Protecting Nanoscaled Non-oxidic Particles from Oxygen Uptake by Coating with Nitrogen-Containing Surfactants

Abstract

To suppress the reactivity of nanoscaled nonoxidic powders of Ti nitride (TiN) and Si carbonitride (SiCN) against hydrolysis and oxidn., chem. surface modification with N-contg. surfactants was studied. Among these surfactants, long-chain primary amines, ethylenediamines, guanidines, nitriles, isocyanates, and succinimides were examd. TG, elemental anal., and behavior against the H2O-vapor adsorption of the modified particles were used as methods to est. the protective capacity of the org. coating material. The best results were obtained by using the long-chain amines and octadecylisocyanate, which were indicated by a significant shift of the powder oxidn. toward the higher temps. and an increase of the particle hydrophobicity. A long-chain succinimide is the most effective in dispersing nanoscaled TiN in org. media. Prepn. of a stable aq. dispersion without significant changes in the elemental compn. of the powder was achieved by the application of an ionic surfactant to the surface-modified particles.