PREPARATION AND ALKALI RESISTANCE OF ALUMINUM PIGMENTS ENCAPSULATED BY NANO-SILICON DIOXIDE MODIFIED BY SILANE COUPLING AGENT

Aluminum pigments encapsulated by nano-silicon dioxide modified by silane coupling agent were prepared with sol/gel method in the ethanol/water media and characterized with SEM and FTIR.Their stability in alkaline aqueous media was also examined.In addition,the mechanism of the course was analyzed.The silicon dioxide modified by silane coupling agent can form a covering layer on the surface of the aluminum pigments.The higher the content of the silane coupling agent,the less the granules in the covering layer and the higher the content of the organic film.The volume of the hydrogen evolved by the aluminum pigments encapsulated by nano-silicon dioxide modified by silane coupling agent was 2.7 percent of that evolved by unencapsulated ones in the alkaline aqueous media of pH=11 after 720 h.The silane coupling agent and silicon dioxide were not mixed simply but were polymerized,resulting in the formation of a homogeneous material.