Thermoelectric Element

Abstract

A thermoelectric element formed of a sintered body of a semiconductor comprising at least two kinds of elements selected from the group consisting of Bi, Te, Se and Sb, and having a micro-Vickers' hardness of not smaller than 0.5 GPa. The thermoelectric element has a hardness of not smaller than 0.5 GPa, and exhibits a large resistance against deformation, and is not easily broken by deformation. As a result, breakage due to deformation is prevented and a highly reliable thermoelectric element is realized even when a shape factor which is a ratio of the sectional area of the thermoelectric element to the height thereof, is increased and even when the element density is increased.

1 - 8 . (canceled)  
   
   
       9 . A method of producing a thermoelectric element comprising the steps of: 
 preparing a starting powder of a semiconductor containing at least two kinds of elements selected from the group consisting of Bi, Te, Se and Sb;    reducing said starting powder or a molded article of said starting powder with hydrogen;    starting the sintering by heating by feeding a pulse current to said starting powder or to said molded article after said reduction treatment with hydrogen;    starting the application of pressure of 25 MPa to 80 MPa near a temperature at which said starting powder or said molded article starts shrinking;    sintering said starting powder or said molded article at a temperature of not lower than 300° C. while applying the pressure; and    machining the obtained sintered body into a predetermined shape.    
   
   
       10 . A method of producing a thermoelectric element according to  claim 9 , wherein when the temperature at which the starting powder or the molded article starts shrinking is denoted by T, the application of the pressure starts at a temperature of from (T−30) to (T+50)° C.  
   
   
       11 . A method of producing a thermoelectric element according to  claim 9 , wherein, as measured by a laser diffraction method, said starting powder has a particle diameter (D50) of from 0.5 to 10 μm at a cumulative weight ratio of 50%, has a particle diameter (D90) of from 0.7 to 20 μm at a cumulative weight ratio of 90%, and a particle diameter ratio D90/D50 is from 1.2 to 4.0.  
   
   
       12 . A method of producing a thermoelectric element according to  claim 9 , wherein said starting powder is at least one of Bi 2 Te 3 , Sb 2 Te 3 , or Bi 2 Se 3 .  
   
   
       13 . A method of producing a thermoelectric element according to  claim 10 , wherein said starting powder contains a halogen compound.