Development And Application Of Liquid Metal Magnetic Susceptibility Meter

Investigating the physical properties of the melted alloy is more generally used among those ways investigating the structure of the melted alloy indirectly. Many works has been done in studying the magnetic susceptibility variation in melt, in China, however, this kind of work haven't been developed properly.In the present work, the author introduces in detail the design, trial-manufacture and application of a magnetic susceptibility measuring device. Based on the fundamental principles of electromagnetic induction, the device is mainly composed of a couple of differential coils with ferroamorphous cores, and the magnetic susceptibility variation of the sample can be calculated through measuring the output voltage of the secondary coil. The magnetic susceptibility variation in a liquid or solid sample can be measured by this device, with the help of an inferred thermometer, we can measure transitions within the sample at different temperatures.With this device, the author measured the variation of the magnetic susceptibility of a series of alloys and metals when their structure changes at different temperatures. That includes the magnetic susceptibility variation of Cu-Sn alloys, Co_97.5Sn_20.5 alloys and Pb melt with temperature.Based on results of magnetic susceptibility variation of Cu-Sn alloys at different composition and their viscosity and XRD analysis, the author conclude that its liquid structure has diverse form at different temperature; furthermore, its susceptibility changes when there are structural transition, and the variation itself varies obviously along with the composition. Compared the result of the susceptibility and thermal measurement of the Co_97.5Sn_20.5 alloys, it is found that different means of experiment have different identification ability to the change of the structure. It is found that the structure of the molten lead changes in different temperature, based on the result of the susceptibility of the sample and the result of the experiment on its viscosity, density and its DSC, this is further confirmed by the liquid state XRD measurement.