Studies of surface physics for coating nuclear materials with hard thin films by plasma processing

This work has as goals obtaining preliminary information necessary for developing plasma technique for coating with hard films, obtaining thin films with special properties and developing experimental methods for characterization of these films. Special properties (high hardness, corrosion resistance, high thermal conductivity, in case of nitrides and diamond like films), leading to a large variety of applications, the nuclear field including, are controlled by the microstructure and microchemistry of these films. Characterization of the deposition by plasma technique of hard films assumes the characterization of the coatings as well as understanding of the relationship between the microchemistry and their microstructure. A study of the chemical bonds in the analysed deposition are presented. Experimental determinations were conducted for the following types of depositions: - the BCN type deposition performed with pulsed laser ablation; - deposition of CN type obtained in RF plasma jet; - deposition of CN type obtained by laser induced chemical vapor deposition. The XPS analysis evidenced chemical bonds between BC and N. In case of CN film deposition two nitride phases were found. From 'chemical shift' in the electron spectra identification of the different chemical bond types was possible as well as their different weights. It was found also that beside other parameters characterizing the deposition processes, the nature of the substrate is affecting much the composition of the deposit film