Heat-insulating material

Abstract

A heat-insulating material is provided in which thermal conductivity is controlled not to increase and good insulation properties are held even in a high temperature range. The heat-insulating material is formed of a spinel porous sintered body having a porosity of 65 to 90 vol. % and represented by a chemical formula XAl2O4 (X═Zn, Fe, Mg, Ni, or Mn) which is arranged such that large pores having a diameter of greater than 1000 μm occupy 25 vol. % or less of the total pore volume, fine pores having a diameter of 0.45 μm or less occupy 5 to 40 vol. % of the volume of the pores having a diameter of 1000 μm or less, at least one pore-diameter distribution peak is within a range of 0.14 to 10 μm, and is formed of sintered particles having a calculated average particle diameter of 0.04 to 1 μm.

Dependencies are inferred from the claim text.