Microwave plasma nitriding of pure iron

Abstract

Studies on plasma-nitrided iron by scanning electron microscopy, glancing angle x-ray diffraction, and x-ray photoelectron spectroscopy This article presents the results of a study of the plasma characteristics of an electron cyclotron resonance plasma source used for nitriding pure Fe. Diagnostic measurements, using optical emission spectroscopy, Langmuir probes, and an ion analyzer, were recorded as functions of the working pressure (2 -8ϫ10 Ϫ4 Torr͒ and the external magnetic field near the substrate ͑from the extremes of highly compressed and divergent plasma fluxes͒. It was observed that the plasma source is capable of producing high density discharges, about 5ϫ10 11 cm Ϫ3 and ion energies about 15-48 eV. The ion energy was highest for the case of a divergent plasma (ϳ45 eV͒. The most abundant excited radicals produced in the N/H discharges were the NH, N 2 and N 2 ϩ species. Experiments for nitriding of Fe showed the formation of distinct material structures dependent on the plasma conditions. Conditions were found for which it was possible to form almost single phases of Fe 3 N and Fe 16 N 2 in the sample surface.

Density and temperature of N atoms in the afterglow of a microwave discharge measured by a two-photon laser-induced fluorescence technique

“…where σ (2) is the two-photon absorption cross section, hν is the UV photon energy, n N is the ground state nitrogen atom density, I laser is the laser energy, A is the Einstein transition probability for spontaneous emission, τ is the lifetime of the excited level, and f is a factor which takes into account the geometry and the spectral response of the optical imaging and detection system. The excited-state lifetime τ accounts for both radiative processes and non-radiative processes, i.e.…”

“…One of the main fields of application of such plasmas is surface treatment. Nitrogen-containing plasmas are widely used for the treatment of iron [1,2], steel, and alloys [3][4][5]. The nitriding process is performed either within the discharge or in the afterglow.…”

Electrical and spectroscopic characterizations of a low pressure argon discharge created by a broad-band helical coupling device

“…Techniques based on non-equilibrium plasmas are still of growing interest in a wide field of industrial applications: surface treatments applied to metals [1,2] or non-metals [3][4][5] to improve their properties (hardness, resistance to corrosion and wear), sterilization of surfaces of medical instruments [6,7], cleaning of oxidized steel surfaces [8] or generation of nanostructures such as nanotubes [9] or crystalline nanoparticles [10]. Typically, these applications require reactive gases with complex chemistries, which are strongly influenced by the discharge dynamics.…”

${\gamma}$ -Fe phase plasma-induced on the surface of thin S3A alloy ribbons

“…The plasma process (PP) was carried out in a microwave electron cyclotron resonance (ECR) plasma device, described in detail elsewhere [7]. Either pure N 2 gas (PP1) or a mixture of Ar and N 2 gases in a proportion of 60/40, (PP2) was used to produce the cold plasma under a pressure of 8×10 −4 Torr [7] and an input power (kept constant) of 450 Watts [7]. Under these conditions the plasma density of 2×10 11 ions/cm 3 was established.…”