ISSN:
1435-1536
Keywords:
Magnetic fluids
;
Thermal conductivity
;
Colloidal Fe3O4 particles
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The thermal conductivity of a number of ferrofluids consisting of colloidally dispersed Fe3O4 particles in diester, hydrocarbon, water and fluorcarbon carriers have been measured at 38°C. The variation in thermal conductivity with particle concentration is well described by Tareef's equation (1940). This has enabled the ratio of the physical to magnetic size to be determined and compared with estimates of the ratio obtained from electron micrographs and magnetic measurements. The fit between theory and experiment is particularly good for hydrocarbon carrier fluids giving the ratio of solid to magnetic radiusR i/R m=1.24±0.03 compared with the value obtained from magnetic data and electron micrographs of 1.19±0.07. The corresponding value from the fluids with a diester carrier ranges between 1.1〈R d/R m〈1.3 which is again consistent with microscopy and magnetic data. The application of a magnetic field of 0.1 T had no noticeable effect on the thermal conductivities of ferrofluids.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01447973
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