... refreactory.We can machinging ceramic rods, ceramic plunger, ceramic ring, ceramic insulated gasket, ceramic nozzle, ceramic pole, etc.Advantage:1. wear-resistanting ... , Si3N4 material .Specification Zirconia ceramic are applicated as shaft bearing ,plunger,sealing matetial and knife, with high density, hardess ,bending strength ... , we will try our best to meet you requirements. ceramic plunger