The emission of secondary electrons and ions from clean Au, GHrAu and Si02 surfaces at impact of slow (v= 0.3 v-) ions has been measured as a finction of incident ion charge for l+3+. Yields of negative secondary ions from Si02 and CHY-AUwere recorded in parallel with electron emission data and exhibit a q", n=l, dependency on incident ion charge. A direct comparison of collisional and electronic contributions to secondary ion production from Si02 films using abeam of charge state equilibrated Xe-(at 2.75 keV/u) shows positive and negative secondary ion yield increases with incident ion charge of >400. Results are dkcussed in relation to key signatures of electronic sputtering by Coulomb explosions.