Depth profile studies of ZrTiN coatings by laser ablation inductively coupled plasma mass spectrometry

Abstract

The feasibility of depth profiling was studied by using a 193-nm ArF* excimer laser ablation system (GeoLas, MicroLas, Goettingen, Germany) with a lens array-based beam homogenizer in combination with an ICP-QMS Agilent 7500. Two ablation cells (20 and 1.5 cm3) were compared at the laser repetition rate of 1 Hz, laser beam energy of 135 mJ and the carrier gas flow rate 1.5 L min(-1) He + 0.78 L min(-1) Ar. The ablation cell dimensions are important parameters for signal tailing; however, very small cell volumes (e.g. 1.5 cm3) may cause memory effects, which can be probably explained by dominant inertial losses of aerosol on cell walls with its delayed mobilization. The 20-cm3 ablation cell seems to be appropriate for depth profiling by continuous single-hole drilling. The study of the influence of the pit diameter magnitude on the waning and emerging signals under small crater depth/diameter aspect ratios, which range between 0.75 and 0.0375 for the 3-microm-thick coatings and pit diameters 4-80 microm, revealed that the steady-state signals of pure coating and pure substrate (out of interface) were obtained at crater diameters between 20 and 40 microm. Depth resolution defined by means of slopes of tangents in the layer interface region depend on the pit diameter and has an optimum value between 20 and 40 microm and gives 0.6 microm for the 20-microm pit. In-depth variation of concentration of coating constituent (Ti) was proved to be almost identical with two different laser/ICP systems.

Feasibility of depth profiling of Zn-based coatings by laser ablation inductively coupled plasma optical emission and mass spectrometry using infrared Nd:YAG and ArF* lasers

“…2b). Taking into account our preceding results obtained with 3-Am ZrTiN coatings when ablated by homogenized UV-LA [34], we can conclude that depth resolution is materialdependent. No tailing of coating constituents Zr or Ti was observed and the depth resolution varied between 0.6 and 1.0 Am, which might be related to significantly higher melting point of the coating (e.g.…”

“…With irradiated spot diameters 40, 80 and 120 Am, energy per pulse delivered to the target surface is equal to 0.075, 0.300 and 0.670 mJ, respectively. The corresponding irradiance is 15.8 MW/cm 2 , which is the value of the same order of magnitude as irradiances used for depth profiling of Zn coatings on steel [26] or Cu and Ni plating on brass [30] by LIBS, and for LA-ICP-MS depth profiling of titanium based coatings (TiN, TiC, TiAlN) and WC/Co coatings [23] or ZrTiN coatings on steel [34] by using the same laser/homogenizer system.…”

Femtosecond laser ablation inductively coupled plasma mass spectrometry: Fundamentals and capabilities for depth profiling analysis

“…Additionally, the feasibility of depth-profiling of ZrTiN coatings (3 mm) on steel, using the 193 nm ArF* excimer laser in combination with an ICP-QMS, has also been studied (Kanický, Kuhn, & Günther, 2004). Depth resolution, defined by means of described method of maximum slope of tangents in the layer interface region (Plotnikov et al, 2001), was calculated to be 0.6 mm.…”

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

“…Con el quadrupolo obtienen una resolución en profundidad ≤ 25 µm (calculada a partir de las curvas intensidadtiempo), mientras que con el de tiempo de vuelo llegan a una resolución de 0,20 µm por pulso láser. 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.…”