Against the background of energy problems and power supply problems such as nuclear power generation, research on building a society using distributed power sources is currently underway.

　Thermoelectric power generation technology, which is a power generation method that uses heat, is also attracting attention as one of the distributed power sources.Since the power is generated by the physical phenomenon of a solid element, there are advantages such as quietness without a drive unit, compatibility with various scales, cleanliness, and constant power generation.

　In the laboratory of Dr. Maruyama, we have been researching boron-based thermoelectric materials that are lighter than the bismuth-tellurium-based compounds currently in practical use as thermoelectric conversion devices and have relatively good thermoelectric properties even at high temperatures.However, boron-based thermoelectric materials such as boron carbide have the characteristics of being "brittle" and "difficult to harden", and there is a problem that they must be baked at a high temperature of nearly 2000 degrees in order to produce a member of practical size. there were.

　Under these circumstances, we decided to use a new technology called the discharge plasma sintering method and mix the raw material powder with a metal with a weight ratio of 10 to 15% to lower the sintering temperature of the boron carbide member to about 1700 ° C. Successful.In addition, the new material synthesized by this method has an electrical conductivity increased by about 1.5 times due to the mixture of metals, showing excellent properties as a thermoelectric material.

　When a boron-based thermoelectric element is completed, it is expected to expand its application range to automobile engines and heat engines in factories by taking advantage of its characteristics of being lighter and harder than conventional thermoelectric materials.

reference:[Tokyo City University] Developed a new material that can convert the waste heat of a car into electricity