Rare earth alloy-melting crucible and rare earth alloy

Abstract

A crucible comprising Al 2 O 3 and at least one selected from rare earth oxides inclusive of Y 2 O 3 as main components and characterized by firing at 500-1,800° C., the distribution of the rare earth oxide at a higher proportion in a fine particle portion having a particle size of up to 0.5 mm than in a coarse particle portion having a particle size in excess of 0.5 mm, and the substantial absence of the reaction product of the rare earth oxide with Al 2 O 3 is suitable for the melting of a rare earth alloy.

1 . A crucible for the melting of a rare earth alloy, comprising Al 2 O 3  and at least one selected from rare earth oxides inclusive of Y 2 O 3  as main components, wherein 
 the crucible is obtained by mixing particles and firing at 500 to 1,800° C., and is substantially free of a reaction product of the rare earth oxide with Al 2 O 3 , the particles comprising a fine particle portion consisting of fine particles having a particle size of up to 0.5 mm and a coarse particle portion consisting of coarse particles having a particle size in excess of 0.5 mm, and the fine particle portion accounts for 10 to 60% by volume, and    the fine particle portion contains 2 to 100% by volume of the rare earth oxide, the coarse particle portion contains 20 to 100% by volume of Al 2 O 3  having a particle size of more than 2 mm, and the rare earth oxide is distributed at a higher proportion in the fine particle portion than in the coarse particle portion.    
   
   
       2 . A crucible for the melting of a rare earth alloy, comprising Al 2 TiO 5  and at least one selected from rare earth oxides inclusive of Y 2 O 3  as main components, wherein 
 the crucible is obtained by mixing particles and firing at 500 to 1,800° C., and is substantially free of a reaction product of the rare earth oxide with Al 2 TiO 5 , the particles comprising a fine particle portion consisting of fine particles having a particle size of up to 0.5 mm and a coarse particle portion consisting of coarse particles having a particle size in excess of 0.5 mm, and the fine particle portion accounts for 10 to 60% by volume, and    the fine particle portion contains 2 to 100% by volume of the rare earth oxide, the coarse particle portion contains at least 50% by volume of Al 2 TiO 5 , and the rare earth oxide is distributed at a higher proportion in the fine particle portion than in the coarse particle portion.    
   
   
       3 . The crucible of  claim 1 , wherein at least 60% by volume of the rare earth oxides in the entire crucible is present in the fine particle portion.  
   
   
       4 . The crucible of  claim 2 , wherein at least 60% by volume of the rare earth oxides in the entire crucible is present in the fine particle portion.  
   
   
       5 . A method of preparing a crucible for the melting of a rare earth alloy, comprising Al 2 O 3  and at least one selected from rare earth oxides inclusive of Y 2 O 3  as main components, comprising 
 mixing particles and firing at 500 to 1,800° C., the particles comprising a fine particle portion consisting of fine particles having a particle size of up to 0.5 mm and a coarse particle portion consisting of coarse particles having a particle size in excess of 0.5 mm, and the fine particle portion accounts for 10 to 60% by volume,    the fine particle portion contains 2 to 100% by volume of the rare earth oxide, the coarse particle portion contains 20 to 100% by volume of Al 2 O 3  having a particle size of more than 2 mm, and the rare earth oxide is distributed at a higher proportion in the fine particle portion than in the coarse particle portion, and    the crucible being substantially free of a reaction product of the rare earth oxide with Al 2 O 3 .    
   
   
       6 . A method of preparing a crucible for the melting of a rare earth alloy, comprising Al 2 TiO 5  and at least one selected from rare earth oxides inclusive of Y 2 O 3  as main components, comprising 
 mixing particles and firing at 500 to 1,800° C., the particles comprising a fine particle portion consisting of fine particles having a particle size of up to 0.5 mm and a coarse particle portion consisting of coarse particles having a particle size in excess of 0.5 mm, and the fine particle portion accounts for 10 to 60% by volume,    the fine particle portion contains 2 to 100% by volume of the rare earth oxide, the coarse particle portion contains at least 50% by volume of Al 2 TiO 5 , and the rare earth oxide is distributed at a higher proportion in the fine particle portion than in the coarse particle portion, and    the crucible being substantially free of a reaction product of the rare earth oxide with Al 2 TiO 5 .