Method for Storing Target Comprising Rare Earth Metal or Oxide Thereof

Abstract

Provided is a method for storing a target comprising a rare earth metal or oxide thereof, wherein oxide of the same rare earth metal as the material of the rare earth metal or its oxide target to be stored is introduced as a desiccant into a container or a film-type seal for storing the target, and the target is stored by sealing the storage container or the film-type seal. This invention aims to provide technology for enabling the long-term storage of a target by devising the method for storing a target comprising a rare earth metal or oxide thereof, and thereby inhibiting the pulverization of the target caused by the oxidation and hydroxylation of such target due to the ingress of air.

1 . A method for storing a target comprising a rare earth metal or oxide thereof, wherein oxide of the same rare earth metal as the material of the target comprising the rare earth metal or oxide thereof to be stored is introduced as a desiccant into a container or a film-type seal for storing the target, and the target is stored by sealing the container or the film-type seal. 
     
     
         2 . A method for storing a target comprising a rare earth metal or oxide thereof, wherein rare earth metal oxide having greater hygroscopic property than the material of the target comprising the rare earth metal or oxide thereof to be stored is introduced as a desiccant into a container or a film-type seal for storing the target, and the target is stored by sealing the container or the film-type seal. 
     
     
         3 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 2 , wherein the target comprises two or more types of rare earth metals or their oxides, and wherein an oxide of the rare earth metal with the greatest hygroscopic property is used as the desiccant. 
     
     
         4 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 3 , wherein the step of sealing is vacuum sealing. 
     
     
         5 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 3 , wherein the step of sealing is vacuum sealing with a flexible film. 
     
     
         6 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 3 , further comprising the step of filling inert gas having a dew point of −80° C. or less into the container or film-type seal and encapsulating the target. 
     
     
         7 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 6 , wherein the rare earth metal oxide to be used as the desiccant is mounted on or filled in a space created when the target is encapsulated. 
     
     
         8 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 2 , wherein the rare earth metal configuring the target is La or contains La. 
     
     
         9 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 8 , wherein the rare earth metal oxide to be used as the desiccant is La oxide. 
     
     
         10 . The method for storing a target comprising a rare earth metal or oxide thereof according to  claim 9 , wherein the amount of moisture penetration through the flexible film to be used in encapsulating and storing the target or the amount of moisture ingress into the container from the outside is 0.1 g/m 2 ·24 h or less. 
     
     
         11 . The method according to  claim 2 , further comprising the step of filling inert gas having a dew point of −80° C. or less into the container or film-type seal and encapsulating the target. 
     
     
         12 . The method according to  claim 2 , wherein the oxide to be used as the desiccant is mounted on or filled in a space created when the target is encapsulated by the container or film-type seal. 
     
     
         13 . The method according to  claim 2 , wherein an amount of moisture penetration through the flexible film to be used in encapsulating and storing the target or the amount of moisture ingress into the container from the outside is 0.1 g/m 2 ·24 h or less. 
     
     
         14 . The method according to  claim 1 , wherein the step of sealing is vacuum sealing. 
     
     
         15 . The method according to  claim 1 , wherein the step of sealing is vacuum sealing with a flexible film. 
     
     
         16 . The method according to  claim 1 , further comprising the step of filling inert gas having a dew point of −80° C. or less into the container or film-type seal and encapsulating the target. 
     
     
         17 . The method according to  claim 1 , wherein the oxide to be used as the desiccant is mounted on or filled in a space created when the target is encapsulated by the container or film-type seal. 
     
     
         18 . The method according to  claim 1 , wherein the rare earth metal configuring the target is La or contains La. 
     
     
         19 . The method according to  claim 19 , wherein the oxide to be used as the desiccant is La oxide. 
     
     
         20 . The method according to  claim 1 , wherein an amount of moisture penetration through the flexible film to be used in encapsulating and storing the target or the amount of moisture ingress into the container from the outside is 0.1 g/m 2 ·24 h or less.