| abstract |
A ceramic contains, in mass percent: Si 3 N 4 : 20.0 to 60.0%, ZrO 2 : 25.0 to 70.0%, and one or more oxides selected from MgO, Y 2 O 3 , CeO 2 , CaO, HfO 2 , TiO 2 , Al 2 O 3 , SiO 2 , MoO 3 , CrO, CoO, ZnO, Ga 2 O 3 , Ta 2 O 5 , NiO, and V 2 O 5 : 5.0 to 15.0%. The ceramic has a coefficient of thermal expansion as high as that of silicon and an excellent mechanical strength, allows fine machining with high precision, and prevents particles from being produced. |