Processing of non-oxidic powders in water. Part 1

Abstract

To suppress the reactivity of nanoscaled non-oxidic powders such as titanium nitride and silicon carbonitride against hydrolysis and oxidn., chem. surface modification with nitrogen contg. surfactants was investigated. Among these surfactants long chain primary amines, ethylene diamines and isocyanates were examd. Thermogravimetry, elemental anal. and the behavior against water vapor adsorption of the modified particles were used as methods to est. the protective capacity of the org. coating material. Best results were obtained by using a long chain ethylene diamine, which was indicated by a significant redn. of the powder oxidn. and an increase in particle hydrophobicity. Prepn. of a stable aq. dispersion without significant changes in the elemental compn. of the powder was achieved by application of water sol. surfactants to the surface modified particles. Very good results were obtained by application of an emulsion technique.