The chromate conversion coatings treatment of aluminum was treated with 90 cm3 of boiling water for 5 min. The resultant solution was poured into solid phase extraction column (IBC Advanced Technologies Inc., Cr-02 type) and eluted with 2 cm3 of 3 mol/dm3 hydrochloric acid solution. The resultant solution was measured with Digital pack test for Cr (VI) (Kyoritsu Chemical-Check. Lab., Corp). The required time for total analytical procedure was faster than 10 min. The solid phase extraction column could be used repeatedly about 300 times or more. The minimum limit of determination of chromium (VI) was 0.004 mg/dm3.
Precursor solutions were prepared through hydrolysis of ethoxysilanes possessing acetoxy group such as 3-acetoxypropyltriethoxysilane, acetoxymethyltriethoxysilane, and tetraethoxysilane in ethyl acetate containing poly(methyl methacrylate) (PMMA). The PMMA-silica composite films prepared on glass substrates using the solutions described above exhibited high pencil hardness of 4-8 H compared to H for PMMA film. The composite films also have higher adhesiveness than PMMA film.
Nano-sized CeO2/carbon cluster composite materials were prepared through calcination of a cerium(III) acetate/starch complex. ESR spectral examinations suggest an electron transfer process of CeO2→carbon clusters with an oxidation site at CeO2 and a reduction site at carbon clusters. The materials were found to have oxidation-reduction capability under visible light irradiation.