@MastersThesis{LugoGonzález:2017:EsAdCo,
author = "Lugo Gonz{\'a}lez, Dubrazkha Carolina",
title = "Estudo da ader{\^e}ncia e do coeficiente de atrito de filmes de
DLC em Ti-6Al-4V com deposi{\c{c}}{\~a}o de interface de
sil{\'{\i}}cio para aplica{\c{c}}{\~a}o espacial",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2017",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2017-03-07",
keywords = "diamond-like carbon, ader{\^e}ncia, coeficiente de atrito,
lubrificante s{\'o}lido, PECVD, aplica{\c{c}}{\~a}o espacial,
diamond-like carbon (DLC), adhesion, friction coefficient, solid
lubricants, spatial aplication.",
abstract = "O estudo de filmes de Diamond-like Carbon (DLC) {\'e} de grande
interesse devido {\`a}s excelentes propriedades mec{\^a}nicas e
tribol{\'o}gicas que possibilitam a utiliza{\c{c}}{\~a}o dos
filmes de DLC como revestimentos protetores em diferentes
aplica{\c{c}}{\~o}es industriais, biom{\'e}dicas e espaciais.
No entanto, a grande desvantagem destes filmes {\'e} a baixa
ader{\^e}ncia quando s{\~a}o depositados sobre alguns substratos
met{\'a}licos devido ao estresse compressivo gerado no processo
de deposi{\c{c}}{\~a}o e {\`a}s diferen{\c{c}}as do
coeficiente de dilata{\c{c}}{\~a}o t{\'e}rmica entre o filme e
o substrato utilizado. Esta linha de pesquisa tinha como objetivo
principal obter filmes de DLC com elevada ader{\^e}ncia sobre o
substrato de liga de tit{\^a}nio Ti-6Al-4V, assim como filmes com
baixo coeficiente de atrito para aplica{\c{c}}{\~o}es espaciais.
Os filmes de DLC foram depositados sobre o substrato com a
utiliza{\c{c}}{\~a}o da t{\'e}cnica PECVD (Plasma Enhanced
Chemical Vapor Deposition) - DC pulsada modificada com a
incorpora{\c{c}}{\~a}o de um c{\'a}todo adicional que permite
deposi{\c{c}}{\~a}o de filmes com press{\~o}es em torno de
10\$^{-3}\$ Torr. Para o estudo da ader{\^e}ncia foram
realizadas varia{\c{c}}{\~o}es na tens{\~a}o e largura de pulso
da fonte de polariza{\c{c}}{\~a}o para a deposi{\c{c}}{\~a}o
de diferentes interfaces de sil{\'{\i}}cio amorfo. Logo, foi
estabelecida a condi{\c{c}}{\~a}o de ader{\^e}ncia
aceit{\'a}vel entre filmes de DLC e o substrato da liga de
tit{\^a}nio Ti-6Al-4V. Tamb{\'e}m foram realizadas
varia{\c{c}}{\~o}es da tens{\~a}o de deposi{\c{c}}{\~a}o dos
filmes de DLC com o objetivo de variar o conte{\'u}do de
hidrog{\^e}nio. Foi avaliada a ader{\^e}ncia dos filmes com a
utiliza{\c{c}}{\~a}o do padr{\~a}o VDI 3198 e com testes de
riscamento. Para avaliar a composi{\c{c}}{\~a}o qu{\'{\i}}mica
dos filmes foram utilizadas t{\'e}cnicas nucleares de feixe
i{\^o}nico. O coeficiente de atrito dos filmes foi avaliado no
modo rec{\'{\i}}proco em press{\~a}o atmosf{\'e}rica e de alto
v{\'a}cuo. Os resultados mostraram que entre todas as
metodologias de deposi{\c{c}}{\~a}o de interface de
sil{\'{\i}}cio, a que apresentou maior ader{\^e}ncia foi a
camada depositada com tens{\~a}o de polariza{\c{c}}{\~a}o de -
0,95 kV com a utiliza{\c{c}}{\~a}o de uma fonte de 20 kHz e
largura de pulso de 20 \$\mu\$s. Foi poss{\'{\i}}vel obter
filmes de DLC com teor de hidrog{\^e}nio de at{\'e} 40 \% e com
baixo coeficiente de atrito em alto v{\'a}cuo e
condi{\c{c}}{\~o}es de press{\~a}o atmosf{\'e}rica.
Tamb{\'e}m foram obtidos filmes com elevada dureza e com baixo
coeficiente de atrito nas duas atmosferas testadas. Os resultados
mostraram a grande potencialidade dos filmes de DLC para
aplica{\c{c}}{\~a}o espacial devido a sua elevada
ader{\^e}ncia, elevada qualidade estrutural e baixo coeficiente
de atrito. ABSTRACT: The study of Diamond-like Carbon (DLC) films
is of great interest due to their excellent mechanical and
tribological properties that allow the use of DLC films as
protective coatings in different applications such as industrial,
biomedical, and spatial. However, the great disadvantage of these
films is their low adhesion when they are grown on metallic
substrates due to the high compressive stress that arises during
film deposition process and the differences of the thermal
expansion coefficient between the film and the substrate. This
research aimed mainly to obtain DLC films with high adhesion on a
Ti-6Al-4V titanium alloy substrate and with low friction
coefficient for space applications. The DLC films were deposited
on the substrate using the PECVD (Plasma Enhanced Chemical Vapor
Deposition) - DC pulsed technique modified with an incorporation
of an additional cathode that enables films deposition at very low
pressures around 10\$^{-3}\$Torr. For the adhesion study,
amorphous silicon interfaces were deposited with different
voltages and with different pulse widths of the polarization
source.Then, it was established the acceptable adhesion condition
between DLC films and the Ti-6Al-4V titanium alloy substrate.
Furthermore, a variation of the deposition voltage of the DLC
films was carried out in order to vary the hydrogen content of the
films. The adhesion of the films was evaluated using the standard
VDI 3198 and the critical load obtained by scratch tests. Nuclear
techniques of ionic beam were used to evaluate the chemical
composition of the films. The friction coefficient of the films
was evaluated in reciprocating mode in ambient and high vacuum
atmospheres. The results showed that among all the silicon
interface deposition methodologies the one that presented the
highest adhesion was the layer deposited with bias voltage of -
0.95 kV and a power supply at 20 kHz with a pulse width of 20
\$\mu\$s. It was possible to obtain DLC films with a hydrogen
content up to 40\% and with low friction coefficient under high
vacuum and atmospheric pressure conditions. Results showed that
DLC films can act as solid lubricants for spatial applications due
to their high adhesion, high structural quality, and low friction
coefficient in vacuum and environmental conditions.",
committee = "Trava-Airoldi, Vladimir Jesus (presidente/orientador) and
Ram{\'{\i}}rez, Marco and Martins, Gislene",
copyholder = "SID/SCD",
englishtitle = "Study of the adherence and the friction coefficient of DLC films
on Ti-6Al-4V with deposition of silicon interface for space
applications",
language = "pt",
pages = "148",
ibi = "8JMKD3MGP3W34P/3NFRGN5",
url = "http://urlib.net/ibi/8JMKD3MGP3W34P/3NFRGN5",
targetfile = "publicacao.pdf",
urlaccessdate = "27 abr. 2024"
}