Curie temp. and ferromagnetic permeability measuring appts. - uses coil surrounding sample heated by lamps and reflectors, and determines temp. at which abrupt change in inductance occurs

摘要

The appts. measures the Curie temperature of a ferromagnetic material or the variation of a magnetic permeability of a material as a function of e.g. the temperature. The sample is placed in a tube inside a coil imbedded in a refractory cement casing. It is heated by halogen lamps using elliptic reflectors. The temperature is controlled by a thermocouple fixed in the casing and measured by a thermocouple placed in a long narrow cavity in the tube. When the sample reaches the Curie temp. or when its magnetic permeability changes, the coil self-induction changes abruptly. This change is detected by measuring the impedance or by using an oscillator.