Patent ID: 7670982

Claim:
A method for manufacturing a rare-earth oxide sintered body comprising the steps of: adding a boron compound at a ratio of 0.06 mol % or more and less than 25 mol % when converted into boron oxide (B 2 O 3 ) to oxide powder of at least one of La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Sc; forming the mixed powder; and performing sintering such that a resulting sintered body comprises at least one of La 2 O 3 , Nd 2 O 3 , Sm 2 O 3 , Eu 2 O 3 , Gd 2 O 3 , Dy 2 O 3 , Ho 2 O 3 , Er 2 O 3 , Tm 2 O 3 , Yb 2 O 3 , Lu 2 O 3 , and Sc 2 O 3 , and at least one of Ln 3 BO 6 (Ln=La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Lu), and Sc 3 BO 6 as a main constituent crystal thereof.