Redução in situ de NIO durante a sinterização de misturas NI/NIO produzidas por metalurgia do pó
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 nic...
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| Formato: | Dissertação |
| Idioma: | por |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/19593 |
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| Resumo: | 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 |
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