Protecting nanoscaled non-oxidic particles from oxygen uptake by coating with nitrogen-containing surfactants.
To suppress the reactivity of nanoscaled non-oxidic powders of titanium nitride (TiN) and silicon carbonitride (SiCN) against hydrolysis and oxidation, chemical surface modification with nitrogen-containing surfactants was investigated. Among these surfactants, long-chain primary amines, ethylenediamines, guanidines, nitriles, isocyanates, and succinimides were examined. Thermogravimetry, elemental analysis, and behavior against the water-vapor adsorption of the modified particles were used as methods to estimate the protective capacity of the organic 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 oxidation toward the higher temperatures and an increase of the particle hydrophobicity. A long-chain succinimide was found to be the most effective in dispersing nanoscaled TiN in organic media. Preparation of a stable aqueous dispersion without significant changes in the elemental composition of the powder was achieved by the application of an ionic surfactant to the surface-modified particles.
Müller
Rainer
R
Laboratory of Interface Chemistry, University of Regensburg, Universitätsstrasse 31, D-93053, Regensburg, Germany. rainer.mueller@chemie.uni-regensburg.de
Knapp
Martin
M
Heckmann
Klaus
K
von Ruthendorf
Monika
M
Boden
Gottfried
G
D006868:Hydrolysis; D049329:Nanostructures / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010316:Particle Size; D017655:Silicon Compounds / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D017655:Silicon Compounds; D013501:Surface-Active Agents; D014867:Water; C041500:titanium nitride; D014025:Titanium; D009584:Nitrogen; D010100:Oxygen