A chemical process for fabrication of Si3N4/BN nanocomposite was devised to improve the mechanical properties. Si3N4/BN nanocomposites containing 0 to 30 vol% hexagonal BN (h-BN) were successfully fabricated by hot-pressing α-Si3N4 powders, on which turbostratic BN (t-BN) with a disordered layer structure was partly coated. The t-BN coating on α-Si3N4 particles was prepared by reducing and heating α-Si3N4 particles covered with a mixture of boric acid and urea. TEM observations of this nanocomposite revealed that the nanosized hexagonal BN (h-BN) particles were homogeneously dispersed within Si3N4 grains as well as at grain boundaries. As expected from the rules of composites, Young's modulus of both micro- and nanocomposites decreased with an increase in h-BN content, while the fracture strength of the nanocomposites prepared in this work was significantly improved, compared with the conventional microcomposites.
|Number of pages||11|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - 2002 Nov 1|
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Chemistry