In situ surface modification of silicon carbide particles using Al3+ complexes and polyelectrolytes in aqueous suspensions

Silicon carbide (SiC) particles were modified in situ, using Al3+ complexes in aqueous media, via control of Al(NO3)3 concentration and pH. The Al3+ formed hydrolyzed complexes that adsorbed onto the charged sites on the SiC particle surfaces. As a result, the surface-modified SiC particles behaved in an alumina-like manner in the approximate pH range 5–8. The modified SiC particles were further treated with two types of polyelectrolytes that were sequentially adsorbed onto the particle surface, to give a maximum surface charge. As a result of this surface-modification process, the SiC could be dispersed with Al2O3 in aqueous media without heteroaggregation.