2017 Volume 125 Issue 6 Pages 509-512
Commercial Si3N4 powders coated with 0–30% amorphous Si3N4 nano-powders were fabricated successfully. Amorphous Si3N4 nano-powders coating were prepared through the reduction of silicon tetrachloride (SiCl4) by sodium in liquid ammonia at −45°C. Dense Si3N4 ceramics with 97.2% relative density of theoretic value were obtained from Si3N4 micro-powders coated with 30% nano-powders sintered by spark plasma sintering at 1500°C without sintering additives.