Synthesis and Characterization of Nanosized Fe₂O₃ Pigments

Table 3

Physical and chemical properties of α-Fe₂O₃ nanoparticles prepared using microemulsion method.

Physical and chemical properties	Fe2O3 pigment prepared using
	0.2 M Fe2(SO4)3	0.4 M Fe2(SO4)3	0.6 M Fe2(SO4)3
Average particles size	9	14	19
Sp. Gr.	5.16	5.1	4.99
Solubility	Insoluble	Insoluble	Insoluble
Oil abs.	27	26	24
Hiding power	4.5	4.3	4.1
Resistance against heating at (700^°C)	Excellent	Excellent	Excellent
Fastness properties against
Sulfuric acid 5%	Excellent	Excellent	Excellent
Hydrochloric acid 5%	V. Good	V. Good	V. Good
Sod. Hyroxide, 2%	Excellent	Excellent	Excellent
Sod, Carbonate, 5%	Excellent	Excellent	Excellent
Cal. Hydroxide (Saturated Solution)	V. Good	V. Good	V. Good
Organic Solvents^*	Insoluble	Insoluble	Insoluble
Linseed Oil	Insoluble	Insoluble	Insoluble
Oleic Acid	Insoluble	Insoluble	Insoluble

^*Water, ethanol, acetone, chloroform, carbon tetrachloride, toluene, xylene, and tetrahydrofuran.