Accession Number:

ADA279718

Title:

Development of a High-Frequency Multilayer Copolymer Acoustic Projector

Descriptive Note:

Final rept.

Corporate Author:

NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI

Personal Author(s):

• Kavarnos, George J.
• McLaughlin, Elizabeth A.

Report Date:

1994-03-31

Pagination or Media Count:

30.0

Abstract:

This report describes the preparation of piezoelectric vinylidene fluoride-trifluoroethylene PVDF-TrFE copolymer films for a broadband, high- frequency projector, and the fabrication and acoustic testing of the projector. Raw PVDF-TrFE copolymer powder was dissolved in an organic solvent and cast into a shallow mold. After the solvent had evaporated, the -200 microns thick films were annealed and subsequently slow cooled. A goldpalladium metallic layer was sputtered onto both sides of the film for electrodes, and each film was conventionally poled in a hot oil bath. The capacitance of a single layer with an area of 6.45 cM2 1 in.2 was typically -200 pF. The electroded copolymer layers were bonded together with epoxy and wired in parallel. The piezoelectric constant d33 measured on a four-layer sample, using laser Doppler vibrometry, was -34 pCN. A seven-layer sample was waterproofed and the projector was evaluated acoustically. The transmitting voltage response at resonance 542 kHz was 156 dBmicrons Pa-mV, and the bandwidth was 240 kHz.

Descriptors:

• *COPOLYMERS
• *SONAR PROJECTORS
• ANNEALING
• HIGH FREQUENCY
• VOLTAGE
• ELECTRODES
• BROADBAND
• ACOUSTICS
• ORGANIC SOLVENTS
• FLUORIDES
• CAPACITANCE
• PALLADIUM
• THICK FILMS
• TRANSMITTING
• SPUTTERING
• UNDERWATER ACOUSTICS
• BANDWIDTH
• SOLVENTS
• RESONANCE
• LASERS
• POWDERS
• FABRICATION

Subject Categories:

• Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE