Getter Material And Evaporable Getter Device Using The Same, And Electron Tube

Abstract

The present invention provides a getter material configured by a pressed powder mixture comprising Ba—Al alloy powder and Ni powder, wherein when the pressed powder mixture is heated in a vacuum atmosphere or an inert gas atmosphere, a temperature at which an exothermic reaction starts is ranging from 750° C. to 900° C. According to this getter material, since the temperature at which the pressed powder mixture starts the exothermic reaction is set within a range from 750° C. to 900° C., there can be provided a getter material and an evaporation type getter device capable of suitably controlling an evaporation amount of getter components under a stable condition, and is excellent in responsiveness because a time ranging from a starting time of heating the getter material to a starting time of evaporation of the getter components can be shortened. In addition, the metal container to be filled with the getter material is free from deformation and melting, and a heat-evaporation process time of the getter material can be shortened, so that there can be provided the evaporation type getter device excellent in responsiveness because a time required for the electron tube to attain to a predetermined vacuum degree can be also shortened.

1 . A getter material configured by a pressed powder mixture comprising Ba—Al alloy powder and Ni powder, wherein when the pressed powder mixture is heated in a vacuum atmosphere or an inert gas atmosphere, a temperature at which an exothermic reaction starts is ranging from 750° C. to 900° C.  
   
   
       2 . The getter material according to  claim 1 , wherein the Ni powder has an average grain size of 10 μm or less.  
   
   
       3 . The getter material according to  claim 1  or  2 , wherein a ratio of Ni powder having an average grain size of 20 μm or more with respect to an entire Ni powder is 10 mass % or less.  
   
   
       4 . The getter material according to any one of  claims 1  to  3 , wherein the pressed powder mixture is a press-compacted body formed by press-compacting a power mixture comprising the Ba—Al alloy powder and the Ni powder at a compacting pressure of 400 MPa or more.  
   
   
       5 . The getter material according to  claim 4 , wherein the press-compacted body has an electrical resistivity of 20 mΩ-cm or less.  
   
   
       6 . An evaporation type getter device comprising: 
 a metal container; and    a getter material according to any one of  claims 1  to  5 , the getter material being filled in the metal container.    
   
   
       7 . The evaporation type getter device according to  claim 6 , wherein the metal container filled with a getter material is formed of at least one material selected from of Fe, Ni, Fe alloy and Ni alloy, and when assuming that a plate thickness of the metal container is t cm while a frequency of alternate current magnetic field for heating and evaporating Ba component from the getter material is f Hz, the plate thickness t of the metal container and the frequency f of alternate current induction field satisfy a relation formula: t≦12.7/(f) 1/2 .  
   
   
       8 . An evaporation type getter device comprising: 
 a metal container formed of at least one material selected from of Fe, Ni, Fe alloy and Ni alloy; and    a getter material configured by a pressed powder mixture comprising Ba—Al alloy powder and Ni powder that are filled in the metal container,    wherein when assuming that a plate thickness of the metal container is t cm while a frequency of alternate current magnetic field for heating and evaporating Ba component from the getter material is f Hz, the plate thickness t of the metal container and the frequency f of alternate current induction field satisfy a relation formula: t≦12.7/(f) 1/2 .    
   
   
       9 . An electron tube equipped with the evaporation type getter device according to any one of claims  6 ,  7  and  8 .