Depth profile analysis of copper coating on steel using laser ablation inductively coupled plasma mass spectrometry

Abstract

A commercial highly focused (Gaussian) nanosecond UV (266 nm) Nd:YAG laser ablation system coupled to an inductively coupled plasma quadrupole mass spectrometer was examined as a tool for depth profile analysis of copper coating on steel. The studied samples were Standard Reference Materials 1361b and 1362b from NIST, which consist of a set of eight coupons of an AISI 1010 cold rolled sheet steel substrate with a uniform coating of copper (certified copper coating thickness: 5.9, 12.3, 25.3, 40.6, 52.0, 77, 130, and 199 mm). Depth resolution was determined from the normalized depth profiles as a function of irradiance, which was varied by changing the laser pulse energy and the focusing conditions, as well as coating thickness. At lower irradiances, depth resolution values were higher for irradiances obtained by changing the laser pulse energy, whereas at higher irradiances this parameter was higher for irradiances obtained by changing the focusing conditions. At moderate irradiance levels, the results obtained were quite similar, and, in addition, the best depth resolution was attained in this irradiance range, which was obtained by using a moderate laser energy (about 2 mJ per pulse) and by focusing the laser beam below the sample surface (approximately 2000 mm). Depth resolution increased linearly with coating thickness. For the eight studied samples the ablation rate was approximately 1 mm per pulse and the depth resolution values were between 0.8 mm for the thinnest coating and 26 mm for the thickest one.

Resolución espacial en la ablación láser acoplada a la espectrometría de masas con fuente de plasma de acoplamiento inductivo.

“…Los parámetros que intervienen en la determinación de ∆z aparecen ilustrados en un trabajo previo de Coedo et al [20] .…”

“…Kanicky et al [19] , utilizando un láser excimer de ArF* (193 nm), han demostrado la dependencia de la resolución en profundidad con la relación diámetro/profundidad del cráter, para aceros recubiertos con capas de ZrN y TiN, obteniendo un valor óptimo de resolución en profundidad de 0,6 µm, para cráteres de 20 µm de diámetro. Coedo et al [20] han evaluado la resolución en profundidad, en una serie de muestras de aceros recubiertas con capas de cobre, entre 5 y 200 µm, alcanzando valores de resolución en profundidad entre 7 y 9 veces por debajo del correspondiente valor del espesor de capa. Izmir et al [21] comparan el uso de los sistemas de "barrido" y "punto fijo" para determinar la difusión en la interfase de recubrimientos de NiCrAlY sobre aleaciones de alta temperatura, observando tanto la existencia de una difusión del aluminio de la capa hacia el substrato, como la difusión de algunos de los aleantes del substrato (cobalto, tántalo, molibdeno, wolframio…) hacia el recubrimiento.…”

Numerical and experimental depth profile analyses of coated and attached layers by laser-induced breakdown spectroscopy

“…The effects of key experimental parameters, such as laser energy and working distance, are characterized in Refs. [17][18][19]. Results in Ref.…”

“…It is shown later that there are no efficient differences between an attached layer and a coating one. Most of studies use normalized intensity (I N ) for analysis of the coating depth [11,12,[17][18][19]. In this case, the position of interface is defined as a point in which the normalized intensities of layer and substrate are equal.…”

Synthetic Samples Preparation to Identify Al2O3 Particles in Steel by Laser Ablation ICP Mass Spectrometry

“…[7][8][9][10] The real advantage, however, is the ability of the technique to provide information on spatial distribution in all three dimensions, dealing with inhomogeneous samples. The changing transient signals can provide information about the presence of heterogeneities, although the time delay in the sample transport system (including the sample cell volume) is a limiting factor, causing signal mixing during the transportation of the ablated material, and preventing accurate identification of the exact origin of every signal.…”