Influência das espécies ativas na absorção de intersticiais durante a carbonitretação a plasma do TI
Physical-chemical properties of Ti are sensible to the presence of interstitial elements. In the case of thermochemical treatments plasma assisted, the influence of different active species is not still understood. In order to contribute for such knowledge, this work purposes a study of the role...
Sábháilte in:
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| Rannpháirtithe: | |
| Formáid: | Dissertação |
| Teanga: | por |
| Foilsithe / Cruthaithe: |
Universidade Federal do Rio Grande do Norte
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| Ábhair: | |
| Rochtain ar líne: | https://repositorio.ufrn.br/jspui/handle/123456789/12712 |
| Clibeanna: |
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| Achoimre: | Physical-chemical properties of Ti are sensible to the presence of interstitial elements.
In the case of thermochemical treatments plasma assisted, the influence of different active
species is not still understood. In order to contribute for such knowledge, this work purposes a
study of the role played by the active species atmosphere into the Ar N2 CH4
carbonitriding plasma. It was carried out a plasma diagnostic by OES (Optical Emission
Spectroscopy) in the z Ar y N2 x CH4 plasma mixture, in which z, y and x indexes
represent gas flow variable from 0 to 4 sccm (cm3/min). The diagnostic presents abrupt
variations of emission intensities associated to the species in determined conditions.
Therefore, they were selected in order to carry out the chemical treatment and then to
investigate their influences. Commercial pure Ti disks were submitted to plasma
carbonitriding process using pre-established conditions from the OES measurements while
some parameters such as pressure and temperature were maintained constant. The
concentration profiles of interstitial elements (C and N atoms) were determined by Resonant
Nuclear Reaction Analysis (NRA) resulting in a depth profile plots. The reactions used were
15N(ρ,αγ)12C and 12C(α,α)12C. GIXRD (Grazing Incidence X-Ray Diffraction) analysis was
used in order to identify the presence of phases on the surface. Micro-Raman spectroscopy
was used in order to qualitatively study the carbon into the TiCxN1 structure. It has been
verified which the density species effectively influences more the diffusion of particles into
the Ti lattice and characteristics of the layer formed than the gas concentration. High intensity
of N2
+ (391,4 nm) and CH (387,1 nm) species promotes more diffusion of C and N. It was
observed that Hα (656,3 nm) species acts like a catalyzer allowing a deeper diffusion of
nitrogen and carbon into the titanium lattice. |
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