Civil Engineering Reference
In-Depth Information
[Fe
2+
] = 1.0 mol/l
30
20
20
4 hours in FeCl
2
10
[Fe
2+
] = 0.1 mol/l
10
0
0
2 hours in FeCl
2
[Fe
2+
] = 0.01 mol/l
-10
-10
-20
-20
-30
-1.0
-0.5
0.0
0.5
1.0
-1.0
-0.5
0.0
Field (Tesia)
0.5
1.0
(
a
)
(
b
)
Field (Tesia)
Figure 17.4
(a) Field-dependent magnetization shows increase in saturation magnetization M
S
with
increase in concentration of Fe
2+
ions in precursor solution, and (b) with soaking time of BC in aqueous
FeCl
2
.4H
2
O solution.
Figure 17.5
(a) Ferrite-BC composite synthesized without sonication and surfactant PEG shows
agglomerated magnetite particles; (b) sonication alone leads to relatively dispersed magnetite particles;
(c) with sonication and PEG the magnetite particles are well dispersed and also larger. Inset shows the
l exibility and magnetic actuation of the composite.
Figure 17.6
(a) Homogeneous dispersion of magnetite particles along the i bers surface of BC with
inset showing the higher water contact angle (WCA) and oil contact angle (OCA) for the FAS-treated
magnetite-BC composite. (b) Magnetic actuation of FAS-treated magnetite BC being demonstrated using
a simple bar magnet.
as 400 emu/cm
3
and a coercivity of 1700 Oe (Figure 17.7a). h e aerogel sheet exhibits
mechanical l exibility with 180° bendability without any damage. h e aerogel under
compression has a low modulus of 0.15 MPa, while the xerogel has a modulus of 3 GPa
in tension (Figure 17.7b). h ese results show that the strength of the composite can be
varied by varying the drying and compression method.
