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.

RESUMO A nitretação a plasma é realizada em ferramentas de aços rápidos para aumentar a resistência ao desgaste da aresta de corte e reduzir a tendência do material usinado em aderir na ferramenta. O objetivo do presente trabalho é estudar a viabilidade da nitretação a plasma e do tratamento duplex em brocas de aço rápidoanalisnado o desgaste de brocas de aço rápido M2 submetidas a diferentes parâmetros de nitretação a plasma e deposição de filme de nitreto de titânio (TiN). As brocas passaram primeiro pelo tratamento de nitretação com, variando-se a temperatura em 350°C, 400°C, 450°C, 500oC e 550oC, enquanto o tratamento duplex foi dividido em nitretação convencional a 500 °C seguido de deposição de um filme fino de TiN aplicado pela técnica de deposição a plasma com gaiola catódica à temperatura de 400oC e 500 °C. As brocas nitretadas a 400°C ainda foram submetidas ao processo de deposição de um filme de TiN. Todas as brocas foram caracterizadas por microdureza Vickers e foram ensaiadas em centro de usinagem CNC, onde o corpo de prova era de aço AISI 4340. Foi realizada uma análise de desempenho entre os diferentes tratamentos, onde chegou à conclusão que o tratamento que resultou melhor desempenho na usinagem foi o tratamento de nitretação a 450°C. A camada nitretada das brocas foi analisada por perfil de microdureza, Microscopia Eletrônica de Varredura, porém observou-se que o valor de microdureza aumenta com o tempo de tratamento, e que a deposição do filme de TiN teve baixa relevância no desempenho da broca.

ABSTRACT The increase in tool life corroborates to the growth of productivity in manufacturing industries. In this context, the application of surface coatings is an alternative to increase the tool life of helical drills, especially those of small diameter. This paper studies the viability of plasma nitriding and duplex treatment on high speed steel drills. The studied nitriding treatments were performed at temperatures of 450 °C and 500 °C, while the duplex treatment was divided into conventional nitriding at 500 °C followed by the deposition of a TiN thin film applied by the cathodic cage plasma deposition technique at a temperature of 500 °C. The drills were characterized by Vickers Microhardness Test, Scanning Electron Microscopy (SEM), Energy Dispersion Spectroscopy (EDS) and Performance Simulation, where the flank wear on the cutting edge and the dimensional quality of holes machined in SAE 1045 steel specimens were measured. All treatments resulted in a higher surface hardness than that of untreated material. The tools subjected to nitriding and duplex treatment at 500 ºC presented underperformance, not showing viability for application under these conditions. The nitrided drill at 450 °C showed a longer tool life than the untreated drill and produced all holes within the limits set by the 9H12 tolerance. The study showed that the application of plasma nitriding at a temperature of 450 °C contributed to increase the tool life of high speed steel drills and to improve the dimensional quality of the holes.

Dielectric Barrier Discharge (DBD) is a promising technique for producing plasma in atmospheric pressure and is gaining emphasis in several areas, especially in the biomedical and textile industries, among other. This is due to the fact that this plasma does not reach high temperatures, enabling its use on thermally sensitive materials. However, there is still the need for the development of research relating to the field of physical mechanisms of non-thermal plasma. In this work, we studied the behavior of plasma in DBD equipment, varying distance between electrodes. For this study, two distinct characterization techniques were used. The first, the Lissajous Figures method, is effective and precise in the electrical characterization of DBD equipment. The second technique used, Optical Emission Spectroscopy (OES) is an effective tool in the diagnosis of plasma. This tool enables the identification of excited species in plasma. With the data produced, it was possible to identify an appropriate distance for producing plasma with a higher intensity and homogeneity of active species.

AbstractPolyester fabric samples – PET (poly (ethylene terephtalate)), were treated with oxygen plasma, in order to alter the hydrophilicity of such material. The process parameters: working pressure, current, tension and temperature were kept constant, varying only the treatment time. In order to evaluate the change caused on samples hydrophilicity, as well as the influence of the treatment time, the vertical wicking test was used. The samples were stored at standard temperature and pressure conditions, and their wettability were measured one day after the treatment and repeated after 30, 60 and 360 days, in order to check the stability of the effects produced. Scanning electron microscopy (SEM), Raman and ATR (Attenuated total reflection) spectroscopies were used to evaluate physical and chemical alterations on the samples surface. The results have shown a substantial improvement on the hydrophilicity of the treated samples compared to the non-treated sample.

Thin nitride and titanium dioxide films were produced using an innovative technique called cathodic cage depositon. Uniformity, three-dimensionality and high rate deposition are some of the advantages of this technique. In this study we discuss the influences of temperature, treatment time and gaseous atmosphere on the characteristics of the deposited films. The TiN (titanium nitride) and TiO2 (titanium dioxide) films were produced using a high deposition rate of 2,5 µm/h at a work temperature and pressure of 400°C and 150 Pa respectively. EDS technique was used to identify the chemical composition of the thin film deposited, whilst Raman spectroscopy indicated the phases present confirmed by DRX analysis. The thickness of the deposited films was studied using electron microscopy scanning. The results based on the deposition parameters confirm the great efficiency and versatility of this technique, which allows a uniform three-dimensional film deposition on any material without the appearance of stress. Compared to other techniques, cathodic cage deposition enables deposition at lower temperatures and higher pressures.