Abstract
Silicon nitride nanopowder was fabricated from a silicon nitride sub-micrometer powder by high energy milling. The sub-micrometer Si3N4 powder, 2 mol% of Al2O3 and 5 mol% of Y2O3 are mixed and then high-energy milled with Si3N4 balls as milling media in a Si3N4–lined pot filled with N2. Silicon nitride nanopowder with about 20 nm in diameter was obtained by high-energy milling at 475 rpm for 4 hs. Phase identification by XRD and TEM observation showed that the high-energy milled powder consisted of nanopowder with glassy phase. Effect of metallic aluminum was invesigated as a grinding additive. The addition of metallic aluminum enhanced the high-energy milling. These results suggest that nanopowder can be prepared by grinding method.
