Benjamin Renouf oral presentation (SN1-Mon1-3-2)
Diffusion in a multilayer W/WC/Hf on a porous W substrate
1 Laboratoire des Multimatériaux et Interfaces, 22 Avenue Gaston Berger, 69622 Villeurbanne, France
2 GEMAC, 45 avenue des Etats Unis, 78035 Versailles, France
3 Laboratoire Ampère, 43 boulevard du 11 novembre, 69622 Villeurbanne, France
The diffusion and the thermo-mechanical stability in high temperature of a multilayer deposit of refractory metals -W/WC/Hf- were investigated by secondary ion mass spectrometry (SIMS) analysis. The purpose of this study is to check the integrity of the hafnium surface layer after heat treatments. Two samples of multilayer system on porous tungsten substrate were manufactured. The multilayer pattern was deposit by a cleanroom lithographic and sputtering process. In order to detect diffusion, one of the two samples has been treated several times by a flash thermal anneal under vacuum from room temperature to 1000°C in few seconds. Next, the two samples were analyzed by SIMS with a Cameca IMS7f with a high-resolution mass. Mass spectrums for first assessments of all present elements were made, and, considering interferences, this step allows us to choose isotopes for the profile. The elements detected were all refractory metals and the intrinsic masses are consequently very close. A good mass resolution was therefore necessary. Then, five depth profiles were acquired for each sample. An O2+ analytical configuration was selected due to the objective which is to study the diffusion phenomena. For each sample, the most pertinent profile was chosen and finally the superposition of the two profiles allowed us to highlight a migration of the carbon isotope to the hafnium coating and diffusion between the three deposited layers. Despite the diffusion, we can conclude that the deposit layer in surface remains predominantly composed of hafnium.