Ultrafine amorphous Si/C/N ternary powders have been prepared in a CO2 laser assisted process. We demonstrate the possibility to drive the C/N ratio in the powder by properly choosing the experimental conditions and the gaseous reactant ratio in the initial mixture containing silane, dimethylamine, and ammonia. A kinetic model that accounts for reaching the equilibrium between the gaseous reaction intermediates and the solid products is proposed.

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Ultrafine, ternary (Si/C/N) ceramic powders have been produced after CO2 laser initiated reactions between silane and mono- or dimethylamine. Various spectroscopic diagnostics and chemical analyses, including ir spectrophotometry, x-ray photoelectron spectroscopy, and x-ray diffraction analysis have been employed to correlate the parameters involved in gas-phase reactions and the powder final composition.

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Important properties of the coating/substrate combination like hardness, stress and, in particular, adhesion rely partly on the morphology and microstructure of the interface, which is often physically and chemically different from the substrate as well as from the coating.The aim of this work is to study the influence of the chemical state of the metal surface on the structure of the interface AI2O,/Ti6A14V, obtained by deposition via sputtering of the ceramic.For this purpose three different surface treatments of the substrate were performed: air oxidation, cleaning by Ar+ sputtering and nitrogen ion implantation.The chemical composition of the treated surfaces was assessed by x-ray photoelectron spectroscopy, while the composition of the interfaces was investigated by Auger electron spectroscopy depth profiling.