Progress of Cryogenics and Isotopes Separation , ISSN: 1582-2575
2017, Volume 20, Issue 1

Durability studies of silicone elastomeric materials for gasket used in polymer electrolyte membrane fuel cell

Abstract

The durability of gaskets is an important issue for the performances and the operating lifetime of Polymer Electrolyte Membrane Fuel Cell (PEMFC). The role of gaskets is to prevent leakage of the reactive gases (hydrogen, oxygen) from the anode to the cathode (the reactants crossover) and the leakage of reactive gases and cooling agent outside the cell, too. Since assembling and throughout its operation, the gaskets are subjected to mechanical stress, by compression, to the chemical and electrochemical action of the environment, characterised by 100% relative humidity and variable temperature.

Three types of commercial room temperature vulcanize (RTV) silicone elastomers were subjected to a degradation test over 500 hours at temperatures of 60°C in a simulated environment of the fuel cell (acid medium containing F - ions). The monitoring of the material degradation was made by scanning electron microscopy (SEM), for surface cracks or pinpoint modification, atomic absorption spectrometry, for Ca²⁺ and Mg²⁺ ions release in test solution. Thermogravimetric analysis determined the thermal stability of not degraded and degraded samples. Indentation tests measure the samples hardness before and after durability test. It was found that the tested materials did not suffer significant degradation after 500 hours of testing in an environment like the one in the fuel cell.