PREFCICE
CORDIERITE, 2 M g 0 2 A l 2 O 3 5 S i Q 2
1s
an important member
the ternary system Mg0-41203-Si02
by
low
thermal
resistance
expansron,
and
It
is
excellent
in
characterized
thermal
low d i e l e c t r i c constant
view
of
these properties it is widely used as kiln furniture
In
whiteware
industry
packaging
industry
monoliths
coated
well
as
as
in
It LS a l s o
micro
used
with c a t a l y s t s t o
In
shock
as
combat
electronic
honeycomb
automotive
exhaust emissions t o reduce pollution
As
Cordierite
is
used in large
quantities,
there
considerable interest in improving p r o p e r t i e s using
Hence, an attempt h a s been made in
raw materials
study
to
materials
properties
synthesise
from
cardierite
Indlan
Also
from
sources
and
f o r the first time,
is
available abundantly and
is
raw
study
their
Cordierite
an environmental
new
t h ~ s
various
been synthesised from an industrial waste Flyash,
is
has
which
hazard
throughout the world
S t u d i e s were a l s o made on t h e preparatxon and p r o p e r t i e s
of
Cordierite-Zlrconia
composites
by
incorporating
Z srconia (both monoclinic and tetragonal p h a s e ) i n t o t h e
Cordxerite matrix
The
first part deals with synthesis of C o r d i e r ~ t e from
various
In each route the
routes
basic
compositxons
are s o formulated that the final fired product
is
obtained
Cordierite
T h e raw rnaterial used f o r different methods are
1)
Direct oxide route
11)
M ~ n e r a l raute
Pure MgO, Al2O3, S102
T w o types o f c l a y s were used,
a) Baqeshpur clay, alumina and
Talc
b ) Kundara Clay, alumina and Talc
111)
Flyash route
Samples
were
fabrication
Flyash, Alumina and Talc
prepared by
conventional
and sintered in
techniques
1360°C-1440°C
using
t o obtain dense products.
the
ceramic
range
A11 the
of
methods
yielded only Cordierite phase, With bulk density in
the
range of 2 40 to 2 54 gm/cc depending upon the method a f
preparation
Mechanical properties s u c h a s Modulus
Elastxcity (MOE) and Modulus of Rupture
(MOR)
(Flexural
Strength)
were measured f o r each composition
expansion
measurements were carrled out on sample
each
to 2 . 2 b x l ~ - ~ / * ~
1 95x10-'/'~
compare
well
with
All
these
detailed s t u d i e s were conducted on
prepared
from flyash
is
range
from
of
properties
t h e reported values.
Further,
though mullite
Thermal
&nd was Jound t o b e in the
composition
of
Cordzerite
T h e significant feature is
present
in
basic raw material
that
flyash,
it
completely
is
product
only
of
disappeared in
the
final
sintered
which s h o w s the presence o f Cordierite
crystalline phase indicating complete
Mullite
needle
like
matrlx
SEM picture s h o w s
The
structures
dispersed
the
dissolution
the
in
as
presence
a
of
homo~enious
EDOX analysis indicate that these n e e d l e s
are
o f Cordierite phase rich in M g
The
final part explains preparation and
Cordierite-Zirconia
prepared
from
Mineral
(11)
composites
by
routes
namely
two
Kundara
clay
lo%,
t-Zr02 were added in
using
were
and 1 4 4 0 q C
showed
higher
bulk
porosity
than
of
Under
the
route
The
true
samples
were
sintered
densities
sintered
composites
Apparent
w e r e maintained at less
(ZrSiOq) phase with increasing
the p r o c e s s p a r a m e t e r s and
and
seperately
X-ray a n a l y s i s showed increasing
1%
Zircon
all
and
Oxide
Cordierite-Zirconia
formulated and s a m p l e s
1380°C
cordierite
(1)
20% & 30% by wt
between
of
route t o which m-Zr02
In all, total of 12 c o m p o s i t i o n s o f
composites
properties
Zro2
sintering
amount
of
additions
conditions
employed, n o substantial amount o f Z i r c o n i a was retained
in
the composite
T h e mechanical p r o p e r t i e s
and MQR showed c o n s i d e r a b l e increase
of
composite
s l i g h t l y increased with
additions
iii
like
MOE
Thermal expansion
increasing
Zr02
T h e t h e s i s c o n c l u d e s with t h e s u m m a t i o n o f the physical,
thermal
and
mechanical p r o p e r t i e s
of
Cordierite
and
Cordierite-Zirconla c o m p o s i t e s
T h e work presented in t h l s t h e s i s w a s carried o u t b y the
author f o r t h e award o f M Sc
(Engg 1 d e g r e e from Indian
Institute o f Science, B a n g a l o r e
T h e author h o p e s
that
t h e s t u d i e s reported in t h i s t h e s i s f a r m s original piece
of work and h o p e s it t o b e o f w o r t h w h i l e c o n t r i b u t i o n t o
Ceramic and Material a s p e c t s o f t h e s u b ~ e c t