Made available in DSpace on 2014-12-17T14:06:57Z (GMT). No. of bitstreams: 1
AntonioNF_DISSERT.pdf: 3720151 bytes, checksum: 9b23d51efb071c929717b8ea4387b379 (MD5)
Previous issue date: 2011-06-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / 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. / As propriedades f?sico-qu?micas do Ti s?o sens?veis ? presen?a de intersticiais. No
caso do tratamento termoqu?mico auxiliado por plasma, a influ?ncia das diferentes esp?cies
ativas ainda n?o ? bem entendida. A fim de colaborar para tal conhecimento, esse trabalho
prop?e um estudo das esp?cies ativas do plasma carbonitretante de N2+Ar+CH4. Foi realizado
o diagn?stico por espectroscopia de emiss?o ?ptica (OES) do plasma na mistura
xAr+yN2+zCH4, onde x, y e z s?o fluxos vari?veis de 0 a 4 sccm (cm3/min.). Esse
diagn?stico apresentou varia??es abruptas de intensidades de emiss?o das esp?cies em
determinadas condi??es e estas foram selecionadas para realizar o tratamento termoqu?mico e
assim investigar suas influ?ncias. Em seguida, discos de Ti comercialmente puros foram
submetidos ao processo de carbonitreta??o por plasma com as condi??es pr?-estabelecidas
pelo diagn?stico de plasma enquanto que os par?metros de press?o e temperatura foram
mantidos constantes. O perfil de concentra??o dos intersticiais, carbono e nitrog?nio, foi
determinado por rea??o nuclear ressonante (NRA) resultando numa curva de perfil em
profundidade. As rea??es usadas foram 15N(ρ,αγ)12C e 12C(α,α)12C. Utilizou-se difra??o de
raios-X em ?ngulo rasante (GIDRX) para identificar as fases presentes na superf?cie. A
espectroscopia micro-Raman foi usada para estudar, de forma qualitativa a estrutura do
carbono no TiCxN1-xVerificou-se que a densidade das esp?cies influencia, de maneira mais
efetiva que o fluxo de g?s, no processo de difus?o e nas caracter?sticas da camada formada.
Alta intensidade das esp?cies N2
+ (391,4 nm) e CH (387,1 nm) favorecem a difus?o dos
intersticiais C e N. Foi observado que o Hα (656,3 nm) atua como catalisador permitindo a
difus?o em maiores profundidades desses intersticiais na estrutura do Ti.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12712 |
| Date | 06 June 2011 |
| Creators | Nunes Filho, Ant?nio |
| Contributors | CPF:09621199468, http://lattes.cnpq.br/7441669258580942, Guerra Neto, Cust?dio Leopoldino Brito, CPF:46658564434, http://lattes.cnpq.br/5387010100082241, Vasconcellos, Marcos Ant?nio Zen, CPF:16741773053, http://lattes.cnpq.br/7534190511246668, Alves J?nior, Clodomiro |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncia e Engenharia de Materiais, UFRN, BR, Processamento de Materiais a partir do P?; Pol?meros e Comp?sitos; Processamento de Materiais a part |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
Page generated in 0.0024 seconds