Physics For Civil Engineering: Unit IV: New Engineering Materials
Piezo and Ferroelectric Ceramics
Definition, Structure, Curie Temperature, Curie Constant, Hysteresis
We know that the piezoelectric crystals undergo a change in polarisation when they are subjected to a stress.
PIEZO AND FERROELECTRIC CERAMICS
We know that the piezoelectric crystals
undergo a change in polarisation when they are subjected to a stress. The
application of compressive stress results in the displacement of charge in one
direction while tensile stress leads to the displacement of charge in opposite
direction.
Pyroelectric
crystal is one which produces spontaneous polarisation due
to application of electric field. Further in these crystals, a change in
temperature also produces a change in spontaneous polarisation.
On the other hand, if one changes the
direction of electric field, the direction of spontaneous polarisation also
changes. The crystals exhibiting this additional property are known as
ferroelectrics.
Therefore, ferroelectric crystal exhibit
spontaneous and reversible polarisation. Most of the properties of
ferroelectricity and ferromagnetism are common.
The ferroelectric properties disappear
at certain temperature TC (curie temperature). The crystal will be
in paraelectric state above TC, which is analogous to paramagnetism.
The crystal in the paraelectric state
obeys Curie-Weiss law. Therefore, the spontaneous polarisation takes place,
below TC
Examples for the ferroelectric ceramics
are Rochelle salt, BaTiO3, SITO3 PbTiO3 LiNbO3,
NaNbO3, KNbO3, PbTa2O3, etc. The
structure, Curie temperature and Curie constants of ferroelectric ceramics are
shown in Table.
Table:
4.1
Structure,
Curie Temperature and Curie Constant of Ferroelectric Ceramics
Hysteresis
Ferroelectric ceramic materials exhibit
the hysteresis behaviour. The hysteresis behaviour exhibited by a single
crystal and polycrystalline material is shown in fig. 4.24 and fig. 4.25
respectively.
Physics For Civil Engineering: Unit IV: New Engineering Materials : Tag: : Definition, Structure, Curie Temperature, Curie Constant, Hysteresis - Piezo and Ferroelectric Ceramics
Physics For Civil Engineering: Unit IV: New Engineering Materials
Under Subject
Physics for Civil Engineering
PH3201 2021 Regulation | 2nd Semester Civil Dept 2021 Regulation
Related Subjects
Professional English II
HS3251 2nd Semester 2021 Regulation | 2nd Semester Common to all Dept 2021 Regulation
Statistics and Numerical Methods
MA3251 2nd Semester 2021 Regulation M2 Engineering Mathematics 2 | 2nd Semester Common to all Dept 2021 Regulation
Engineering Graphics
GE3251 eg 2nd semester | 2021 Regulation | 2nd Semester Common to all Dept 2021 Regulation
Physics for Electrical Engineering
PH3202 2nd Semester 2021 Regulation | 2nd Semester EEE Dept 2021 Regulation
Basic Civil and Mechanical Engineering
BE3255 2nd Semester 2021 Regulation | 2nd Semester EEE Dept 2021 Regulation
Electric Circuit Analysis
EE3251 2nd Semester 2021 Regulation | 2nd Semester EEE Dept 2021 Regulation
Physics for Electronics Engineering
PH3254 - Physics II - 2nd Semester - ECE Department - 2021 Regulation | 2nd Semester ECE Dept 2021 Regulation
Electrical and Instrumentation Engineering
BE3254 - 2nd Semester - ECE Dept - 2021 Regulation | 2nd Semester ECE Dept 2021 Regulation
Circuit Analysis
EC3251 - 2nd Semester - ECE Dept - 2021 Regulation | 2nd Semester ECE Dept 2021 Regulation
Materials Science
PH3251 2nd semester Mechanical Dept | 2021 Regulation | 2nd Semester Mechanical Dept 2021 Regulation
Basic Electrical and Electronics Engineering
BE3251 2nd semester Mechanical Dept | 2021 Regulation | 2nd Semester Mechanical Dept 2021 Regulation
Physics for Civil Engineering
PH3201 2021 Regulation | 2nd Semester Civil Dept 2021 Regulation
Basic Electrical, Electronics and Instrumentation Engineering
BE3252 2021 Regulation | 2nd Semester Civil Dept 2021 Regulation
Physics for Information Science
PH3256 2nd Semester CSE Dept | 2021 Regulation | 2nd Semester CSE Dept 2021 Regulation
Basic Electrical and Electronics Engineering
BE3251 2nd Semester CSE Dept 2021 | Regulation | 2nd Semester CSE Dept 2021 Regulation
Programming in C
CS3251 2nd Semester CSE Dept 2021 | Regulation | 2nd Semester CSE Dept 2021 Regulation