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Previous issue date: 2013-08-09 / The technique of ion nitriding, despite being fully consolidated in the industry, has
great limitations when applied to the treatment of small parts. This is because effects
that occur due to non-uniformity of the electric field, generate localized heating in
parts, damaging the uniformity of nitrided layer. In addition, because the samples are
treated static parts thereof are untreated. To expand the use of plasma nitriding, this
work presents the development, assembly and testing of a prototype plasma reactor
with rotatory cathodic cage [patent pending], able to meet these needs, giving the
material a uniform treatment and opening doors to industrial scale production. The
samples tested with hexagonal nuts are 6.0 mm in diameter, made of stainless steel
AISI 304 nitrided at a pressure of 1 mbar in an atmosphere of 20% H2 + 80% N2 for
1 h. After treatment, testing visual inspection, optical microscopy and microhardness
were carried out to check the effectiveness of the process for uniformity and
hardness of the parts. All samples exhibited uniform color, and matte brownish,
unlike the untreated samples, silver color and gloss. The hardness of the surface (top
and sides) was 65% and even higher than the original hardness. The nitrided layer
showed great uniformity in microstructure and thickness. It is concluded, therefore,
that the unit was effective constructed for the purposes for which it was designed / A t?cnica de nitreta??o i?nica, apesar de estar plenamente consolidada na ind?stria,
possui grande limita??o quando aplicada ao tratamento de pe?as pequenas. Isso
acontece porque efeitos que ocorrem devido a n?o uniformidade do campo el?trico,
geram aquecimentos localizados nas pe?as, prejudicando a uniformidade da
camada nitretada. Al?m disso, pelo fato das amostras serem tratadas de maneira
est?tica, partes das mesmas ficam sem tratamento. Para ampliar o uso da nitreta??o
a plasma, este trabalho apresenta o desenvolvimento, montagem e teste de um
prot?tipo de reator de plasma com gaiola cat?dica rotat?ria [patente requerida],
capaz de atender a essas necessidades, conferindo ao material um tratamento
uniforme e abrindo portas ? produ??o em escala industrial. As amostras submetidas
ao teste s?o porcas sextavadas de 6,0 mm de di?metro, fabricadas em a?o
inoxid?vel AISI 304, nitretadas numa press?o de 1 mbar em atmosfera de 20%H2 +
80%N2, durante 1 h. Ap?s o tratamento, ensaios de inspe??es visuais, microscopia
?tica e microdureza foram realizadas a fim de conferir a efic?cia do processo quanto
? uniformidade e dureza das pe?as. Todas as amostras apresentaram cor uniforme,
amarronzada e fosca, ao contr?rio das amostras sem tratamento, de cor prata e
brilhosas. A dureza da superf?cie (topo e lateral) mostrou-se uniforme e 65% superior
? dureza original, considerado o tempo de tratamento. A camada nitretada
apresentou grande uniformidade na microestrutura e espessura. Conclui-se,
portanto, que o equipamento constru?do mostrou efic?cia para os fins a que foi
designado
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/15717 |
| Date | 09 August 2013 |
| Creators | Ara?jo Filho, Lino |
| Contributors | CPF:09621199468, http://lattes.cnpq.br/7441669258580942, Fontes, Francisco de Assis Oliveira, CPF:20300190468, http://lattes.cnpq.br/9043538628554844, Ara?jo, Francisco Odolberto de, CPF:80752730444, Alves J?nior, Clodomiro |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Engenharia Mec?nica, UFRN, BR, Tecnologia de Materiais; Projetos Mec?nicos; Termoci?ncias |
| 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 |
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