Effects of amino groups on dispersibility of silicon nitride powder in aqueous media

Silicon nitride (Si3N4) powders were subjected to amination modification by grafting gamma-aminopropyltriethoxysilane (APTES) via a direct blending method in solution. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the hydroxyl groups present on the surface of Si3N4 powder particles interacted with the silanols groups of APTES to combine through covalent bonding. Thermogravimetric analysis (TGA) suggested that the grafting of APTES on Si3N4 powder surface was successful with grafting content reaching up to 7%. Compared to native Si3N4, the surface hydrophilicity of amino Si3N4 powder was enhanced and dispersibility was improved. Overall, these findings indicated the promising aspects of amination modification and future potential use in environmental protection by using water instead of organic solvents during Si3N4 ceramic formation process.