| 摘要 |
PROBLEM TO BE SOLVED: To more easily increase the relative density of a lanthanum boride sintered compact.SOLUTION: A lanthanum boride sintered compact 10 comprises incorporation phases 16 each containing lanthanum and silicon in a grain boundary part 14 between the adjacent crystalline particles 12 of lanthanum boride. An incorporation phase 16a existing at a triple point of the grain boundary part 14, another incorporation phase 16b existing along the grain boundary part 14 or the like is formed in the lanthanum boride sintered compact 10. Each of these incorporation phases 16 is based on lanthanum silicide (the compositional formula thereof is LaSi(0<x≤2)). A method for producing the lanthanum boride sintered compact 10 comprises: a step of compacting lanthanum boride in the coexistence of a silicon-containing material or compacting the silicon-containing material-incorporated lanthanum boride; and a sintering step of press-free sintering an obtained compact in an inert atmosphere. The lanthanum boride sintered compact 10 having such a structure exhibits the relative density equal to or higher than 92%, more preferably that equal to or higher than 94%. |
