Method for producing magnetostrictive element, sintering container and magnetostrictive element

Abstract

A setter 20 to be arranged in a sintering container 10 is provided with holes 21 to keep a compact 100 upright. The compact 100 is not in contact with the setter 20 at a temperature level at which the sintering reaction proceeds between them because of contraction of the compact 100 during sintering.

1 . A method for producing a magnetostrictive element comprising the steps of: 
 compacting a starting material powder into a shape in a magnetic field to prepare a compact; and    sintering said compact kept upright in a container.    
     
     
         2 . The method for producing a magnetostrictive element according to  claim 1 , wherein: 
 said compact is kept in said container upright by a supporting member,    said supporting member is not in contact with said compact when said compact contracts as a result of sintering during said sintering step.    
     
     
         3 . The method for producing a magnetostrictive element according to  claim 1 , wherein: 
 said compact contains Tb, Dy and Fe, and can be sintered into a magnetostrictive element.    
     
     
         4 . The method for producing a magnetostrictive element according to  claim 1 , wherein: 
 said compact is stick-shaped.    
     
     
         5 . A sintering container, which holds an object to be sintered into a magnetostrictive element during a sintering step, comprising: 
 a container body having a basal plane and an opening;    a freely detachable lid to cover said opening; and    a setter arranged in said container body and provided with a cavity, wherein:    said object can be set in said cavity in such a way that said object extends along the direction in which a magnetostrictive element is driven after said object is sintered into said magnetostrictive element.    
     
     
         6 . The sintering container according to  claim 5 , wherein: 
 said object to be sintered is longitudinally shaped, and    said object can be set in said cavity in such a way that its major axis extends almost vertically.    
     
     
         7 . The sintering container according to  claim 6 , wherein: 
 thickness of said setter is almost the same as longitudinal length of said object to be sintered.    
     
     
         8 . The sintering container according to  claim 5 , wherein: 
 said setter is made of a material which reacts with said object to be sintered at temperature higher than temperature at which said object contracts as a result of sintering.    
     
     
         9 . The sintering container according to  claim 5 , wherein: 
 said setter is made of a material containing Dy 2 O 3 .    
     
     
         10 . A magnetostrictive element comprising a sintered body having a composition represented by Formula (1) RT y  (wherein, R represents one or more rare earth elements (providing that the rare earth elements include Y), T represents one or more transition metal elements, and 1<y<4), wherein: 
 spacing of lattice planes in said magnetostrictive element as-sintered, is almost uniform.    
     
     
         11 . The magnetostrictive element according to  claim 10 , wherein: 
 said sintered body has a composition represented by Formula (2) Tb a Dy (1-a) T y  (wherein, 0.27<a≦0.50).    
     
     
         12 . The magnetostrictive element according to  claim 10 , wherein: 
 in the [222] orientation in the X-ray intensity distribution, a half width of said magnetostrictive element is between 0.05 and 0.70.    
     
     
         13 . A magnetostrictive element comprising a sintered body having a composition represented by Formula (2) Tb a Dy (1-a) T y  (wherein, 0.27<a≦0.50, T represents one or more transition metal elements, and 1<y<4), wherein: 
 a half width of said magnetostrictive element is between 0.05 and 0.70, in the [222] orientation in the X-ray intensity distribution.    
     
     
         14 . The magnetostrictive element according to  claim 13 , wherein: 
 said T is Fe.    
     
     
         15 . The magnetostrictive element according to  claim 13 , which has a magnetostrictive value of 1100 ppm or more in a magnetic field of 1 kOe.