The Preparation Of Fe-Ni-Si-C By Mechanical Alloying And The Studies Of Its Magnetic Properties

Mechanical alloying(MA),which is a new technology of solid state reaction, has attracted much attention of materials researchers recently, because it can synthesize metastable materials such as amorphous phase, nanocrystallines, super-saturated solid solution, etc.Fe based nanocrystalline and amorphous materials had been produced by mechanical alloying in this thesis. The microstructure of the composites had been studied. And the magnetic properties of the composites had also been studied and analyzed.Fe-Ni-Si-C nanocrystalline and amorphous powders were produced by RS in tradition way. In such way, we can only get silky or bandy products. It is very important that we can get amorphous powder of Fe-Ni-Si-C alloy in large range. Fe-Ni-Si-C powders are both important soft magnetic materials. It is found that with the change of time, the grain size of the Fe-Ni-Si-C alloy keeps declining and the magnetic properties of them keep invariability. Under different atmosphere the changes are different. We can get some information about them.(1) Under some ball milling conditions, we can get Fe based nanocrystalline and amorphous materials.(2) The structure and the grain size of the alloys have been changed with the milling time and the atmosphere of the milling system. Oxygenation can prevent the atmosphere structure from producing.(3) The alloys produced by ball milling have obvious magnetic properties and which have changed with the milling time and milling atmosphere.(4)The coercive forces of the alloys have increased with the declining of the grain sizes.