Tape Cast Manufacturing

Piezoelectric
Tape Cast
Materials
Tape cast processing of
polycrystalline materials is widely
used for the production of single
or multilayered piezoelectric
materials. These materials are ideal
for micro-actuator applications.
CTS Corporation offers this
production capability in addition
to press processing to meet the
diverse needs of our customers.
Tape Cast Processing for
Multilayered Piezoelectric
Actuators
» Any shape of multilayered piezoelectric actuator can be
manufactured. Surfaces can be encapsulated for cleanliness or
insulation.
» Individual layers of the actuator are equipped with electrodes and
laminated. As with standard actuators, the ceramic is sintered to the
inner electrodes using a co-firing process.
» The more fine-grained the ceramic material used, the thinner the
layers that can be produced. The thickness of the active layers can
be as small as 20 to 30 μm for bender actuators.
» For high-dynamics applications, multilayered actuators are equipped
with electrodes for high currents. Combined with a high-power
piezo amplifier, high operating frequencies in the kHz range can be
attained. The rise times for nominal displacement are a few tens of
microseconds.
» The multilayer technology is a particularly innovative manufacturing
process. The first step is to cast tapes of piezoceramic materials
which are then provided with electrodes while still in the green state.
Many single tapes are laminated together to give a piezo element,
which is then sintered together with contact electrodes in a single
process step.
» The design comprises an all-ceramic outer layer of the actuator,
which acts as insulation. Any further coatings, made of polymer
materials for example, are therefore not required. This increases the
lifetime and reliability of the component.
The Tape Casting Process
Step 1 — Slurry Preparation and Tape Casting
• Piezoelectric material formulations for lower sintering
temperatures
• Tape thickness as low as 10 µm
Step 2 — Screen Printing, Stacking and Pressing
• Ag-Pd or Pt inner electrodes available
• Up to several hundred layers
• Laminating by isostatic pressing
Step 3 — Cutting and Green Shaping
• Automated cutting
• Flexible contours by milling, drilling or punching
Step 4 — Binder Burnout and Sintering
• Slow binder burnout up to 500 °C
• Co-firing temperatures ranging from 1100 °C to
1300 °C, depending on material
Step 5 — Layer Interconnection
• Via holes
• Termination screen printing or sputtering
• Soldering of the contact strip
Step 6 — Poling, Assembly and Final Inspection
• Poling at room temperature
• Assembly according to customer requirements
External Electrodes
Tape Cast Material at
Desired Thickness
Doctor
Blade
Tape
Casting
Internal Electrodes
Ceramic Layer
Multilayer Tape Cast Design
The Tape Cast Production Process
Slip
PZT 5A & 5H Materials (Soft PZT)
Property
Dielectric Constant (1kHz)
Dielectric Loss Factor (1kHz)
Symbol
K
Units
Material Type
T
3
tanδe
Dielectric Constant (1kHz)
K
Clamped Dielectric Constant
KS3
T
1
3195STD
3203STD
1800
3250
0.02
0.02
1500
2800
875
775
Density
ρ
g/cm3
7.7
7.7
Curie Point
Tc
ºC
350
225
Mechanical Quality Factor
Qm
80
50
Coercive Field
(Measured < 1 Hz)
Ec
kV/cm
14.9
10.6
Remanent Polarization
Pr
μCoul/cm2
39.2
37.2
kp
0.63
0.69
k33
0.70
0.70
k31
0.35
0.41
kt
0.49
0.56
k15
0.56
0.72
-175
-270
350
530
360
790
-11.0
-9.4
24.2
18.4
27.1
31.9
Coupling Coefficients
Piezoelectric Charge
(Displacement Coefficient)
d31
d33
Coul/N x 10-12 (or)
m/V x 10-12
d15
Piezoelectric Voltage Coefficient
(Voltage Coefficient)
g31
g33
V·m/N x 10
-3
g15
Frequency Constants Radial
Nr
Hz·m
2020
1920
Resonant Thickness
Ntr
Hz·m
2025
1870
Anti-Resonant Thickness
Nta
Hz·m
2250
2220
N31
Hz·m
1420
1400
υ
0.32
0.34
SE11
15.6
16.7
18.6
19.7
-5.3
-5.6
13
-6.8
-7.6
SE55
37.0
48.5
13.7
13.9
9.4
10.0
25.4
23.4
6.4
5.9
5.4
5.1
7.3
7.2
10.6
10.0
Poisson’s Ratio
S
Elastic Constants
Short Circuit
E
33
S
E
S
x 10 m /N
-12
12
2
E
S
D
Elastic Constants
Open Circuit
S
S
Elastic Constants
Short Circuit
Elastic Constants
Open Circuit
11
D
10 m /N
-12
33
2
D
55
YE11
Y
E
Y
Y
x 1010N/m2
33
D
11
D
33
x 1010 N/m2
Piezoelectric Tape Cast Production
Contact Sales
T: +1 (505) 348-4327
or +1 (505) 348-4616
[email protected]
www.ctscorp.com
2016.04 - NCH