The electrical conductivity data of ceramic material at high temperatures can be useful in the application of modeling, solid oxide fuel cell (SOFC), and magnetohydrodynamic (MHD). The existing data is considerably lacking at extreme temperatures. Our research focuses on bridging this gap by reporting the electrical conductivity measurements of sets...
The role of A-site non-stoichiometry was investigated in lead-free piezoelectric ceramics based on compositions in the 1-x(Bi₀.₅Na₀.₅TiO₃)-xBaTiO₃ system near the morphotropic phase boundary where x = 0.055, 0.06 and 0.07. The samples were prepared by a conventional solid state mixed oxide route with the A- site stoichiometry modified to incorporate...
While the locomotion performance of legged robots over flat terrain or known obstacles has improved over the past few decades, they have yet to equal the performance of their animal counterparts over variable terrain. This work analyzes a multi-legged reduced order model of cockroach locomotion on variable slopes which will...
A new group of lead free piezoelectric perovskite solid solutions, (1-x)Bi(B'B")O₃-xABO₃, were obtained via solid-state processing techniques. The solubility of unstable perovskite Bi(B'B")O₃ compounds into stable perovskite compounds was found to be related to the tolerance factor of the ABO₃ perovskite endmembers. The morphotropic phase boundary (MBP) in perovskite solid...
The “why” of any situation is one of the most important questions to ask. Inventors have ideas every day. Some ideas are the brilliant ideas that lead to a better tomorrow. To protect these ideas, inventors turn to patents, a governmental grant of the right to stop others, for a...
Heavily acceptor doped Pb1.02Dx(Zr0.5Ti0.5)1-xO3 ceramics, where A is the dopant, were investigated in this research. Dopants studied included iron, magnesium and manganese at mole concentrations x ≤ 0.20. X-ray diffraction data along with scanning electron microscopy images revealed the solubility limits of these ceramics. All doped compositions exhibited a shift...
It has been well established that ferroelectric to relaxor crossover in piezoelectric ceramics exhibit promising electromechanical and dielectric properties over a wide temperature range, applying sensors and actuators transducers and such. A plethora of research has reported giant strain in various lead-free piezoelectric ceramics and attributed the reasoning to the...
This dissertation demonstrated that the electrical properties of complex oxide-based perovskite materials could be controlled through the careful modification of both material composition and structure. This was first shown through the modification of lead zirconate titanate (Pb(Zr0.52Ti0.48)O3, PZT) solid solutions with bismuth indate (BiInO3, BI) where the relative stability of...
This thesis examines the dielectric properties of two systems based on the perovskite materials
barium titanate and strontium titanate. A solid solution was created starting with these base
materials and then adding varying amounts of bismuth-zinc titanate and sodium niobate. These
compositions were calcined and sintered at temperatures determined to...
High energy density ceramic capacitors with temperature stable permittivity across -150°C to 300°C are desired for a wide variety of electronic devices. Traditional dielectrics such as barium titanate provide a high permittivity but that permittivity is strongly temperature dependent over this specified temperature range. The goal of this work is...