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