PURPOSE: To obtain boron nitride having high purity and density by the hot isotropic hydrostatic pressure treatment of powdery raw material of boron nitride and to prevent the corrosion, degradation, etc., of an MHD electric generator by using the boron nitride as an insulation material.
CONSTITUTION: Powdery raw material for boron nitride having high purity is filled in a vessel made of e.g. niobium or tantalum and the vessel is closed with a lid and sealed by welding under evacuation. The vacuum-sealed vessel is put into a hot isotropic hydrostatic pressure treatment apparatus and sintered. The vessel is opened to obtain a boron nitride having high purity, density and strength. An insulation part made of the boron nitride is used as insulation parts 4, 5 of the electrodes 2, 3 of an MHD electric generator and applied to the side contacting with the flow of a mixed work gas.
IKEDA SABURO
ISHIWATARI YUTAKA
TAKAHASHI MASASHI
