Microhardness of Ceramics Obtained by Different Methods from Nanopowders of Different Oxides

The method of spark plasma sintering (SPS) is used for the creation of fine-grained ceramics on the basis of various nanodimensional powders of alumina and other oxides. A comparison of the microhardness of ceramic samples obtained from 11 alumina nanopowders and 2 of their composites was held. The microhardness of ceramics obtained both by SPS, and by the traditional method (at successive pressing and sintering) is compared. The dependence of ceramics microhardness on the phase composition of the initial nanopowder and the average size of its particles were investigated. Besides alumina (Al2O3) nanopowders, a comparison was made of the microhardness of ceramics from nanopowders of 13 other oxides (SiO2, ZnO, Fe3O4, CuO, Cr2O3, Gd2O3, CoO, WO3, MgO, Nb2O5, TiO2, Y2O3, ZrO2) obtained both by SPS, and by the traditional method. It is found that the microhardness of the ceramics created by the method of spark plasma sintering, is significantly higher than the microhardness of the ceramics obtained by the traditional method; at the SPS method the average size of ceramics grains decreases (to 1 micron and less).