Journal of Advanced Dielectrics,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Nov. 29, 2024
Solid
solutions
(SS)
with
a
quasi-binary
cross-section
of
four-component
system
the
composition
[Formula:
see
text](Na[Formula:
text]K[Formula:
text])NbO
3
–xPb(Ti[Formula:
text]Zr[Formula:
text])O
,
based
on
compositions
fundamentally
different
physical
responses
(Na,
K)NbO
(KNN),
Pb(Ti,
Zr)O
(PZT),
have
been
prepared
by
two-stage
solid-phase
synthesis
followed
sintering
using
conventional
ceramic
technology.
The
influence
thermal
cycling
dielectric
properties
SS
text]
has
studied.
It
shown
that
thermally
induced
fatigue
does
not
significant
effect
Curie
temperature
and
diffusing
phase
transition
(PT)
containing
only
extreme
components.
found
when
concentration
PZT
in
studied
is
varied,
text]/[Formula:
dependencies
take
form
characteristic
ferroelectrics
diffuse
PT.
When
repolarisation
cycles
are
parameter
Burns
temperatures
show
wave-like
behavior.
observed
effects
explained
interaction
defect
types.
A
conclusion
drawn
possible
practical
applications
SS.
Applied Physics Reviews,
Journal Year:
2024,
Volume and Issue:
11(3)
Published: Sept. 1, 2024
The
progress
of
next-generation
electromechanical
devices
is
substantially
reliant
upon
achieving
high
coupling
performance
in
piezoelectric
materials.
Here,
a
local
stress
regulation
strategy
introduced
to
significantly
enhance
the
overall
response
lead-free
piezoceramics.
A
remarkable
large
coefficient
(d33)
∼800
pC
N−1
and
longitudinal
factor
(k33)
88%
are
obtained
(K,Na)NbO3
(KNN)-based
textured
From
both
experimental
examinations
theoretical
simulation,
including
phase-field
analyses,
it
found
that
improved
primarily
stems
from
stress-induced
elastic
field
aligned
with
preferred
crystallographic
orientation,
which
constrains
domain
size,
resulting
nanoscale
short-range
ordered
structures.
Such
structures
facilitate
flexible
rotation
electric
dipoles
within
coexisting
phases
due
flattened
free
energy
distribution,
thereby
leading
exceptionally
response.
This
understanding
provides
valuable
guidance
for
design
novel
piezoceramics
excellent
performance.
Journal of Materials Chemistry C,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 1, 2025
Novel
approach
involving
multiple
formula
solid-solution
techniques
is
presented,
whereby
the
longstanding
conflict
between
d
33
and
T
C
in
KNN-based
ceramics
can
be
effectively
overcome,
thus
achieving
a
remarkable
of
550
pC
N
−1
260
°C.
To
advance
the
development
of
potassium
sodium
niobate
(KNN)-based
materials,
devices,
and
their
associated
applications,
this
study
introduces
a
collaborative
approach
to
optimization
materials
devices
for
wide-temperature,
high-resolution
nondestructive
testing
(NDT)
imaging.
This
is
achieved
through
integration
graded
lead-free
KNN-based
ceramics
wide-temperature-focused
ultrasonic
transducers.
The
KNN
ceramics,
featuring
coexistence
orthorhombic-tetragonal,
rhombohedral-orthorhombic-tetragonal,
rhombohedral-tetragonal
(O-T/R-O-T/R-T)
crystalline
phases,
were
engineered
enhance
both
thermal
stability
piezoelectric
performance.
in-situ
deviation
constant
remains
below
3.5%
at
140
°C.
Ultrasonic
transducers
capable
operating
across
wide
temperature
range
designed
fabricated
by
using
these
ceramics.
demonstrated
robust
imaging
performance
within
30
120
C-scan
images
obtained
spectrum
further
illustrated
potential
NDT
applications
in
diverse
environments.
marks
significant
breakthrough
field
wide-temperature
transducers,
as
it
indicates
first
successful
demonstration
capabilities
temperatures
exceeding
100
Lead-free
piezoelectric
materials
with
excellent
electromechanical
compatibility
are
essential
for
industrial
applications.
However,
attaining
both
a
large
coefficient
(d33)
and
high
mechanical
quality
factor
(Qm)
is
generally
regarded
as
challenging
because
of
the
inherent
trade-off
among
these
properties.
In
this
work,
reduction
internal
defects
redistribution
second
phase
in
potassium
sodium
niobate
(KNN)
based
composite
ceramics
achieved
through
heat
treatment
technique.
This
method
can
achieve
significant
improvement
properties
(d33
=
415
pC/N
Qm
120),
which
effectively
overcomes
contradiction
between
losses.
Structural
characterizations
indicated
that
improved
performance
annealed
KNN
could
be
attributed
to
optimized
extrinsic
local
stress
field.
These
findings
offer
promising
route
enhance
commercial
feasibility
lead-free
KNN-based
ceramics,
representing
progress
development
high-performance
environmentally
friendly
materials.
