The effect of hydrogen partial pressure on uniaxial creep of 3Y-TZP/50 vol.% Pd cermet membranes

This study investigated the effect of hydrogen partial pressure ( p H 2 ) on the creep behavior of (3 mol% Y-TZP)/50 vol.% Pd cermet (YSZ/Pd), a hydrogen permeable material under development for separating hydrogen from mixed gases. Samples were subjected to uniaxial compression creep under both an inert (pure argon) atmosphere and p H 2 = 10 − 2   to   0.5   atm (balance Ar), in the temperature and stress ranges of 1150–1250 °C and 10–30 MPa, respectively. The creep measurements in Ar atmosphere yielded stress exponent and activation energy of n ≈ 2 and E = 582 kJ/mol, respectively, which is in good agreement with superplastic deformation of pure YSZ. The composite exhibits a tendency of decreasing n values with increase in p H 2 , reaching n ≈ 1.5 at p H 2 = 0.5   atm . The effect of hydrogen partial pressure on creep can be described by an exponent of r ≈ 1/6, resulting in an increase in creep rate by a factor of 2.5 upon switching from Ar to p H 2 = 0.5     atm .