Synthesis and Characterization of Temperature Sensitivemagnetic Fluids

Abstract

The unusual magnetic properties exhibited by nanoparticles and their promising technological applications have attracted much interest in recent years. The magnetic fluid is considered to have applications in the field of heat transfer in solar systems and cooling of mechanical and electric heat sources. The Mn-Zn ferrite nanoparticles are used in the preparation of temperature sensitive magnetic fluid. The main aim of the present thesis is to prepare stable, sensitive magnetic fluid using Mn-Zn ferrite nanoparticles. This report begins with a detailed description of magnetism, ferrites, ferrofluids and their important applications in chapter 1.Chapter 2 deals with relevant literature review to understand the state of art in the field. The detail methodology of synthesis of nanoparticles and magnetic fluids along with various characterization techniques are incorporated in chapter 3.In chapter 4, we have analysed the results obtained from various tests of nanoparticles. Formation of single-phase Mn(1-x)ZnxFe2O4 nanoparticles at low temperature was confirmed by XRD. It was confirmed from TGA analysis that monolayer coating of oleic acid was successfully achieved, which prevents agglomeration of nanoparticles. This fact is confirmed by TEM study. Magnetization measurement reveals that as the Zn content in the sample increases, the saturation magnetization of the sample decreases. Further, the samples prepared at higher pH are strongly magnetic than their counter parts prepared at lower pH. This can be understandable from the fact that the increasing pH results into better crystallinity and larger size. The current study can be extended to prepare transformer oil based magnetic fluids, which has tremendous application potentials.