(US4522895-A)      Fuel cell carbonaceous electrode substrate includes a dense layer of average bulk density not less than 1.0 g/cc and a specific gas permeability of not more than 0.2 ml/cm. hr mm Aq. There is also a porous layer of uniformly porous carbonaceous material of average bulk density 0.3-1.0 g/cc and a specific gas permeability of not less than 20 ml/cm. hr mm Aq.    The dense layer in not more than half the thickness of the electrode substrate.    Holes extend between two parallel sides of the porous layer and parallel to the surface of the electrode substrate.    The holes are near the centre of the thickness direction of the porous layer and have a circular cross section.    The dense layer is pref. a graphite sheet.    ADVANTAGE -   There is a uniform distribution of temp. and contact resistance is low.    (11pp)    (US4666755-A)      Carbonaceuos electrode substrate for a fuel cell, comprises uniformly porous and carbonaceuos material. The electrode substrate has a first flat surface in contact with a separator sheet in a stack to form a fuel cell. A second flat surface is in contact with a catalyst layer and it has an average bulk density of 0.4 to 0.8 g/cm3 and a specific gas permeability of not less than 20 ml/cm.hr.mm Aq Not less than 60% of pores in the electrode substrate have a dia. of 10-100 microns, a numerous elongated holes for feeding reactant gases parallel to the flat surfaces of the electrode substrate and to each other extending from one side of the electrode substrate to an oppsite side, the holes are provided at the centre of the thickness of the electrode substrate which has a cross section of about 0.2-7 mm2. The holes are formed by interposing a polymer sheet material selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl alcohol and polyvinyl chloride as a raw material for forming holes between the raw materials for the electrode substrate, and calcium inan inert atmos.    (DE3335638-C)      New carbon-carrier material (I) for a fuel cell electrode comprises a dense layer and a porous layer of a permeable porous carbon material. The thickness of the electrode layer is not more than half the thickness of (I); a plurality of holes extend between two parallel sides of the porous layer and parallel to the surface of (I). The holes are situated in the vicinity of a plane which designates the middle of (I) and has a circular cross-section; the dense layer has a mean crude density of not less than 1.0 g per cubic cm and a specific gas permeability of not more than 0.02 ml/cm x hr. x Pa; and the hole diameter is 0.5-3.0 mm. The improvement is that the porous layer and the dense layer are integrated into one material; not less than 60% of the pores in the porous layer have a diameter of 10-100 microns; and the porous layer has a mean crude density of 0.4-0.8 g per cubic cm. and a specific gas permeability of not less than 2.0 ml/cm. x hr. x Pa.    ADVANTAGE -   Material (I) enables unrestricted charging of the gaseous reactants and has good mechanical strength and the operating behaviour of a fuel cell produced using material (I) is improved.    (16pp)