High Performance Relaxor-based Piezoelectric Single Crystals
Abstract
High Performance Relaxor-based Piezoelectric Single Crystals. The investigation of high performance piezoelectric single crystals for application in advanced underwater projectors, sensors and receivers is proposed. The main objective of the proposed program is to identify new Relaxor-Pt compositions with Trts & Tcs significantly higher than current PMN-PT crystals, further enabling their acceptance in various applications, supplanting PZT polycrystalline ceramics. Common to all Relaxor -Pt crystals (non-tetragonal) are longitudinal coupling coefficients (K33s>90%), d33s > 1600 pC/N, and moderate mechanical Qs (~200). Two key parameters have been identified, specifically, the ferroelectric transitions, Trt ? 160°C and/or Tc ? 225°C, which would greatly allow expanded temperature usage, less temperature variability, and higher coercive fields (Ecs), all without sacrificing coupling and piezoelectric activity. In this work, the search for high Trt and Tc Relaxor Pt compositions will utilize established crystallographic perovskite tolerance factor relationships to help project novel ternary Pb(B1B2)O3- Pb( Mg,Nb)O3-PT systems. This approach will allow rapid screening of morphotropic phase boundary ( MPB) compositions with the requisite transition temperatures in the polycrystalline form. Assessment of crystal growth by melt processes, including Bridgman and/or flux Bridgman, will utilize various thermal analyses (e.g. dta and calorimetry) to determine melt and crystallization processes critical for crystal growth without excessive compositional segregation. In addition to achieving higher temperature transitions, novel resonant modes, e.g. d24, and d36, alternative crystallographic domain engineered orientations, such as 110 poled crystals, and the ability for acceptor doping (Generation III) to further enhance Mechanical Q can be readily applied, further expanding the application realm of piezo crystals.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 23, 2016
- Source ID
- N000141612952
Entities
People
- Thomas Shrout
Organizations
- Office of Naval Research
- Pennsylvania State University
- United States Navy