Toshiyuki Nishio

Preparation of Fe2VAl Thermoelectric Module by RF Sputtering

An attempt to prepare Fe2VAl deposited film and the thermoelectric module using RF sputtering has been made. Sputtering target has been prepared using mechanical alloying of metallic powders and the subsequent pulse current sintering process. The obtained deposited film has had a lack of aluminum content compared to the composition of the starting material. Controlling of aluminum content for the preparation of Fe2VAl sputtering target has made it possible to obtain the desired material composition. The film has had the experimental thermoelectric force being similar to the one estimated from the measured thermoelectric data of the materials. Fe2VAl thermoelectric module of eight pairs with a film thickness of 4 μm has had an electric force of 31mV and 5.6μW.

PREPARATION OF Fe 2 VAl COMPOUND USING MA-PCS PROCESS AND THE THERMOELECTRIC PROPERTY

Fe-49.3at%V-26at%Al alloyed powder has been synthesized by mechanical alloying as the starting materials of pure iron, vanadium and Fe-38. lat%Al pre-alloyed powder. The use of pre-alloyed powder has led to a high collective of milled powder and precise compositional control. Milled powder has been successfully consolidated to a dense bulk compact using pulse current sintering process. The compact made of 360ks milled powder has had a power factor of 1.8 × 10 −3 (W·m −1 ·K −2 ). Grain refinement has had a tendency of a slight decrease of thermal conductivity.

DISCHARGE PHENOMENA AND EFFECT OF PULSE CONDITION IN PULSED CURRENT SINTERING

Discharge phenomena occurred by using aluminum powder and a BN die set instead of a normal graphite die set. Using the BN die set, high voltage was applied to the powder compact and the discharge condition was satisfied. The effect of pulse current on an interface temperature was investigated by thermal-image-analyzing with Al balls of 10mm in diameter. The temperature of the interface between two balls was larger than that of the body. The difference between the interface and the body temperature decreased with increasing the pulse frequency. The temperature difference in pulse current was higher than that in DC.