| 摘要 |
PROBLEM TO BE SOLVED: To obtain a yttrium borate and a rare earth element polyborate useful as a high functional material by giving a structure formed by combining yttrium with boron in a specific ratio and a structure formed by replacing a part of yttrium of the structural body by a rare earth element. SOLUTION: The objective yttrium borate is expressed by a general formula, YB25+x (-5<x<5). The another objective rare earth element polyborate is expressed by a general formula, Yy M1-y B25+x (M represents at least one kind of an element selected from a group consisting of Gd, Tb, Dy and Ho, -5<x<5 and 0<=y<1). The yttrium borate is produced as follows: a mixture is prepared by mixing one of YB2 , YB4 , YB6 and YB12 (YB4 easily obtained as an article on the market is suitable) with B to have the composition of the formula, YB25+x ; the mixture is molded; and the molded body is allowed to react under vacuum at 1,650-1,850 deg.C. The rare earth element polyborate is produced by the same method. |
