Title :
Calorimetric characterization of magnetic pigment surfaces
Author :
Auweter, H. ; Jakusch, H.
Author_Institution :
BASF AG, Ludwigshafen, West Germany
fDate :
1/1/1990 12:00:00 AM
Abstract :
One of the most direct and sensitive ways of studying pigment surface properties is to measure the enthalpy changes which accompany the immersion of pigments in liquids. Different wetting liquids were used to test for H donor and H acceptor properties as well as to probe the polarity of the pigments´ surfaces. The measurements were performed in an isoperibol batch calorimeter. Results are presented for γ-Fe 2O3, CrO2, Co-modified γ-Fe2 O3, and barium ferrite pigments. It is found that Co-modified γ-Fe2O3 pigments are very polar, whereas CrO2 pigments have low polarities: H donor and H acceptor properties are less pronounced. It is found that barium ferrite pigments act very much like γ-Fe2O3 pigments. It is shown that the effects of surface treatment can clearly be monitored by calorimetry
Keywords :
calorimetry; chromium compounds; disperse systems; enthalpy; iron compounds; magnetic fluids; magnetic properties of fine particles; magnetic surface phenomena; surface chemistry; surface treatment; wetting; BaFe12O19 pigments; CrO2 pigments; CrO2:H; Fe2O3:Co,H; Fe2O3:H; H acceptor properties; H donor properties; calorimetric characterisation; effects of surface treatment; enthalpy changes; gamma Fe2O3 pigments; gamma Fe2O3:Co pigments; immersion; magnetic pigment surfaces; polarity; surface properties; wetting liquids; Barium; Calorimetry; Chemicals; Ethanol; Ferrites; Pigmentation; Production; Solvents; Surface treatment; Testing;
Journal_Title :
Magnetics, IEEE Transactions on