Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP)
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFU |
Texto Completo: | https://repositorio.ufu.br/handle/123456789/21489 http://dx.doi.org/10.14393/ufu.te.2018.774 |
Resumo: | Due to its high cost, deposition of Inconel 625 onto cheaper substrates by different techniques can be an economically viable alternative. In this work, PTAP (Plasma Transferred Arc – Powder) was used to deposit Inconel 625 onto carbon steel substrates. Parameterization of the process resulted in thick deposits (> 3 mm). Current, welding speed and powder feed rate were varied within a narrow range to identify an operational envelope within which good deposits could be produced, their quality was assessed both in terms of adequate macro and microstructure. Macrographic analysis allowed the measurement of the geometric characteristics of the beads. Two groups were identified, one with lower dilution (<6%) and another with greater dilution (7.5 to 11.9%). Microhardness profiles SEM-EDX analysis and X-ray diffraction characterized the microstructure of the deposits, which exhibited dendritic microstructures. Microsegregation of Nb in the interdendritic regions resulted in the formation of eutectic phases constituted of a Ni-Cr matrix and second-phase particles rich in Nb and Mo. A fixed-sphere microabrasometer was employed to assess the abrasion resistance of the deposits, using a zirconia ball with controlled roughness (Ra between 0.32 and 0.38 μm) and a slurry with a concentration of 20% of SiO2 particles. The tribological conditions used in the microabrasion tests resulted in mixed wear mechanisms, involving predominantly sliding but also rolling of the abrasive particles. No effect of the dilution of the deposits on their abrasion resistance was found. To evaluate their corrosion resistance, potentiodynamic tests were carried out using 3.5% NaCl, NaCl + FeCl3 and NaCl + H2SO4 solutions. The H2SO4 solution showed to be the most aggressive, for which it was possible to identify variations in current density between the groups with different dilutions, whereas no significant differences were identified for the other electrochemical variables. For the microabrasion-corrosion, the slurries contained SiO2 particles added to the same solutions used in the corrosion tests. The wear coefficients measured under microabrasion-corrosion conditions were higher than under pure microabrasion conditions, evidencing a positive synergy between microabrasion and corrosion. On the other hand, the friction coefficients reduced when compared with pure microabrasion for all the slurries tested, suggesting that the corrosion products form a film with relatively low friction coefficient. Besides, for the slurry containing the most aggressive solution (NaCl + H2SO4), there was a small effect of dilution on the electrochemical variables, where the deposits with higher dilution showed a current density greater than the group with the lowest dilution (which characterizes the lower corrosion resistance of this group). |
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Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP)Microabrasion-Corrosion of Inconel 625 Coatings deposited by Plasma Powder (PTAP)PTAPInconel 625MicroabrasãoCorrosãoTribocorrosãoMicro-abrasionCorrosionTribocorrosionEngenharia mecânicaCorrosão e anticorrosivosLigas de níquelCNPQ::CIENCIAS EXATAS E DA TERRADue to its high cost, deposition of Inconel 625 onto cheaper substrates by different techniques can be an economically viable alternative. In this work, PTAP (Plasma Transferred Arc – Powder) was used to deposit Inconel 625 onto carbon steel substrates. Parameterization of the process resulted in thick deposits (> 3 mm). Current, welding speed and powder feed rate were varied within a narrow range to identify an operational envelope within which good deposits could be produced, their quality was assessed both in terms of adequate macro and microstructure. Macrographic analysis allowed the measurement of the geometric characteristics of the beads. Two groups were identified, one with lower dilution (<6%) and another with greater dilution (7.5 to 11.9%). Microhardness profiles SEM-EDX analysis and X-ray diffraction characterized the microstructure of the deposits, which exhibited dendritic microstructures. Microsegregation of Nb in the interdendritic regions resulted in the formation of eutectic phases constituted of a Ni-Cr matrix and second-phase particles rich in Nb and Mo. A fixed-sphere microabrasometer was employed to assess the abrasion resistance of the deposits, using a zirconia ball with controlled roughness (Ra between 0.32 and 0.38 μm) and a slurry with a concentration of 20% of SiO2 particles. The tribological conditions used in the microabrasion tests resulted in mixed wear mechanisms, involving predominantly sliding but also rolling of the abrasive particles. No effect of the dilution of the deposits on their abrasion resistance was found. To evaluate their corrosion resistance, potentiodynamic tests were carried out using 3.5% NaCl, NaCl + FeCl3 and NaCl + H2SO4 solutions. The H2SO4 solution showed to be the most aggressive, for which it was possible to identify variations in current density between the groups with different dilutions, whereas no significant differences were identified for the other electrochemical variables. For the microabrasion-corrosion, the slurries contained SiO2 particles added to the same solutions used in the corrosion tests. The wear coefficients measured under microabrasion-corrosion conditions were higher than under pure microabrasion conditions, evidencing a positive synergy between microabrasion and corrosion. On the other hand, the friction coefficients reduced when compared with pure microabrasion for all the slurries tested, suggesting that the corrosion products form a film with relatively low friction coefficient. Besides, for the slurry containing the most aggressive solution (NaCl + H2SO4), there was a small effect of dilution on the electrochemical variables, where the deposits with higher dilution showed a current density greater than the group with the lowest dilution (which characterizes the lower corrosion resistance of this group).CNPq - Conselho Nacional de Desenvolvimento Científico e TecnológicoTese (Doutorado)Devido ao seu elevado custo, o Inconel 625 é comumente depositado em substratos mais baratos por meio de diferentes técnicas, sendo uma alternativa economicamente viável. Neste trabalho, o processo PTAP (Plasma Transferred Arc – Powder) foi utilizado para depositar Inconel 625 sobre substratos de aço carbono. A parametrização do processo resultou em depósitos espessos (> 3 mm). Corrente, velocidade de soldagem e taxa de alimentação foram variados dentro de uma faixa estreita para identificar um envelope operacional de parâmetros dentro do qual fosse possível produzir depósitos de elevada qualidade do ponto de vista macro e microestrutural. Análises macrográficas permitiram a medição das características geométricas dos cordões. Foram identificados dois grupos, um com diluição menor (<6%) e outro com maior (7,5-11,9%). Perfis de microdureza e análise por MEV-EDX e difração de raios-X permitiram caracterizar a microestrutura dos depósitos, os quais exibiram microestruturas dendríticas. Microsegregação de Nb nas regiões interdendríticas resultou na formação de fases eutéticas constituídas de uma matriz de níquel e cromo e partículas de segunda fase ricas em Nb e Mo. Para avaliar a resistência à abrasão dos depósitos produzidos, utilizou-se um microabrasômetro de esfera fixa, com esfera de zircônia e rugosidade controlada (Ra entre 0,32 e 0,38 µm) com solução de concentração de 20% de SiO2. As condições tribológicas utilizadas nos ensaios de microabrasão resultaram em mecanismos de desgaste mistos, com predominância de deslizamento, mas também com rolamento de partículas. Não foram observadas diferenças na resistência à microabrasão em função da diluição dos depósitos. Na avaliação a resistência à corrosão, foram utilizados testes potenciodinâmicos com soluções 3,5% NaCl, NaCl + FeCl3 e de NaCl + H2SO4. A solução com H2SO4 se mostrou mais agressiva que as demais, sendo possível identificar variações na densidade de corrente entre os dois grupos com diferentes diluições, ao passo que não se identificou diferenças significativas quanto às demais variáveis eletroquímicas. Os ensaios de microabrasão-corrosão utilizaram as mesmas soluções dos ensaios de corrosão, às quais foram adicionadas abrasivos. Os coeficientes de desgaste sob condições de microabrasão-corrosão foram mais elevados que em condições de abrasão pura, evidenciando uma sinergia positiva entre abrasão e corrosão. Por outro lado, houve redução do coeficiente de atrito para as três diferentes lamas testadas, sugerindo que os produtos da corrosão formam um filme de coeficiente de atrito relativamente baixo. Além disso, para a lama contendo a solução mais agressiva (NaCl + H2SO4), houve um pequeno efeito da diluição dos depósitos nas variáveis eletroquímicas medidas, sendo que as amostras com maior diluição apresentaram uma densidade de corrente uma ordem de grandeza maior que o grupo de menor diluição (o que caracteriza a menor resistência à corrosão desse grupo).Universidade Federal de UberlândiaBrasilPrograma de Pós-graduação em Engenharia MecânicaLuz, Temístocles de Sousahttp://lattes.cnpq.br/4392077368620764Costa, Henara Lillianhttp://lattes.cnpq.br/8973820249465087Silva Junior, Washington Martins dahttp://lattes.cnpq.br/2993173987424895Silva Jr, Washington da Silvahttp://lattes.cnpq.br/2993173987424895Canobre, Sheila Cristinahttp://lattes.cnpq.br/1606997598547152Farias, Maria Cristina Moréhttp://lattes.cnpq.br/8512921714632775Tschipschin, André Paulohttp://lattes.cnpq.br/2163698776105146Santos, Regina Paula Garcia2018-06-11T14:50:57Z2018-06-11T14:50:57Z2018-02-02info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfSANTOS, R.P.G., Microabrasão Corrosão de Revestimentos de Inconel 625 depositados por Plasma Pó (PTAP), Uberlândia. 2018. 178 f. Tese de Doutorado, Universidade Federal de Uberlândia, Uberlândia 2018. DOI http://dx.doi.org/10.14393/ufu.te.2018.774.https://repositorio.ufu.br/handle/123456789/21489http://dx.doi.org/10.14393/ufu.te.2018.774porinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFUinstname:Universidade Federal de Uberlândia (UFU)instacron:UFU2021-10-15T20:25:02Zoai:repositorio.ufu.br:123456789/21489Repositório InstitucionalONGhttp://repositorio.ufu.br/oai/requestdiinf@dirbi.ufu.bropendoar:2021-10-15T20:25:02Repositório Institucional da UFU - Universidade Federal de Uberlândia (UFU)false |
dc.title.none.fl_str_mv |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) Microabrasion-Corrosion of Inconel 625 Coatings deposited by Plasma Powder (PTAP) |
title |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) |
spellingShingle |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) Santos, Regina Paula Garcia PTAP Inconel 625 Microabrasão Corrosão Tribocorrosão Micro-abrasion Corrosion Tribocorrosion Engenharia mecânica Corrosão e anticorrosivos Ligas de níquel CNPQ::CIENCIAS EXATAS E DA TERRA |
title_short |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) |
title_full |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) |
title_fullStr |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) |
title_full_unstemmed |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) |
title_sort |
Microabrasão-Corrosão de Revestimentos de Inconel 625 Depositados por Plasma Pó (PTAP) |
author |
Santos, Regina Paula Garcia |
author_facet |
Santos, Regina Paula Garcia |
author_role |
author |
dc.contributor.none.fl_str_mv |
Luz, Temístocles de Sousa http://lattes.cnpq.br/4392077368620764 Costa, Henara Lillian http://lattes.cnpq.br/8973820249465087 Silva Junior, Washington Martins da http://lattes.cnpq.br/2993173987424895 Silva Jr, Washington da Silva http://lattes.cnpq.br/2993173987424895 Canobre, Sheila Cristina http://lattes.cnpq.br/1606997598547152 Farias, Maria Cristina Moré http://lattes.cnpq.br/8512921714632775 Tschipschin, André Paulo http://lattes.cnpq.br/2163698776105146 |
dc.contributor.author.fl_str_mv |
Santos, Regina Paula Garcia |
dc.subject.por.fl_str_mv |
PTAP Inconel 625 Microabrasão Corrosão Tribocorrosão Micro-abrasion Corrosion Tribocorrosion Engenharia mecânica Corrosão e anticorrosivos Ligas de níquel CNPQ::CIENCIAS EXATAS E DA TERRA |
topic |
PTAP Inconel 625 Microabrasão Corrosão Tribocorrosão Micro-abrasion Corrosion Tribocorrosion Engenharia mecânica Corrosão e anticorrosivos Ligas de níquel CNPQ::CIENCIAS EXATAS E DA TERRA |
description |
Due to its high cost, deposition of Inconel 625 onto cheaper substrates by different techniques can be an economically viable alternative. In this work, PTAP (Plasma Transferred Arc – Powder) was used to deposit Inconel 625 onto carbon steel substrates. Parameterization of the process resulted in thick deposits (> 3 mm). Current, welding speed and powder feed rate were varied within a narrow range to identify an operational envelope within which good deposits could be produced, their quality was assessed both in terms of adequate macro and microstructure. Macrographic analysis allowed the measurement of the geometric characteristics of the beads. Two groups were identified, one with lower dilution (<6%) and another with greater dilution (7.5 to 11.9%). Microhardness profiles SEM-EDX analysis and X-ray diffraction characterized the microstructure of the deposits, which exhibited dendritic microstructures. Microsegregation of Nb in the interdendritic regions resulted in the formation of eutectic phases constituted of a Ni-Cr matrix and second-phase particles rich in Nb and Mo. A fixed-sphere microabrasometer was employed to assess the abrasion resistance of the deposits, using a zirconia ball with controlled roughness (Ra between 0.32 and 0.38 μm) and a slurry with a concentration of 20% of SiO2 particles. The tribological conditions used in the microabrasion tests resulted in mixed wear mechanisms, involving predominantly sliding but also rolling of the abrasive particles. No effect of the dilution of the deposits on their abrasion resistance was found. To evaluate their corrosion resistance, potentiodynamic tests were carried out using 3.5% NaCl, NaCl + FeCl3 and NaCl + H2SO4 solutions. The H2SO4 solution showed to be the most aggressive, for which it was possible to identify variations in current density between the groups with different dilutions, whereas no significant differences were identified for the other electrochemical variables. For the microabrasion-corrosion, the slurries contained SiO2 particles added to the same solutions used in the corrosion tests. The wear coefficients measured under microabrasion-corrosion conditions were higher than under pure microabrasion conditions, evidencing a positive synergy between microabrasion and corrosion. On the other hand, the friction coefficients reduced when compared with pure microabrasion for all the slurries tested, suggesting that the corrosion products form a film with relatively low friction coefficient. Besides, for the slurry containing the most aggressive solution (NaCl + H2SO4), there was a small effect of dilution on the electrochemical variables, where the deposits with higher dilution showed a current density greater than the group with the lowest dilution (which characterizes the lower corrosion resistance of this group). |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-06-11T14:50:57Z 2018-06-11T14:50:57Z 2018-02-02 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
SANTOS, R.P.G., Microabrasão Corrosão de Revestimentos de Inconel 625 depositados por Plasma Pó (PTAP), Uberlândia. 2018. 178 f. Tese de Doutorado, Universidade Federal de Uberlândia, Uberlândia 2018. DOI http://dx.doi.org/10.14393/ufu.te.2018.774. https://repositorio.ufu.br/handle/123456789/21489 http://dx.doi.org/10.14393/ufu.te.2018.774 |
identifier_str_mv |
SANTOS, R.P.G., Microabrasão Corrosão de Revestimentos de Inconel 625 depositados por Plasma Pó (PTAP), Uberlândia. 2018. 178 f. Tese de Doutorado, Universidade Federal de Uberlândia, Uberlândia 2018. DOI http://dx.doi.org/10.14393/ufu.te.2018.774. |
url |
https://repositorio.ufu.br/handle/123456789/21489 http://dx.doi.org/10.14393/ufu.te.2018.774 |
dc.language.iso.fl_str_mv |
por |
language |
por |
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info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Uberlândia Brasil Programa de Pós-graduação em Engenharia Mecânica |
publisher.none.fl_str_mv |
Universidade Federal de Uberlândia Brasil Programa de Pós-graduação em Engenharia Mecânica |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da UFU instname:Universidade Federal de Uberlândia (UFU) instacron:UFU |
instname_str |
Universidade Federal de Uberlândia (UFU) |
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UFU |
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UFU |
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Repositório Institucional da UFU |
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Repositório Institucional da UFU |
repository.name.fl_str_mv |
Repositório Institucional da UFU - Universidade Federal de Uberlândia (UFU) |
repository.mail.fl_str_mv |
diinf@dirbi.ufu.br |
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1805569619883196416 |