Functionally graded ferroelectric polyetherimide composites for high temperature sensing

High temperature ferroelectrics for thermally stable devices that can detect pressure and temperature are of great industrial interest. Here we describe composites of lead titanate (PT) particle-polyetherimide (PEI) polymers with stable dielectric and piezoelectric properties over a broad range of temperature and frequency. The reported...

Structure, dielectric and piezoelectric properties of donor doped PZT ceramics across the phase diagram

The effects of Zr/Ti ratio on the dielectric and piezoelectric properties of the sintered Pb(ZrxTi(1−x))0.99Nb0.01O3 piezoelectric ceramics across the entire range of phase diagram of the PZT solid solution was studied systematically. The materials were prepared by the conventional mixed oxide process. The phase purity and crystal structure of...

Piezoelectric and mechanical properties of structured PZT-epoxy composites

Structured lead zirconium titanate (PZT)-epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage on piezoelectric properties of the composites is...

Modeling and characterization of dielectrophoretically structured piezoelectric composites using piezoceramic particle inclusions with high aspect ratios

In this work, the piezoelectric properties at high electric fields of dielectrophoretically aligned PZT - polymer composites containing high aspect ratio particles (such as short fibers) are presented. Polarization and strain as a function of electric field are evaluated. The properties of the composites are compared to those of PZT-polymer...

A quick method to determine the capacitance characteristics of thin layer X5R multilayer capacitors

The effect of Y2O3 concentration on the dielectric properties of ceramic disc capacitors and multilayer capacitors containing 50 dielectric layers with an approximate thickness of 3µm were investigated. The relative permittivity and temperature coefficient of capacity of multilayer capacitors at low and high applied field suggest that two types...

Theoretical investigation of van der Waals forces between solid surfaces at nanoscales

A theoretical investigation of van der Waals forces acting between two solid silicon surfaces at separations from zero to approximately 20 nm is presented. We focused our efforts on the analysis of different factors that can cause deviations from the classical pressure-distance dependence p ∼ 1/D3. It is demonstrated that a layer (oxide or water...

Worldwide distribution of soil dielectric and thermal properties

Ground penetrating radar and thermal sensors hold much promise for the detection of non-metallic land mines. In previous work we have shown that the performance of ground penetrating radar strongly depends on field soil conditions such as texture, water content, and soil-water salinity since these soil parameters determine the dielectric soil...

Dielectric properties reflecting coating performance

The use of Electrochemical Impedance Spectroscopy (EIS) in coatings research is widespread. The information obtained by this technique is often limited, which is the result of too high expectations and inadequate analysis and interpretation. Analysis of the dielectric properties of organic coatings using a Constant Phase Element (CPE) in the...