Abstract: A nitrogen oxide absorbing material, comprising a hollandite-type complex oxide having main metal elements comprising minimally of aluminum and tin, or zinc and tin, and a method of using that nitrogen oxide absorbing material comprising the steps of contacting the nitrogen oxide absorbing material with a gas containing nitrogen oxides. The method of reducing the adsorbed nitrogen oxides on the nitrogen oxide absorbing material includes the steps of releasing the nitrogen oxides from the nitrogen oxide absorbing material, and of reducing the released nitrogen oxides with a three way catalyst or other nitrogen oxide reducing catalysts.

Abstract: Silicon oxynitride sintered body is obtained by sintering a base starting material mixture comprising silicon oxynitride componentand a solution of at least one alkoxide selected from alkoxides of at least one element selected from the group consisting of Al, Sc, Y and rare-earth elements.Fiber-reinforced ceramic sintered body is obtained by sintering the base starting material mixture further inclusing 5-40% by weight of SiC whiskers and/or .beta.-Si.sub.3 N.sub.4 whiskers, wherein alkoxide component is 0.5-30% by weight as oxides.The alkoxide component is deposited on the other material powders and calcined to provide well dispersed oxide layer on the powder surface which forms uniform matrix phase giving high density by sintering. Sintered bodies (with or without whiskers) have low deterioration at high temperatures.

Abstract: Whisker-reinforced ceramics with high fracture toughness and strength consists essentially of 5-40 weight % SiC including SiC whiskers, 1-30 weight % of at least one kind of oxides of elements selected from the group consisting of Al, Sc, Y and rare-earth elements, and the balance being silicon oxynitride constituents, wherein said SiC whiskers are present in an amount of no less than 5 weight % of the total essential constituents.The silicon oxynitride constituents are Si.sub.2 N.sub.2 O or a mixture of silicon nitride and silica (0.83-1.22 by molar ratio), or a mixture of Si.sub.2 N.sub.2 O and said mixture of silicon nitride and silica. Silicon oxynitride and SiC phases are predominant.