The Effect of Rotation Speed during the Milling of Raw Powder on the Mechanical Strength of Si3N4 Ceramics

Si3N4 raw powder (ESP) with sintering additives was milled using Si3N4 mill and balls. The milling was carried out at rotation speeds of 64, 83, 110 and 150rpm for 48, 72 and 96h under the same condition of the volume ratios of balls, powder and liquid to the mill.The specific surface area of the milled powders and the bulk density of the bodies sintered are in proportion to the accumulated rotation number. However, relationships between the viscosity of the slurry, the average diameter of the powders, the bending strength of the bodies sintered and the accumulated rotation number at 64-110rpm did not show the same trend as those at 150rpm.