Nanosilver-coated porous SiC-Si3N4 composite using microwave-assisted process

Using a novel microwave-assisted process, nano-Ag-coated continuous porous SiC-Si3N4 substrate was fabricated from a solution containing AgNO3 salts and ethylene glycol. The detailed microstructure of the fabricated substrate was investigated depending on the amount of AgNO3 salts in the starting solution and the microwave irradiation time. From a solution containing 0.4 g of AgNO3 for 60 s irradiation time, the Ag nanoparticles, similar to 25 nm in diameter, were homogeneously coated on the continuous porous SiC-Si3N4 matrix as well as on the surface of the Si3N4 whiskers. However, the Ag nanoparticles (similar to 15 nm) deposited from a solution containing 0.6 g of AgNO3 for 60 s irradiation time showed maximum homogeneity and narrow size distribution. The components of Si, N, and Ag were homogeneously distributed on the deposited layer. The deposited Ag nanoparticles covered with a thin (similar to 2 nm), amorphous layer had nanocrystallinity and adhered well to the surface of the Si3N4 whiskers.