatura para la interferencia de primer orden en los aceros, desde el amarillo claro (~46 nm) hasta el azul (~72 nm).

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“…The oxide thickness values that were found in this study fall in the interval reported for first-order interference in steels, from light yellow (46 nm) to blue (72 nm) [1,2,13].…”

Section: Figure 4 Schematic Representation Of An Absorbing Layer In Asupporting

confidence: 65%

Colour evolution of the oxide layer formed on the Au-25Fe and Au-24.5Fe-0.5Co alloys

Restrepo-Arcila

Echavarría-Velásquez

Giraldo

et al. 2015

Rev. Fac. Ing. Antioquia

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“…A generation of soluble iron species such as ferrate ions is unlikely because the concentration of the alkali is not sufficient for this process [24].…”

Section: Resultsmentioning

confidence: 99%

Plasma electrolytic ceramic-like aluminum oxide coatings on iron

et al. 2009

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The process characteristics of plasma-assisted electrochemical treatment of iron in aluminate electrolyte consisted of aqueous 0.1 M NaAlO 2 ? 0.05 M NaOH have been studied. It has been shown that in the range of DC voltages from 260 to 340 V, it is possible to deposit dense ceramic-like coatings with the thickness increased from 0.3-0.5 lm after 1 min deposition time to 25-30 lm for 1 h of deposition. The coatings were examined by X-ray diffractometry, Fourier-transformed infrared, X-ray photoelectron spectroscopy, scanning electron microscopy, and an electrochemical potentiodynamic voltammetry. It is shown that in pre-spark conditions (100-200 V) and on the initial stages of micro-arc anodizing the forming films contain, along with amorphous aluminum oxide/hydroxide, a substantial amount of iron oxide/hydroxide. The coatings obtained by micro-arc anodizing at 260-360 V for 10-60 min represent amorphous aluminum oxide with inclusions of crystalline corundum phase. The films with a thickness of 4-15 lm deposited at the anodizing voltage of 320-360 V exhibited the uniformity and good corrosion protection properties after sealing with common agents.

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“…In order to prevent rust from damaging it, there are numerous methods and many of them involve a barrier layer between the steel and the environment. This barrier layer can be a sacrificial coating, such as zinc or aluminum, or an organic coating, such as paints, waxes or oils, or a barrier oxide [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…In order to improve the rate of the blackening process, the electrochemical process was employed [1,2,[27][28][29][30][31][32]. Bacsa et al [29] introduced the hydrothermal-electrochemical technique to synthesis barium titanate (BaTiO 3 ) at temperatures 80-200°C with titanium as an electrode and barium hydroxide (Ba(OH) 2 ) as an electrolyte solution.…”

Section: Introductionmentioning

confidence: 99%

“…2 lm in thickness. Next, Burleigh et al [1,2] demonstrated the possibility to electrochemically grow an adherent blue-black magnetite layer, a light brown oxide, or a semiadherent dichroic magnetite layer on many different types of steel in either KOH or NaOH solutions. The adherent, blue black magnetite layer that provide corrosion protection can be grown several micrometers thick on some carbon steels by selecting a narrow range of temperature, voltage and electrode spacing.…”

Section: Introductionmentioning

confidence: 99%

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Magnetite thin film on mild steel formed by hydrothermal electrolysis for corrosion prevention

Machmudah

Zulhijah

Diono

et al. 2015

Chemical Engineering Journal

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h i g h l i g h t sMagnetite was formed dominantly on the surface of mild steel with black color. The growth rate of magnetite film increased with increasing temperature and reaction time. The magnetite films formed on the mild steel surface could prevent or minimize the corrosion on its surface. a b s t r a c tMagnetite film was successfully prepared on the mild steel surface in alkaline environment by hydrothermal electrolysis treatment. The principle of hydrothermal electrolysis is applying current directly to electrolyte solution at hydrothermal conditions. The anodizing of mild steel was conducted at temperatures of 100-200°C and applied current densities of 0.1-0.4 A/cm 2 for 5-60 min reaction time with sodium hydroxide (NaOH) as an electrolyte solution (5-15%). Magnetite film on the mild steel surface was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and cyclic voltammetry. The patterns of XRD showed that magnetite was formed dominantly in the surface of mild steel with black color. Cyclic voltammetry analysis showed that the magnetite films produced on the mild steel surface could prevent or minimize the corrosion on its surface.

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Anodizing Steel in KOH and NaOH Solutions

Cited by 33 publications

References 15 publications

Colour evolution of the oxide layer formed on the Au-25Fe and Au-24.5Fe-0.5Co alloys

Colour evolution of the oxide layer formed on the Au-25Fe and Au-24.5Fe-0.5Co alloys

Plasma electrolytic ceramic-like aluminum oxide coatings on iron

Magnetite thin film on mild steel formed by hydrothermal electrolysis for corrosion prevention

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