Abstract
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
.