Navegando por Autor "Araújo, Anthunes Íkaro de"
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Artigo A novel technology to deposition diamond-like carbon thin films: cathodic cylinder plasma deposition(JOM, 2025-07-16) Costa, Thércio Henrique de Carvalho; Araújo, Anthunes Íkaro de; Nascimento, Igor Oliveira; Feitor, Michelle Cequeira; Libório, Maxwell Santana; Linhares, Álvaro Albueno da Silva; Vieira, Pâmala Samara; Alves, Salete Martins; https://orcid.org/0000-0001-7429-4273; https://orcid.org/0000-0003-0458-2557; https://orcid.org/0000-0002-4850-9493; https://orcid.org/0009-0007-8181-7280; https://orcid.org/0000-0003-1579-8775; https://orcid.org/0009-0009-6365-2691; https://orcid.org/0009-0002-0627-0530; https://orcid.org/0000-0002-2659-4746This study investigates the influence of deposition temperature on the formation of diamond-Like carbon (DLC) films on AISI 4340 steel using the cathodic cylinder plasma deposition (CCyPD) technique. The films were deposited in an acetylene atmosphere at 350°C, 400°C, and 450°C, and the samples were characterized using Raman spectroscopy, X-ray diffraction (XRD), Vickers hardness testing, and friction coefficient measurements. The results indicate that increasing the deposition temperature significantly impacts the microstructure and tribological properties of the DLC films. At 450°C, the films exhibited higher hardness due to the increased concentration of sp3 carbon, which led to a denser and more rigid structure. However, a notable reduction in film thickness was observed, likely due to increased carbon deposition efficiency and structural densification. The film deposited at 400°C demonstrated the optimal balance between hardness and wear resistance. These findings highlight the critical role of temperature control in optimizing the mechanical and tribological properties of DLC films for various industrial applicationsArtigo A novel technology to deposition diamond-like carbon thin films: cathodic cylinder plasma deposition(JOM The Journal of The Minerals, Metals & Materials Society (TMS), 2025) Araújo, Anthunes Íkaro de; Nascimento, Igor Oliveira; Feitor, Michelle Cequeira; Libório, Maxwell Santana; Linhares, Álvaro Albueno da Silva; Vieira, Pâmela Samara; Alves, Salete Martins; Sousa, Rômulo Ribeiro Magalhães de; Lima, Cleânio da Luz; Sousa, Ediones Maciel de; Costa, Thercio Henrique de Carvalho; https://orcid.org/0009-0007-8181-7280; https://orcid.org/0000-0002-4850-9493; https://orcid.org/0000-0003-1579-8775; https://orcid.org/0009-0002-0627-0530; https://orcid.org/0000-0002-2659-4746; https://orcid.org/0000-0003-3958-7008This study investigates the influence of deposition temperature on the formation of diamond-Like carbon (DLC) films on AISI 4340 steel using the cathodic cylinder plasma deposition (CCyPD) technique. The films were deposited in an acetylene atmosphere at 350C, 400C, and 450C, and the samples were characterized using Raman spectroscopy, X-ray diffraction (XRD), Vickers hardness testing, and friction coefficient measurements. The results indicate that increasing the deposition temperature significantly impacts the microstructure and tribological properties of the DLC films. At 450C, the films exhibited higher hardness due to the increased concentration of sp3 carbon, which led to a denser and more rigid structure. However, a notable reduction in film thickness was observed, likely due to increased carbon deposition efficiency and structural densification. The film deposited at 400C demonstrated the optimal balance between hardness and wear resistance. These findings highlight the critical role of temperature control in optimizing the mechanical and tribological properties of DLC films for various industrial applicationsArtigo Corrosion resistance of SAE 5160 steel deposited by duplex simultaneous treatment with hastelloy cathodic cage(Lubricants, 2025-04-12) Costa, Thércio Hentique de Carvalho; Brito, Marcos Cristino de Sousa; Pereira, Juliermes Carvalho; Silva, Lauriene Gonçalves da Luz; Monção, Renan Matos; Sousa, Ediones Maciel de; Sampaio, Weslley Rick Viana; Nascimento, Igor Oliveira; Araújo, Anthunes Íkaro de; Feitor, Michelle Cequeira; Sousa, Rômulo Ribeiro Magalhães de; https://orcid.org/0000-0001-7429-4273; https://orcid.org/0000-0002-0524-5117; https://orcid.org/0009-0006-1406-6184; https://orcid.org/0000-0003-4893-9976; https://orcid.org/0000-0002-0721-6766; https://orcid.org/0000-0003-2062-6505; https://orcid.org/0000-0003-3268-0197; https://orcid.org/0000-0001-5174-1077; https://orcid.org/0000-0003-0458-2557; https://orcid.org/0000-0002-4850-9493SAE 5160 steel, classified as high-strength, low-alloy steel, is widely used in the automotive sector due to its excellent mechanical strength and ductility. However, its inherently low corrosion resistance limits its broader application. This study explores the application of the cathodic cage plasma deposition (CCPD) technique to enhance the corrosion resistance of SAE 5160 steel. The treatment was performed using a Hastelloy cathodic cage under two atmospheric conditions: hydrogen-rich (75%H2/25%N2) and nitrogen-rich (25%H2/75%N2). Comprehensive analyses revealed significant improvements in surface properties and corrosion resistance. The hydrogen-rich condition (H25N) facilitated the formation of Cr0.4Ni0.6 and CrN phases, associated with a nanocrystalline structure (37.6 nm) and a thicker coating (45.5 μm), resulting in polarization resistance over 290 times greater than that of untreated steel. Conversely, nitrogen-rich treatment (H75N) promoted the formation of Fe3N and Fe4N phases, achieving a dense but thinner layer (19.6 μm) with polarization resistance approximately 20 times higher than that of untreated steel. These findings underscore the effectiveness of CCPD as a versatile and scalable surface engineering technique capable of tailoring the properties of SAE 5160 steel for use in highly corrosive environments. This study highlights the critical role of optimizing gas compositions and treatment parameters, offering a foundation for advancing plasma-assisted technologies and alloying strategies. The results provide a valuable framework for developing next-generation corrosion-resistant materials, promoting the longevity and reliability of high-strength steels in demanding industrial applicationsDissertação Produção de filmes DLC via deposição por plasma com cilindros catódicos(Universidade Federal do Rio Grande do Norte, 2024-06-13) Araújo, Anthunes Íkaro de; Costa, Thercio Henrique de Carvalho; https://orcid.org/0000-0001-7429-4273; http://lattes.cnpq.br/3647710047561421; http://lattes.cnpq.br/1828899248242526; Libório, Maxwell Santana; https://orcid.org/0000-0003-1579-8775; http://lattes.cnpq.br/1840848773429843; Costa, Tharsia Cristiany de CarvalhoEste estudo consiste na deposição de filmes finos de carbono em forma de diamante (DLC) em aço AISI 4340 por tratamento termoquímico, utilizando a técnica de deposição por plasma com cilindros catódicos (CCyPD) em reator de plasma. Esta técnica consiste na utilização de uma gaiola suporte para os cilindros de pós compactados, desenvolvida como uma nova variação da técnica de deposição por gaiola catódica. O objetivo é produzir filmes de DLC através da técnica CCyPD com alta dureza e bom comportamento tribológico para aumentar a resistência e vida útil do aço AISI 4340. O cilindro catódico foi produzido com pó de grafite e compactado com carga de 2 toneladas em prensa hidráulica. Os tratamentos foram realizados utilizando diferentes proporções dos gases argônio (Ar) e acetileno (𝐶2𝐻2) por um período de 4 horas, em potencial flutuante, utilizando disco de alumina. As caracterizações dos filmes depositados foram estudadas por Difração de raios X (DRX) para determinar as fases, e Espectroscopia Raman para composição química do filme. Para quantificar a dureza superficial e coeficiente de atrito, foram realizados os ensaios de Microdureza Vickers e pino-sobre-disco. Após o ensaio pino-sobre-disco, foi utilizado um aparelho rugosímetro portátil para realização de ensaio de perfilação da trilha de desgaste. Os resultados apresentaram características adequados de filme DLC, como a presença das fases de carbono e diamante no DRX, as bandas D e G na espectroscopia Raman, alta dureza superficial e baixo coeficiente de atrito, contribuindo para o aumento da vida útil do aço AISI 4340.