We investigate the structural, optical, thermal-optical, and electronic properties of TiNx thin films utilizing a variety of experimental techniques, including spectroscopic ellipsometry, Raman spectroscopy, scanning electron microscopy, atomic force microscopy, thermal lens spectroscopy, and UV-VIS spectroscopy. Our experimental results indicate a remarkable metallic character in the TiNx thin films deposited under lower N2 flow during treatment, as well as an increase in reflectance in the infrared region and thermal diffusivity as the partial N2 flow is reduced, which is consistent with previous experimental studies. The microscopic origin of these trends is explained in terms of the atomic structure of the system, where Ti atoms contribute free carriers that interact with IR radiation and N atoms create imperfections in the lattice, causing greater scattering of phonons, respectively. The experimental results also indicate that the roughness of the films produced with a lower N2 partial flow was lower than that of the films with a higher N2 partial flow. To explain the deviation of optical properties from the ideal case, surface oxidation is also investigated. This facilitates the coating of smarting windows with TiNx thin films. structural thermaloptical, thermaloptical thermal-optical techniques ellipsometry spectroscopy microscopy UVVIS UV VIS treatment reduced studies system lattice phonons respectively case investigated

Molybdenum trioxide (MoO3) thin films are generally deposit on metallic surfaces to increase their tribological performance. In this manuscript, MoOx coatings were for the first time deposited on plasma nitrided surfaces. Vickers microhardness tests, X-ray diffractometry, and micro abrasive wear tests characterized the samples. It was investigated the effect of temperature in hardness and tribological properties of austenitic stainless steel surfaces. When the temperature of plasma nitriding increases, the coating thickness and the nitrogen diffusion on the treated surface also increases, favoring the hardness of the coatings. After MoOx deposition, the predominant MoO3 phase with monoclinic and orthorhombic unit cells was observed. MoOx coatings after plasma nitriding demonstrated the highest wear resistance.

Abstract AISI D6 tool steel and AISI 304 stainless steel are among the most widely used material in the industry. However, this application field can still be expanded through the coatings deposition. In this regard, the objective of this work was to evaluate the impact of coatings application by cathodic cage technique using Hastelloy’s cathodic cage, on corrosion resistance of these steels. Two treatment temperatures were compared. The samples were characterized by Optical Microscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction with the application of the Rietveld routine and corrosion test. The results showed the formation of multiphase layers that contributed to corrosion potentials reduction for treatments at 400 °C, being more effective when applied on AISI D6. It was observed that the corrosion resistance is influenced by the temperature, which was attributed to the precipitation of chromium nitride and iron oxide at 450 ºC.

RESUMO A crescente necessidade de aumentar a produtividade do setor industrial, impulsiona o desenvolvimento de novos aços e novos tratamentos que possam melhorar o desempenho e a vida útil de ferramentas de corte, conformação e estampagem. Tratamentos de superfície assistidos por plasma destacam-se nesse contexto. Trabalhos anteriores têm demonstrado que esses revestimentos são eficientes no aumento da dureza, na resistência ao desgaste e na resistência a corrosão de diversos tipos de aços. Nesse sentido, amostras e ferramentas de aços AISI M2 e D2 termicamente tratadas foram submetidas aos processos de nitretação a plasma convencional, em gaiola catódica e tratamento duplex com o objetivo de avaliar o efeito desses tratamentos em ferramentas de conformação buscando a viabilidade da aplicação do método no setor industrial com a redução do custo de fabricação na conformação e estampagem de pregos. Ensaios de microdureza Vickers, análise por MEV e Difração de Raios-X (DRX) possibilitaram identificar propriedades mecânicas, camada de compostos e as fases presentes, respectivamente. O desempenho das ferramentas baseou-se na quantidade de pregos produzida em kg. O custo produtivo foi determinado em função da produtividade, do preço de aquisição da ferramenta e do preço da nitretação. O uso da nitretação a plasma se mostrou viável para os dois aços, destacando-se o fato de que as ferramentas de aço D2 nitretadas a 480ºC por 3 horas, obtiveram os maiores ganhos de produtividade em relação a ferramenta não nitretada. A aplicação da nitretação convencional na ferramenta de aço M2 a 480ºC por 4 horas possibilitou a redução de seu custo em 26% e redução de 3,5% sobre o custo total de produção de pregos, obtendo o melhor custo-benefício.

ABSTRACT The growing need to increase the productivity of the industrial sector, drives the development of new steels and new treatments that can improve the performance and useful life of cutting, forming and stamping tools. Plasma-assisted surface treatments stand out in this context. Previous research has shown that these coatings are efficient in increasing hardness, wear resistance and corrosion resistance of different types of steels. In this sense, samples and tools from AISI M2 and D2 heat-treated steels were subjected to conventional plasma nitriding processes, in cathodic cage and duplex treatment in order to evaluate the effect of these treatments on forming tools seeking the viability of applying the method in the industrial sector with the reduction of the manufacturing cost in the conformation and stamping of nails. Vickers microhardness tests, SEM analysis and X-Ray Diffraction (XRD) made it possible to identify mechanical properties, layer of compounds and the phases present, respectively. The performance of the tools was based on the volume of nails produced in kg. The productive cost was determined in function of productivity, the purchase price of the tool and the nitriding price. The use of plasma nitriding proved to be feasible for both steels, highlighting the fact that the D2 steel tools nitrided at 480ºC for 3 hours, obtained the greatest productivity gains in relation to non-nitrided tool. The application of conventional nitriding in the steel tool M2 at 480ºC for 4 hours made it possible to reduce its cost by 26% and reduce by 3.5% the total cost of producing nails, obtaining the best cost-benefit ratio.