The invention concerns an alveolar structure (1) comprising at least one
alveolar zone (2a, 2b) partially delimited by an associated leak tight
surface (4a, 4b) . According to the invention, each alveolar zone (2a,
2b) is formed of a plurality of metallic layers (8) superimposed parallel
to the associated leak tight surface (4a, 4b), each metallic layer (8)
comprising a network of passages (10) opening out on either side of said
metallic layer (8).The invention further concerns a method for
manufacturing said alveolar structure (1)Application to fuel cells and
heat exchangers.