| 摘要 |
PROBLEM TO BE SOLVED: To provide a hexagonal boron nitride(hBN) sintered compact having a low density and low gas permeability, which is used as a tool usable under a high temperature gaseous hydrogen atmosphere. SOLUTION: The hBN sintered compact having a low density and low gas permeability has a density of <=1.5 g/cm3 and an amount of permeable gas of <=15 cm3/min. A method of producing the hexagonal boron nitride sintered compact comprises forming hexagonal boron nitride powder having an average particle size (D50) of <=10 μm and being characterized in that the relation between the diameter when cumulative mass attains 10% (D10) and the diameter when cumulative mass attains 90% (D90) is expressed by formula: D90-D10<=25 μm and then subjecting the formed body to normal pressure sintering under a non-oxidizing atmosphere. |
