Microwave processing of dielectric ceramics and effect of nanoparticles as sintering aids

International Conference and Expo on Ceramics

August 17-18, 2015 Chicago, USA

K C James Raju

Posters-Accepted Abstracts: J Material Sci Eng

Abstract :

Densification of electronic ceramics with minimum porosity is an important requirement for applications involving
dielectrics, ferroelectrics and piezoelectrics. Often properties depend on the grain size itself while the porosity would
degrade the quality of the ceramics. Achieving good density at lower temperatures and in short duration is the challenge. The
methods that are found to solve these problems include usage of nanoparticles of the material as its own sintering and using
microwave power either at the calcination stage or sintering stage or both. In many cases, atleast in one stage conventional
processing has given better results. How the microwave processing results in different microstructures, faster sintering process
and evolution of newer material phases is interesting. The way the microwave furnaces can be used for such purposes in
different modes is also an important aspect. The electromagnetic field configuration inside the furnace chamber, role of
additional structures that are to be used inside the microwave furnace like susceptor and insulations also need to be taken
into account. The presentation would cover these topics including a tutorial on microwave processing and the phenomena
involved. The material systems covered includes ferroelectric BaTiO3, thermoelectric SrTiO3, high temperature piezoelectric
SrBi4Ti4O15, low loss dielectrics like (Zr,Sn)TiO4 and Ba (Zn1/3 Ta2/3)O3. In some cases new types of ordering were discovered in
these materials by microwave processing. But the fast processing given by microwave method gives its own problems when it
comes to ordering and grain growth and they will be discussed. Usage of nanoparticles of the same materials as sintering aid is
another topic that will be introduced.

Biography :

K C James Raju did his PhD in microwave materials and measurement techniques from Indian Institute of Technology, Chennai in 1996 and joined University
of Hyderabad. His work is on low loss microwave materials, ferroelectrics, high temperature piezoelectrics and microwave processing of materials. For various
device developments, he make these materials as thin film films for which he uses techniques like sol-gel processing, RF sputtering, pulsed laser deposition and
laser annealing. He works on developing characterization techniques for materials and thin films in the microwave frequency range. Using simulation software’s,
he studies the microwave test structures. For bulk material processing, he uses microwave assisted processing with good success even for low loss materials and
found interesting results. The usage of nano particles of a particular material as sintering aid for sintering of the same composition is another area of his interest.
He currently works on ways to reducing the processing temperatures of materials and thin films.