Piezoelectric materials is a material that can can generate a Voltage
corresponding to mechanical stess change. Although it was discovered in
1880, it was not widely used until the 1950s. Over the past half decade,
PZT ceramics materials (PbZr1-xTixO3) have been studied and
demostrated by researchers and It has a relatively large piezoelectric
coefficient (d33 = 220 ÷ 590 pC / N). That‟s why most piezoelectric
applications, both telephone batteries and high-tech scanning-tunneling
microscopes use PZT piezoelectric materials.However, Pb is a radioactive
element. It not only is very dangerous to humans but also it is one of the
causes of global environmental pollution if used extensively. Therefore, it
is imperative for scientists to find out that piezoelectric materials not
contain Pb with a high piezoelectric coefficient which can be use instead of
traditional PZT materials. Some piezoelectric materials not contain Pb
have recently been publish and have shown good results. Special, material
systems not contain Pb on (K,Na)NbO3 and BaTiO3 substated.
However, in our understanding, piezoelectric material systems not contain
Pb have not been adequately researched. There are some publications
published in international journals, but a few and sporadically. The
physical mechanism to explain the cause of the high piezoelectric
coefficient and the properties of the material is still a lot of unsoud, need to
focus more research, deeper.
In the country, piezoelectric material systems are studied by many
scientists in centers, scientific institutes and universities such as Ha Noi
unviersity of Science and Technology, University of Science-Hue
University . In order to promote the research activities on the family of
piezoelectric materials not contain Pb and based on the actual situation as
well as research conditions such as experimental equipment, references,
research collaboration capabilities with domestic research team . We think
that studying and solving the problems mentioned above is useful and will
give many positive results. Especially finding the relationship between the
big piezoelectric coefficient and the dielectric recovery time of the object
piezoelectric. This is why we choose this thesis “Fabrication of
ferroelectric materials do not contain Pb on BaTiO3 substrate and study
their electricity and piezoelectricity properties”. we believe that our work
will be sussces and will be useful for the understand about the interaction
electric mechanism in the ferroelectric material systems, piezoelectric not
contain Pb, also open application capacibility of these material systems in
fabrication of pin, senso contributory on the environment reduction.The main contents of my thesis is present in 4 chapters:
Chapter 1. Theoritical overview
Chapter 2. Experiment
Chapter 3. Effected of Ca substitution for Ba on the structure and
magnetic properties of BCT and BZT-BCT
Chapter 4.The relationship between time of restore dielectric and
piezoelectric properties of BCT and BZT-BCT