Abstract
The solid–solid interactions between nanosized pure and NiO-substituted ferric and titanium(IV) oxides have been investigated using XRD technique and microstructure studies, also magnetic properties were studied using vibrating samples magnetometer (VSM). The amounts of substituting Ni
2+ were
x
=
0, 0.2, 0.4, 0.6, 0.8 and 1
mole. A mixture equimolar proportions of finely powdered Fe
2O
3 and TiO
2 were mixed with NiO, ball milled, compressed at 250
kg/cm
2 and fired at 1200
°C for 4
h.
The obtained results showed that with substituting Ni
2+ concentration
x
=
0 only Fe
2TiO
5 phase is present (∼80
nm) which showed a very small saturation magnetic flux density (
B
s), remnant magnetic flux density (
B
r) and the maximum energy product (
BH)
max. By the addition of
x
=
0.2 NiO, new phases were observed NiTiO
3 and NiFe
2O
4 of crystallite sizes 160 and 110
nm, respectively. By the increase of substituting Ni
2+ concentration the NiTiO
3 and NiFe
2O
4 phases increased on the expense of Fe
2TiO
5 up to
x
=
0.4, then the increase in substituting Ni
2+ concentration led to a decrease in Fe
2TiO
5 and NiTiO
3 while NiFe
2O
4 increases which results in a great improvement of magnetic properties.
All samples exhibit a catalytic activity towards H
2O
2 decomposition and the values of rate constant increase with increasing amount of Ni
2+ substituting. The most acidic active sites are shown by specimens substituted with
x
=
0 this concludes that H
2O
2 decomposition is not favored on acidic active sites.