Prior to sintering, two kinds of powders were produced by milling Co3O4 and Zr as raw powder with each other's milling method such as horizontal ball milling and high energy ball milling. The first one was mixed as Co3O4 and Zr powders during horizontal ball milling and the other milled powder was synthesized as Co and ZrO2 powders during high energy ball milling. Each of the milled powders was consolidated by the High Frequency Induction Heated Sintering method within 3 minutes under the 1 GPa pressure, respectively. The relative densities of these specimens sintered from HFIHS were measured by the Archimedes method. The crystallite sizes of Co and ZrO2 in each composite were calculated by Suryanarayana and Grant Norton's formula. The mechanical properties of Co-ZrO2 composites consolidated by HFIHS from the horizontal ball milling method and high energy ball milling method were investigated from each surface indentation.

Keywords: Co-ZrO2; Composite; Sintering; Mechanical properties; Nanocrystalline