The compounds PuCu 2 and PuCu 4 are brought to evidence by solid state diffusion. The growth kinetics and the formation mechanism of these phases are studied using couples constituted of a biphased Pu-Cu alloy and of pure copper. A ternary phase of approximative composition PuCu 3 with a variable amount of Ga is brought to evidence using couples constituted of pure copper and of PuGa alloys. Crystalline parameters are determined by the Debye-Sherrer method on alloys obtained by direct elaboration or by diffusion.