Measurement of curie temperature by an induction method

Abstract

An induction method to measure the curie temperature of ferro-magnetic materials is described. In this method the specimen whose curie temperature is to be measured is made the core of a circuit, the primary of which also acts as a furnace. The current induced in the secondary through the specimen is recorded by a millivoltmeter. Raising the temperature of the specimen by passing current through the primary results in loss of ferromagnetism of the sample and at the curie temperature due to complete and rapid loss of ferromagnetism a sudden reduction is seen from deflection in millivoltmeter is taken to be the curie temperature. The method has been standardised with armco iron and super spec pure nickel and the accuracy of determination is ± 3°C. (Messrs A.N. Sinha, Senior Technical Assistant and L.J. Balasundaram, Scientist, National Metallurgical Laboratory)