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Previous issue date: 2012-06-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / As ligas de n?quel s?o largamente utilizadas na produ??o de diversos materiais,
sobretudo, aqueles que necessitam de resist?ncia mec?nica associada ? resist?ncia
? corros?o, como por exemplo, os a?os inoxid?veis. Outro uso do n?quel ? a
produ??o de ligas sinterizadas a partir de p? de n?quel met?lico. Uma alternativa
promissora ? produ??o de componentes sinterizados de n?quel com importante
redu??o de custos do material de partida ? o emprego de misturas de p?s do tipo NiNiO.
Este trabalho teve por objetivo o estudo da redu??o in situ de NiO durante a
sinteriza??o de misturas Ni/NiO produzidas por metalurgia do p?. As misturas foram
processadas pela t?cnica de metalurgia do p? e pr?-sinterizadas em atmosfera
redutora de hidrog?nio. As amostras Ni+15%NiO, Ni+25%NiO e Ni+35%NiO foram
estudadas e comparadas com amostras sinterizadas apenas a partir de Ni met?lico.
Foram realizados ensaios dilatom?tricos para estudo das condi??es de sinteriza??o
das misturas. O material consolidado foi analisado quanto ? sua microestrutura e
microdureza. As curvas de dilatometria mostraram que a adi??o de ?xido de n?quel
em todas as composi??es ativa a sinteriza??o das misturas estudadas. Nos testes
de microdureza foram realizadas indenta??es em pontos distintos da superf?cie das
amostras. Todas as composi??es apresentaram valores de microdureza pr?ximos ao
do material consolidado a partir de n?quel met?lico. Contudo, as amostras contendo
Ni+35%NiO, apresentaram grande dispers?o desses valores. A an?lise
microestrutural do material mostrou uma maior concentra??o de vazios e presen?a
de ?xidos residuais nas misturas da composi??o Ni+35%NiO. As amostras contendo
Ni+15%NiO apresentaram caracter?sticas microestruturais e propriedades
mec?nicas semelhantes ao n?quel met?lico consolidado sob as mesmas condi??es
das composi??es estudadas neste trabalho e, portanto, apresentaram grande
potencial para produ??o de ligas sinterizadas de n?quel / The nickel alloys are widely used in the production of various materials, especially
those that require mechanical strength characteristics associated with resistance to
corrosion, for example, the stainless steel. Another use is the production of
nickel alloy sintered from powder of metallic nickel. A promising alternative for the
production of sintered components of nickel with an important reduction in costs of
starting material is the use of mixtures of powders of Ni-NiO. This work aimed to
study in situ reduction of NiO during sintering mixtures of Ni / NiO produced by
powder metallurgy. The nickel mixtures have been processed by the technique of
powder metallurgy and were pre-sintered in an oven under plasma reducing
atmosphere of hydrogen. Mixtures Ni +15%NiO, Ni +25%NiO and Ni +35%NiO were
studied and compared with samples consisting only of metallic Ni. Dilatometric tests
were performed to study the sintering conditions of the mixtures. The consolidated
material was analyzed for their microstructure and microhardness. Dilatometry
graphs showed that the addition of nickel oxide in all compositions the active
sintering the mixtures studied. In tests of microhardness indentations were made at
different points of the sample surface. All compositions showed microhardness
values close to the consolidated material from metallic nickel. However, sample
containing Ni+35% NiO, showed a large dispersion of the values of microhardness
tests performed at different points of the sample surface. Microstructural analysis of
the material showed a higher concentration of voids and the presence of oxides in
the waste composition of the mixtures Ni 35% NiO. The samples containing
Ni+15%NiO showed microstructural characteristics and mechanical properties similar
to metallic nickel consolidated under the same conditions of the compositions studied
in this work and therefore had great potential for production of sintered nickel alloys
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19593 |
| Date | 04 June 2012 |
| Creators | Dantas, Elis?ngela Barros |
| Contributors | 15724520800, http://lattes.cnpq.br/0022988322449627, Binder, Cristiano, 02607912962, http://lattes.cnpq.br/0692818548181755, Peres, Maur?cio Mhirdaui, 17536268890, http://lattes.cnpq.br/3068024292581677, Klein, Alo?sio Nelmo, Martinelli, Antonio Eduardo |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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