sealing-in part is made of special ceramic and metal, which are widely used in various vacuum fields. ... 1. sealing-in part is made of special ceramic and metal.2. special ceramic can be 95% alumina, 99% alumina, zirconia, ... casting, dry casting or isopressing and so on. 3. metal material is mainly stainless steel, kovar, Invar, Molybdenum ... in various vacuum fileds. sealing-in piece (ceramic to metal)