Study of Nickel as a Diffusion Barrier Between Uranium and Aluminum; ETUDE DU NICKEL COMME BARRIERE DE DIFFUSION ENTRE L'URANIUM ET L'ALUMINUM

The technological applicati on of U--Ni--Al ternary diffusion was studied for U-metal-base nuclear elements covered with a film of Ni (as an anti- diffusion barrier and as a metallic bond) and cladded with Al. The known surface treatments for Al and U and the deposition of Ni were improved. The behavior of Ni during the solid-state reactions wish U and Al at different temperatures and under various pressures was studied. By determining the composition of the various diffusion zones and establishing the diffusion laws, it is possible to calculate the thickness of the anti-diffusion barrier for the prescribed operating conditions (temperature, pressure and lifetime of a nuclear element). (auth)