Alloy, sintered article, thermoelectric module and method for the production of a sintered article

Abstract

An alloy is provided that consists essentially ofwherein 0.06≤×≤ 0.24, 0.01 ≤y ≤0.06, 0/08≤z≤0.4, 0.9 ≤(a, b) ≤ 1.1, 0≤c≤ 0.05, 0≤d ≤ 0.05 and 0 ≤ e ≤ 0.1 and A is one or more of the elements in the group consisting of Zr, Hf, Sc, Y, La, and up to 5 atom % impurities.

1 . A method for the production of a sintered article, comprising:
 providing a starting material consisting essentially of
                     
 wherein 
         0.06   ≤   x   ≤   0   .24,         
         0.01   ≤   y   ≤   0   .06,         
         0.05   ≤   z   ≤   0   .4,         
         0.9   ≤       a   ,   b       ≤   1.1   ,         
         0   ≤   c   ≤   0.05   ,         
         0   ≤   d   ≤   0.05   ,         
         0   ≤   e   ≤   0   .1,         
 Wherein A is one or more of the elements in the group consisting of Zr, Hf, Sc, Y, La and up to 5 atom % impurities, 
   melting the starting material and subsequent solidification to form at least one block,   crushing the block,   grinding the crushed block, thereby forming a powder,   cold pressing the powder, thereby forming a green body,   sintering the green body, thereby producing a sintered article for a thermoelectric element.   
     
     
         2 . A method according to  claim 1 , wherein the green body is sintered at a maximum pressure of 1 MPa and at a temperature of 900° C. to 1200° C. for 0.5 h 24 h. 
     
     
         3 . A method according to  claim 1 , wherein 0.01 ≤ y ≤ 0.045 and/or 0.075 ≤ z ≤ 0.3. 
     
     
         4 . A method according to  claim 1 , wherein c = 0, d = 0 and e = 0. 
     
     
         5 . A method according to  claim 1 , wherein the sintered article has a grain size of greater than 1.25 µm. 
     
     
         6 . A method according to  claim 1 , wherein the sintered article has a density D, D being ≥ 90% of the theoretical density D i . 
     
     
         7 . A method according to  claim 1 , further comprising casting the molten starting material to form a block. 
     
     
         8 . A method according to  claim 1 , further comprising homogenising the block at a temperature of 700° C. to 1200° C. for 0.5 h to 100 h. 
     
     
         9 . A method according to  claim 1 , wherein the block is crushed by means of a jaw crusher. 
     
     
         10 . A method according to  claim 1 , wherein the crushing is carried out by means of a disc mill or a roller mill. 
     
     
         11 . A method according to  claim 1 , wherein the block is crushed to a coarse powder, the coarse powder is ground to a fine powder in a further grinding process and the fine powder is cold pressed. 
     
     
         12 . A method according to  claim 11 , the further grinding process being carried out by means of a planetary ball mill or a jet mill. 
     
     
         13 . A method according to  claim 1 , wherein the starting material is melted by means of vacuum induction melting. 
     
     
         14 . A method according to  claim 1 , wherein the block is homogenised in argon or in a vacuum. 
     
     
         15 . A method according to  claim 1 , wherein the green body is sintered in a protective gas or a vacuum. 
     
     
         16 . A method according to  claim 1 , further comprising homogenising the sintered article at a temperature of 600° C. to 1000° C. for 0.5 h to 100 h. 
     
     
         17 . A method according to  claim 1 , wherein the sintered article is further processed by means of sawing and/or grinding processes to form a plurality of working components.