Laser cladding of vanadium carbide powder developed an interlayer on AISI D6 steel as a diffusional barrier and to relief thermal residual stress. Laser cladding experiments varied resolution (DPI) and scanning speed (mm/s). CVD diamond deposition on this interface went on by HFCVD technique. The coatings were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM-FEG) and Raman spectroscopy. Ordered state V8C7 phase prevailed in the interlayer. The thickness of heat-affected zone (HAZ) and Laser Cladding Vanadium Coating (LCVC) were 37 µm and 5 µm, respectively, in the best layer produced. The diamond film showed good quality and morphology. The Raman peak at 1342,13 cm-1 shows the residual stresses level undertaken at the film-substrate interface and the corresponding adhesion, demonstrating the suitability of the VC laser cladding process to CVD diamond films deposition.

Filmes de nitreto de carbono, preparados por deposição assistida por feixe de íons, foram estudados pela espectroscopia de Raman e infravermelho, em função de energia de íons (200, 400, e 600 eV) e razão de chegada de íon a átomo R(I/A) de 0,9 a 2,5. A razão de composição N/C no filme, determinada por análise de detecção de recuo elástico, foi encontrada proporcional a R(I/A); porém, a formação de filme é possível somente se R(I/A) for menor do que um valor crítico da eficiência de "sputtering" químico. Esse valor encontrado foi de 0,21. O valor máximo de N/C obtido foi de 0,9 (47% atômica de nitrogênio) para o filme depositado com 400 eV. Para entender o efeito de incorporação de nitrogênio na estrutura dos filmes, os parâmetros foram determinados pela análise dos espectros Raman e encontrados fortes dependências da quantidade de nitrogênio nos filmes; os comportamentos da posição e da largura do pico G, e da razão I D/I G são correlacionados com as mudanças estruturais nos filmes.

Carbon nitride films prepared by ion beam assisted deposition were studied by Raman and infrared spectroscopy, as a function of nitrogen ion energy (200, 400, and 600 eV) and the ion to atom arrival rate ratio R(I/A) ranging from 0.9 to 2.5. The composition ratio N/C in the film determined by elastic recoil detection analysis was found to be proportional to R(I/A); however, the film growth is possible only if R(I/A) is smaller than a critical value of chemical sputtering yield. This value was found to be 0.21. The maximum value of N/C obtained was 0.9 (47 at.% of nitrogen) for the film deposited with ion energy of 400 eV. In order to understand the effect of nitrogen incorporation on the structure of the films, the parameters were determined from the Raman spectra analysis of the films and found to show strong dependences of the nitrogen content in the films; the behaviors of the G peak position and width, and I D/I G ratio are correlated with the structure changes in the films.

Adherent and low-stress a-C:H films were deposited on Ti6Al4V and stainless steel substrates using PECVD and IBAD techniques. An amorphous silicon interlayer was applied to improve the adhesion of the a-C:H films on the metal substrates. The XPS technique was employed to analyze the chemical bondings within the interfaces. The elemental composition and atomic density of the films were determined by ion beam analysis. The film microstructure was studied by means of Raman scattering spectroscopy. The mechanical properties were determined by means of stress and hardness measurements. The adherence was evaluated by means of scratch tests. The tests showed that the composition, the microstructure, and the mechanical properties of the films depend on the intensity of the ion bombardment and on the ion current.

The stress evolution in diamond films grown on Ti6Al4V was investigated in order to develop a comprehensive view of the residual stress formation. Residual stress is composed of intrinsic stress induced during diamond film growth and extrinsic stress caused by the different thermal expansion coefficients between the film and substrate. In the coalescence stage it has been observed that the residual stress is dominated by the microstructure, whereas on continuous films, the thermal stress is more important. In this work diamond thin films with small grain size and good size and good quality were obtained in a surface wave-guide microwave discharge, the Surfatron system, with a negative bias voltage applied between the plasma shell and substrate. For above of -100V applied bias, the ratio of carbon sp³/sp² bond may increase and the nucleation rate increase arising the high value at the -250V applied bias. Stress measurements and sp³ content in the film were studied by Raman scattering spectroscopy. The total residual stress is compressive and varied from -1.52 to -1.48 GPa between 0 and -200 V applied bias, respectively, and above the -200 V, the compressive residual stress increased drastically to -1.80 GPa. The diamond nucleation density was evaluated by top view SEM images.

In this work we study the influence of oxygen addition to several halocarbon-hydrogen gas systems. Diamond growth have been performed in a high power density MWCVD reactor built in our laboratory. The growth experiments are monitored by argon actinometry as a reference to plasma temperature and atomic hydrogen production, and by mass spectrometry to compare the exhaust gas composition. Atomic hydrogen actinometry revealed that the halogen presence in the gas phase is responsible for a considerable increase of atomic hydrogen concentration in the gas phase. Mass spectrometry shows similar results for all gas mixtures tested. Growth studies with oxygen addition to CF4/H2, CCl4/H2, CCl2F2/H2 and CH3Cl/H2 reveals that oxygen increases the carbon solubility in the gas phase but no better diamond growth conditions were found. Halogens are not, per se, eligible for diamond growth. All the possible advantages, as the higher production of atomic hydrogen, have been suppressed by the low carbon solubility in the gas phase, even when oxygen is added. The diamond growth with small amount of CF4 added to CH4/H2 mixture is not aggressive to the apparatus but brings several advantages to the process.

Boron doped diamond thin films were grown on titanium alloy substrates (Ti6Al4V) with 36 × 35 × 1.3 mm at 873-933 K at 6.5 × 10³ Pa during 8 h by hot filament CVD assisted technique. The boron source was obtained from a H2 line forced to pass through a bubbler containing B2O3 dissolved in methanol (B\C = 6000 ppm). The films were grown on both sides of perforated and non-perforated substrates. Emphasis for diamond growing on perforated substrates have been done in order to increase the active surface area and hereafter to promote an easier electrolyte flow for wastewater treatment. The electrode performance was determined by cyclic voltammetry measurements in KCl, KNO3, Na2SO4, HCl, HNO3 and H2SO4 solutions and the reversibility behavior of the Fe(CN)6(3-/4-) at the Ti6Al4V/Diamond electrode were studied. Also, Scaning Electron Microcopy and Raman Scattering Spectroscopy were used for morphology and diamond quality evaluation, respectively.