@Article{OliveiraReisOlivReis:2020:InHiNi,
author = "Oliveira, Aline Capella de and Reis, Joares Lidovino dos and
Oliveira, Rog{\'e}rio de Moraes and Reis, Danieli Aparecida
Pereira",
affiliation = "{Universidade Federal de S{\~a}o Paulo (UNIFESP)} and
{Universidade Federal de S{\~a}o Paulo (UNIFESP)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Universidade Federal
de S{\~a}o Paulo (UNIFESP)}",
title = "The Influence of high-temperature nitrogen plasma-based ion
implantation on niobium creep behavior",
journal = "Advances in Materials Science and Engineering",
year = "2020",
volume = "2020",
pages = "e9745082",
abstract = "Niobium has been considered for applications in the aerospace
sector, but its use at high temperatures is restricted, due to the
great affinity of refractory metals with oxygen, which results in
the formation of oxide layers and a decrease in their mechanical
resistances. In the present work, Nb samples were submitted to
High-Temperature Nitrogen Plasma-Based Ion Implantation
(HT-NPBII). The process runs at a working pressure between 3 and 4
mbar and negative high voltage pulses of 7 kV/30 mu s/300 Hz were
applied to samples heated to 1000 degrees C, at treatment times of
1 h, 4 h, and 8 h, respectively. Microstructural and mechanical
characterizations of the treated samples revealed the formation of
a layer of Nb2N, with 3.0 mu m thickness and increase in the
surface hardness from 225 HV for the untreated material up to
about 2498 HV, for samples treated during 8 h. Creep tests were
performed at 500 degrees C and with loads varying from 25 to 40
MPa. Results indicated a decrease in the secondary creep rate for
treated specimens when compared to the untreated ones. This
behavior can be attributed to the formation of a nitride layer on
the surface of Nb that acts as barrier to avoid the oxygen
diffusion into the material under high temperature conditions.",
doi = "10.1155/2020/9745082",
url = "http://dx.doi.org/10.1155/2020/9745082",
issn = "1687-8434",
language = "en",
targetfile = "oliveira_influence.pdf",
urlaccessdate = "25 abr. 2024"
}