(US4774154-A)      Phosphoric acid fuel cell has a housing contg. a fuel cell stack comprises of layered fuel cell plates having edges including adjacent anode and cathode plates having small gaps between them for contg. electrolyte soln. A seal between the edges of adjacent anode and cathode plates is formed using a seal material comprising (1) corrosion resistant, high temp. stable fluorinated hydrocarbon elastomer and (2) blowing agent which activates in the curing temp. range of (1) to produce fully cured closed cell elastomer. The seal material can also include blowing agent promotor, reinforcing filler and acid accepting material. Pref. (2) is azodicarbonamide.    ADVANTAGE -   The seal material is physically and chemically stable at the normal operating temp. of a fuel cell and is corrosion resistant to the electrolytic soln.    (5pp)    (JP2558707-B2)      Sealing material, specially for use in fuel cells, is a fluorocarbon rubber such as Fluorel or Viton (RTM) and a chemical blowing agent which is activated in the range of the curing temperature of the fluorocarbon. This agent is pref. an azodicarbonamide, such as Celogen AZ- 130 (RTM). A promoter is recommended for this agent, e.g., B-I-K (RTM), also a filler such as carbon black, Thermax MT (RTM), also an acid acceptor such as Maglite (RTM).    ADVANTAGE -   This sealing material is physically and chemically stable at the normal working temp. of a fuel cell of 204 deg. C and is corrosion resistant in the electrolyte soln. (often H3PU4).    (DE3719525-C2)      Sealing material, specially for use in fuel cells, is a fluorocarbon rubber such as Fluorel or Viton (RTM) and a chemical blowing agent which is activated in the range of the curing temperature of the fluorocarbon. This agent is pref. an azodicarbonamide, such as Celogen AZ- 130 (RTM). A promoter is recommended for this agent, e.g., B-I-K (RTM), also a filler such as carbon black, Thermax MT (RTM), also an acid acceptor such as Maglite (RTM).    ADVANTAGE -   This sealing material is physically and chemically stable at the normal working temp. of a fuel cell of 204 deg. C and is corrosion resistant in the electrolyte soln. (often H3PU4).