EFFECT OF SOME DISPERSING AUXILIARIES ON NANOSILICA DISPERSION INTO PASSIVE CHROME TRIVALENT SOLUTION

Abstract

In this paper, the dispersion of nanosilica in conversion solution trivalent chromium using variety of dispersion aids namely: SDS, PVP, AE-7, OP-10 and epomin. The results showed that the nanosilica could disperse in conversion solution in low pH (pH = 1.5). The solution containing nanosilica was uniform, having no agglomeration with SDS, PVP and AE-7 after 7-day preparation. The results of zeta potential and size distribution illustrated that AE-7 was the most effective for nanosilica dispersion in passive solution trivalent chromium with medium size of nanosilica in C2-nanosilica solution using AE-7 equal ~ 60 nm. However, there was a much diffirence size between the size of nanosilica in passive solution and initial nanosilica. As a result, nanosilica could disperse in passive solution at low pH with AE-7 but this was not effective enough to held dispersed solution in stable state.